In this paper we propose a module that uses features learned by a deep convolutional neural network to infer areas of corrosion and segment pixels to corrosion areas of inspection interest. Our segmentation module is based on eigen tree decomposition and information based decision criteria. To interrogate performance we use several state-of-the-art deep learning architectures and compare to our approach. The results indicate that our method produces better results in terms of accuracy and precision, whilst maintaining good (f-score) significance over the entire dataset.

This paper presents an acoustic emission (AE) detection method for refined oil storage tanks, enabling online detection of corrosion points and microleakage in the tank floor. The method utilizes an explosion-proof acoustic emission instrument to detect the floor of a refined oil storage tank. By calculating the time difference between the defective acoustic signal and the speed of acoustic wave transmission, a mathematical model is constructed to analyze the detected signals. A technical scheme for acoustic emission detection in storage tanks is designed, and the instru-ment is used to carry out acoustic emission testing on the product oil storage tank floor. Based on these test results, location analysis of acoustic emission sources is conducted on the bottom plate of the tank, evaluating its corrosion condition accurately. The consistency between the evaluation and subsequent open tank tests confirms that using acoustic emission technology effectively captures corrosion signals from product oil storage tank bottoms. Consequently, it significantly improves inspection efficiency by avoiding unnecessary tank-opening operations. Combining this method with open tank inspection operations such as the leakage magnetic method, one can fully grasp the status of the refined oil storage tanks.

Although various atmospheric corrosion simulation models have been developed that give good results, industrial environments are still challenging. This paper aims to investigate the effect industrial atmospheres in Bor on the mechanical properties of structural steel S235JR and to create a constitutive model and also laboratory experimental conditions that will give the best results as an accelerated corrosion test. Atmospheric corrosion tests lasted six months, using sites close to the Electrolytic Refining Plant and Sulphuric Acid Plant, as well as air quality monitoring stations at a remote location in the city of Bor. The laboratory experiments included a salt chamber test lasting 120 h and 240 h and immersing the specimen in the electrolyte from the Electrolytic Refining Plant for 30 days. The results were compared with the standard specimens stored in the laboratory. The X-ray diffraction (XRD) method was used to identify the composition of corrosion products. The scanning electron microscopy (SEM) analysis was applied to analyze the fracture surfaces of the specimens. The use of the Complete Gurson Model (CGM) described the tensile characteristics of the corroded specimens. The study has shown that an enhanced acceleration model and conditions could be developed using numerical analysis of the test results.

This study explores the stability of electrodeposited copper catalysts utilized in electrochemical CO2 reduction (ECR) across various amine media. The focus is on understanding the influence of different amine types, corrosion ramifications, and the efficacy of pulse ECR methodologies. Employing a suite of electrochemical techniques including potentiodynamic polarization, linear resistance polarization, cyclic voltammetry, and chronopotentiometry, the investigation reveals useful insights. The findings show that among the tested amines, CO2-rich monoethanolamine (MEA) exhibits the highest corrosion rate. However, in most cases the rates remain within tolerable limits for ECR operations. Primary amines, notably monoethanolamine (MEA), show enhanced compatibility with ECR processes, attributable to their resistance against carbonate salt precipitation and sustained stability in potential over extended durations. Conversely, tertiary amines such as methyldiethanolamine (MDEA) present challenges due to the formation of carbonate salts during ECR, impeding their effective utilization. The study highlights the effectiveness of pulse ECR strategies in stabilizing ECR. A noticeable shift in cathodic potential and reduced deposit formation on the catalyst surface through periodic oxidation underscores the efficacy of such strategies. These findings offer insights for optimizing ECR in amine media, thereby providing promising pathways for advancements in CO2 emission reduction technologies.

The nickel-chromium-molybdenum alloy 625 exhibits an excellent combination of mechanical properties and corrosion resistance. However, the high temperature plastic deformation process and the heat treatment represent critical aspects and the adoption of non-optimal parameters can result in excessive grain coarsening and loss in mechanical strength. This detrimental behavior is worsened by the presence of a narrow region of temperatures and strain rates for complete recrystallization and the absence of phase transformation temperatures. In this alloy, the presence of sufficient amounts of niobium, titanium and aluminum permits slow age-hardening response upon single-aging treatments. Therefore, when the soft- or solution-annealed condition is associated with insufficient mechanical properties, this potentiality can be exploited to improve the mechanical strength and prevent waste of material and resources. Since the precipitation kinetic of the hardening γ^'' phase can be accelerated by prior nucleation treatment, different time-temperature combinations of double aging at 732 °C and 621 °C are investigated to reduce the overall heat treatment time. However, the simultaneous formation of Cr-rich carbides can dramatically affect the intergranular corrosion resistance. For this reason, a performance map is developed to compare all the tested conditions and identify the best compromise in terms of mechanical strength and corrosion rate.

A new Mg-Zn-Zr-Ca alloy in powder state was obtained via mechanical alloying method, from pure elemental powder. Further, the obtained powder-alloy was processed by selective laser melting (SLM) procedure to obtain 3D printed samples for small biodegradable implants. A series of microstructural, mechanical and corrosion analysis were performed. The SEM analysis of powder-alloy reveal a good dimensional homogeneity, with uniform colored, no agglutinated and almost rounded particles, suitable for selective laser melting procedure. Further, the SLM samples reveal a robust and unbreakable morphology, with a suitable porosity and without undesirable balling effect. The tested Young’s modulus of the SLM samples, of 42 GPa, is close to cortical bone one, of 30 GPa. The corrosion tests performed in PBS (Phosphate-buffered saline) solution show that the corrosion parameters have a satisfactory evolution.

This study investigates the effects of Zinc (4wt.%) and severe plastic deformation on the mechanical properties of AZ61 magnesium alloy through the stir-casting process. The severe plastic deformation (equal channel angular pressing (ECAP)) has been done followed by T4 heat treatment. The microstructural examinations revealed that the addition of 4wt.%Zn enhances the uniform distribution of β-phase, contributing to a more uniformly corroded surface in corrosive environments. Additionally, dynamic recrystallization (DRX) significantly reduces the grain size of as-cast alloys after undergoing ECAP. The attained mechanical properties demonstrate that after a single ECAP pass, AZ61 + 4wt.%Zn alloy exhibits optimal yield strength (YS), ultimate compression strength (UCS), and hardness. This research highlights the promising potential of AZ61 + 4wt.%Zn alloy for enhanced mechanical and corrosion-resistant properties, offering valuable insights for applications in diverse engineering fields.

it still undergoes corrosion when exposed to corrosive environments. This paper proposes an evaluation method for assessing the corrosion level of SPCC steel specimens using traditional eddy current testing (ECT), along with two different machine learning approaches. The objective is to classify the corroded state of the specimens into two states: a less corroded state (state-1) and a highly corroded state (state-2). Generative and discriminative models were implemented for classification. The generative classifier was based on the Gaussian mixture model (GMM), while the discriminative model was based on the logistic regression model. The models used features based on the absolute maximum of the perturbation magnetic field components at two different frequencies. The performance of the classifiers was evaluated using metrics such as absolute error, accuracy, precision, recall, and F1 score. The results indicate that high classification accuracy can be achieved based on both methods using traditional eddy current testing.

This study introduces a novel nanocomposite coating composed of PANI/CeO2 nanocomposite films, aimed at addressing corrosion protection needs. Analysis through FTIR spectra and XRD patterns confirms the successful formation of the nanocomposite films. Notably, the PANI/CeO2 nanocomposite films exhibit a hydrophilic nature. The bandgap energy of the PANI composite film measures at 3.74 eV, while the introduction of CeO2 NPs into the PANI matrix reduces the bandgap energy to 3.67 eV. Furthermore, the electrical conductivity of the PANI composite film is observed to be 0.40 S.cm-1, with the incorporation of CeO2 NPs leading to an increase in electrical conductivity to 1.07 S.cm-1. To evaluate its efficacy, electrochemical measurements were conducted to assess the corrosion protection performance. Results indicate a high protection efficiency of 92.25% for the PANI/CeO2 nanocomposite film.

Marked changes in temperature, pH, dissolved oxygen (DO) content, and nutrient content typically occur in marine thermoclines, which are key factors that affect the corrosion of metals. Offshore platforms have required marine metals to be exposed to deep-sea environments and have thus increased their penetration into the marine thermocline. This study investigates the galvanic corrosion of E690 steel in a marine thermocline using a simulated marine thermocline (SMT). Specifically, the corrosion of E690 steel was analyzed using the wire beam electrode (WBE) technique, linear polarization (LP), corrosion morphology, and weight loss measurement. Results indicated that the SMT had a stable multilayer structure, and the variations of temperature, DO, pH and nutrient concentration in the SMT were similar to those in the natural marine thermocline. Galvanic corrosion occurred after the intrusion of E690 steel into the marine thermocline. The driver of galvanic corrosion was the of E690 steel at various depths of the marine thermocline. The Ecorr of E690 steel was influenced by the temperature, pH and DO of seawater, and the order was DO >> T > pH. The continuous reduction of Ecorr with depth contributed to the large-scale galvanic corrosion, and the oscillation variation of Ecorr with depth was the reason for small-scale galvanic corrosion. The primary anodic regions of galvanic corrosion were located in the area with the fastest temperature variation in the thermocline. The proportion of galvanic corrosion in the average corrosion rate could increase up to approximately 80% in the stable anodic region. There were many deep corrosion pits in the long-term and stable anodic region of galvanic corrosion.

Modern engineering faces challenges in ensuring technical standards for service, durability, and sustainability. Political, administrative, and budgetary factors, coupled with climate change, pose tasks to structural integrity, affecting industries and economies. Marine infrastructures represent a strategic asset of the country as it handles a large part of the economic exchanges. This article analyzes five essential factors that play a fundamental role in the performance analysis of coastal structures: Chloride-induced corrosion, degradation models, maintenance strategies, monitoring, and climate change. Starting with reinforcement corrosion, considered as the main cause of distress, particularly in coastal zones for the long-term behavior of structures. Additional pressure from the influences of climate change is becoming evident and extreme, leading to reduction in capacity. To guarantee the lifespan, degradation models contribute by estimating the long-term performance of the asset as a strategic piece to the development of effective maintenance solutions. Additionally, quantifying the condition of the structure from monitoring data, plays a crucial part that provides information on the current situation of the structure. Finally, this review summarizes the challenges associated with the maintenance of aging marine structures considering aspects such as corrosion, monitoring, and the future challenges this area will face due to climate change.

The current economic development paradigm, which is based on steadily rising resource consumption and pollution emissions, is no longer viable in a world with limited resources and ecological capacity. The "green economy" idea has presented this context with a chance to alter how society handles the interplay between the environmental and economic spheres. The related concept of "green nanotechnology" aims to use nano-innovations within the fields of materials science and engineering to generate products and processes that are economically and ecologically sustainable, enabling society to establish and preserve a green economy. Many different economic sectors are anticipated to be impacted by these applications, including those related to corrosion inhibitor nano fertilizers, nano remediation, biodegradation, heavy metal detection, biofuel, insecticides & pesticides, and catalytic CO2 reduction. These innovations might make it possible to use non-traditional water sources safely and to create construction materials that are enabled by nanotechnology, improving living and ecological conditions. Therefore, our aim is to highlight how nanotechnology is being used in the green economy and to present promises for nano applications in this domain. Additionally, we want to critically examine the practical difficulties these applications raise, especially in consideration of any possible implications for the health and safety of those employed within this innovative sector. In the end, it emphasizes how critical it is to attain a really sustainable advancement in nanotechnology.

This article utilized electrodeposition technology to fabricate Zn and Zn-Y₂O₃-Al₂O₃ composite coatings on Q235 steel plates. The composite coatings were obtained by adding Y₂O₃/Al₂O₃ nanoparticles (0, 5, 10, and 15 g/L) to acidic chloride solutions. This study then examined the impact of these nanoparticles on the microstructure, morphology, microhardness, hydrophobicity, and corrosion resistance of the composite coatings. The results indicate that the addition of the nanoparticles increased the nucleation sites on the surface of the coating, thereby refining the grain size and reducing the roughness of the coating surface. When 10g/L of Y₂O₃ and 10g/L of Al₂O₃ nanoparticles were added, the hardness of the composite coating (369 Hv) was 2.49 times higher than that of the pure Zn coating (148 Hv), which was attributed to the dispersion strengthening and grain refinement effects of the nanoparticles. The corrosion resistance of the Zn and Zn-Y₂O₃-Al₂O₃ composite coatings was studied using linear sweep voltammetry and AC impedance spectroscopy. The addition of the nanoparticles improved the corrosion resistance of the composite coating, and the composite coating prepared in an electrolyte containing 10 g/L of Y₂O₃ and 10 g/L of Al₂O₃ nanoparticles exhibited the best corrosion resistance. Meanwhile, the composite coating exhibited good hydrophobicity, with a contact angle of 120.9°, 1.94 times that of the pure Zn coating (62.2°). The Zn-Y₂O₃-Al₂O₃ nanocomposite coating material has significant potential advantages in the field of steel corrosion.

The 70/30 copper–nickel alloy is mainly used in critical parts with more demanding conditions in marine settings. There is a need for innovative methods that offer fast production and cost-effectiveness to supplement current copper–nickel alloy manufacturing processes. In this study, we employ wire-arc additive manufacturing (WAAM) to fabricate the 70/30 copper–nickel alloy. The as-built microstructure is characterized by columnar grains with prominent dendrites and chemical segregation in the inter-dendritic area. The aspect ratio of the columnar grain increases with increasing travel speed (TS) at the same wire feed speed (WFS). This is in contrast to an equiaxed grain structure with a more random orientation of conventional sample. The sample built with a WFS of 8 m/min, TS of 1000 mm/min, and a track distance of 3.85 mm exhibits superior corrosion properties in the 3.5 wt% NaCl solution compared to the conventional one, as evidenced by a higher film resistance and breakdown potential, along with a lower passive current density of the WAAM sample. The corrosion morphology reveals the critical roles played by the nickel element unevenly distributed between the dendrite core and inter-dendritic area.

The use of disinfectants, particularly those containing quaternary ammonium compounds (QUACs), has dramatically escalated globally since the coronavirus disease 2019 pandemic. We report a case that highlights the risks associated with the ingestion of a low-concentration QUACs solution and emphasizes the importance of effective management in resolving severe lesions without sequelae. A 17-month-old boy experienced severe respiratory failure after ingesting a disinfectant containing benzalkonium chloride (BAC). The child was initially treated in a local emergency department and was subsequently transferred to a pediatric poison center. Upon evaluation, the child was found to have grade III-A corrosive esophageal lesions and chemical pneumonitis. Several complications, including massive pneumothorax and candidemia, occurred during the clinical course of the disease. However, with timely medical intervention and appropriate supportive care, the patient completely recovered without any long-term sequelae. The properties of BAC and a comprehensive management approach may have been responsible for the patient's full recovery despite the potential life-threatening effects of the ingestion of disinfectants.

In this work, electrochemical deposition (galvanostatic and potentiostatic) techniques were used to obtain of new composite polymer: 3-methylpyrrole - sodium dodecyl sulfate/poly 2-methythiophene (P3MPY-SDS/P2MT) coatings on cobalt -based alloy sample for anticorrosion protection. The sodium dodecyl sulfate as a dopant ion used in electropolymerization practice can have a relevant effect at the anticorrosion protection of the composite polymer layer by blocking the entry of aggressive ions. The cobalt -based alloy substrate had an important influence on the electrochemical performance of the composite coating and this together with the presence of the polymeric layer was achieved by simultaneously formation of a complex oxides film and polymeric layers. The polymeric coatings were analyzed by cyclic voltammetry, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) methods. The corrosion protection of P3MPY-SDS/P2MT coated cobalt based alloy has been explored by potentiostatic and potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) procedures in1 M HCl medium. The corrosion establishment of P3MPY-SDS/P2MT covered cobalt based alloy was observed to be ~10 times less than that uncoated specimen and the effectiveness of these composite layers of this coating is above than 90%. The superior efficacy is achieved by the electrochemical polymerization of P3MPY-SDS/P2MT obtained at 0.5 mA/cm2 and 1mA/cm2 current densities and at 0.9V and 1.0V potential applied and in molar ratio 5:1. Corrosion tests result indicated that P3MPY-SDS/P2MT coatings provide good corrosion protection of cobalt -based alloy in aggressive environments.

Diatomite (DME) consists of natural ordered porous structures that are excellent candidates as microcontainers. However, to the best of our knowledge, the application of DME loaded with corrosion inhibitors in anti-corrosion coatings has not hitherto been reported. In this study, DME has been used as a source of microcontainers to load benzotriazole (BTA) inhibitor by an immersion method. In order to prevent unwanted early release of the small molecule BTA inhibitor from the DME microcontainers, inspired by the adhesion characteristics of catechol and amine in mussel adhesion protein, polydopamine (PDA) was coated on their surfaces to generate BTA@DME/PDA microcapsules. Because of the depolymerization characteristics of PDA at low pH, the synthesize microcapsules showed a controllable release function. The SEM morphology, chemical structure, and loading capacity of the synthesized BTA@DME/PDA microcapsules were characterized. The corrosion resistances of epoxy coatings with different contents of BTA@DME/PDA microcapsules were compared by saline immersion and electrochemical impedance tests. A scratched coating with 5wt.% BTA@DME/PDA microcapsules showed the best anti-corrosion effect.

In the previous work, the pure fatigue behavior of AM60 magnesium alloy (PF-AM60) was compared with the corrosion fatigue behavior of these specimens (CF-AM60). In this research, in continuation of the previous job, the pure fatigue behaviors of AM60 with polylactic acid (PLA) coating (PF-AM60-PLA) and also, corrosion fatigue behaviors of magnesium alloy with PLA coating (CF-AM60-PLA) were evaluated. Polymer coating was made by fused deposition modeling (FDM) with a 3D printer and attached to standard fatigue test specimens with a glue. Then, they were immersed in the simulated body fluid (SBF) for 27 days. In the end, a high-cycle bending fatigue test was performed on samples. The fracture surface of the samples was also observed using the field emission scanning electron microscopy (FESEM). Due to corrosion, the weight of the specimens redcued by an average of 35%. The corrosion rate decreased in the first 7 days and then increased. PF samples with coating had an average of 49% increase in fatigue lifetime. Regarding the CF samples, despite the use of a 10 times stronger solution, the fatigue lifetime of these samples decreased by only 35%. FESEM results also showed cleavage plates and striations. In addition, the separation of the glue from the coating and Mg was observed. Corrosion products including microcracks and holes were seen on the fracture surface of CF specimens, which caused stress concentration and crack growth. Holes caused by the release of gases were also observed in polymer coatings.

The silane (3-Aminopropyl)triethoxysilane (APTES), possesses one terminal amine group and three ethoxy groups extending from each silicon atom, serving as a crucial interface adherent between organic and inorganic materials. In corrosion prevention, APTES is frequently employed as a primer, with subsequent topcoat as an extra protective layer. This topcoat is particularly useful in covering sites where APTES may exhibit poor bonding, such as those involving Cu or Cu-rich alloying elements. In our study, we applied a thin layer of APTES to cleaned AA2024-T3 samples using concentrated vapor deposition, followed by spin-coating with a diluted PS/acetone solution. Through combinatorial experimentation, we investigated the impact of APTES on the corrosion resistance of the coating system on AA2024-T3. Our findings indicate that a higher surface energy of the APTES primer contributes to better corrosion resistance in the overall coating system. This improvement can be attributed to enhanced wettability achieved by the PS/acetone solution on the cured APTES primer, leading to a more uniform coverage of the dried PS topcoat. Additionally, our research revealed that, in the early stages of exposure to the corrosion solution, a thinner APTES primer enhances protection against corrosion. This effect is attributed to hydrolytic stability mechanisms, and the interactions between hydrolyzation/condensation in soaked APTES and the dissolution of naturally formed aluminum oxide pre-existing in the bare samples. Finally, we observed that an APTES primer subjected to additional heat treatment before topcoating exhibits superior performance in corrosion resistance.

Conventional heat treatment is not capable of converting a sufficient amount of retained austenite into martensite in high-carbon or high-carbon and high-alloyed iron alloys. Cryogenic treatment induces the following alterations in the microstructures: (i) a considerable reduction in the retained austenite amount, (ii) formation of refined martensite coupled with an increased number of lattice defects, such as dislocations and twins, (iii) changes in the precipitation kinetics of nano-sized transient carbides during tempering, and (iv) an increase in the number of small globular carbides. These microstructural alterations are reflected in mechanical property improvements and better dimensional stability. A common consequence of cryogenic treatment is a significant increase in the wear resistance of steels. The current review deals with all the mentioned microstructural changes as well as the variations in strength, toughness, wear performance, and corrosion resistance for a variety of iron alloys, such as carburising steels, hot work tool steels, bearing and eutectoid steels, and high-carbon and high alloyed ledeburitic cold work tool steels.

The study’s objective is to analyse the mechanical properties of steel pipe piles as a part of a trestle bridge subjected to five years of natural marine corrosion degradation. Sixteen tensile specimens were extracted from the steel pipe piles in the splash, tidal, and immersion zones. The experimental tensile test results are used to establish regression equations defining elastic modulus, yield strength, strain hardening index, and strength coefficient for the true stress-strain curves of the three regions. A non-linear time-dependent mathematical model is exploited to identify the corrosion degradation using the data from one single corrosion degradation measurement campaign. The analysis indicated that the splash zone experiences the most severe corrosion degradation, and there are progressive losses in the mechanical properties of each zone as the corrosion degradation progresses. The established relationships of the mechanical properties, as a function of the ratio of corroded plate thickness to the as-built one, can be used as a fast-engineering approach to identify the mechanical properties of severely corroded piles. The corrosion degradation allowance is also defined using the First Order Reliability Method, accounting for existing uncertainties covered by the partial safety factors. By examining the impact of marine corrosion on the mechanical properties of marine structures and developing predictive models to assess the corrosion’s effect on material strength and corrosion allowance, the study aims to improve offshore structures’ safety, design, and maintenance.

The development of Al-Ni alloys with a controlled microstructure has had a great impact on the field of study of aluminum-based alloys. In the present research, the influence of thermal parameters on the grain structures resulting from the directional solidification process of Al-Ni alloys with different alloy content has been studied. It has also been evaluated how different structures and the distribution of second phases influence the corrosion behavior and microhardness of alloys. The columnar-to-equiaxed transition (CET) was observed to occur when the temperature gradient in the melt decreased to values between 1.3 to 2.9 ° C/cm. In addition, a small increase in the microhardness values was observed as a function of the Ni-content. When the Ni-content increase, the resistance to polarization decreases for samples with equiaxed grain structure, throughout the range of compositions studied. Furthermore, the equiaxed grain structure presents higher resistance to polarization values than the columnar grain zone, for alloys with a composition equal to or lower than the eutectic composition.

Sr4Al6O12SO4 samples were obtained from the compound mixture formed by a solid–state reaction of Al2O3, SrSO4, and SrCO3. Samples were compacted at 100MPa to form pellets of 1 and 4cm in diameter and were sintered at 1400°C for 4 hours. The compound was analyzed by X–ray diffraction. Static immersion and wettability tests were performed to evaluate corrosion resistance in contact with Al–Si. Corrosion tests were carried out by immersion at 800, 900, and 1000°C for 24, 50, and 100 hours, while wettability was carried out at 900, 1000, and 1100°C for 2 hours. Subsequently, the samples were prepared metallographically. Samples were analyzed by optical microscopy, scanning electron microscopy, and image analysis. In general, reaction products consisting of alumina, spinel, oxides, and sulfates were found. The contact angles obtained were 124° to 135°. It is concluded that ceramic substrate Sr4Al6O12SO4 is resistant to corrosion by Al–Si alloy, since the slight thickness of the reaction products found in the samples (100μm) considering the severe conditions of the experiment: 1000°C and 100 hours of isothermal temperature. Furthermore, it can be said that Sr4Al6O12SO4 is not wettable by Al–Si alloys.

Magnesium alloy stents have been extensively studied in the field of biodegradable metal stents due to their exceptional biocompatibility, biodegradability and excellent biomechanical properties. Nevertheless, the specific in vivo service environment causes magnesium alloy stents to degrade rapidly and fail to provide sufficient support for certain time. This paper presents an overview of the development history and protection strategies for magnesium alloy stents. Alloying, optimizing stent structure and preparing protective coating have improved the corrosion resistance of magnesium alloy stents. Based on the corrosion mechanism of magnesium alloy stents, as well as their deformation during use and environmental characteristics, we present some novel solution strategies aiming at reducing the corrosion rate of magnesium alloys and enhancing the comprehensive performance of magnesium alloy stents. These strategies include adapting protective coatings for the deformation of the stents, preparing rapid endothelialization coatings to enhance the service environment of the stent, and constructing coatings with self-healing functions. It is hoped that this review can help to understand the development of magnesium alloy cardiovascular stents and solve the problems related to magnesium alloy stents in clinical applications at the early implantation stage.

In this study, Fe-Mo-B based hardfacing electrodes containing different amounts of Mo were coated on an AISI 1020 steel substrate using the electric arc welding method. The findings show that molybdenum is highly effective on the microstructure and minor changes in the coating composition affect the phases and morphological properties. In the hardness tests, an increase of 73% was achieved in the Fe14Mo2B4 based hardfacing coating compared to the base material and a 30% increase compared to the Fe16B4 based coating. The highest macro hardness value was measured as 56.4 HRC and the highest phase hardness was measured as 3228 HV in the FeMo2B2 phase. The lowest wear rate was measured in the Fe14Mo2B2 based coating. The wear rate of the Fe14Mo2B4 based coating was 8.1 times lower than that of the substrate material and 4.7 times lower than that of the Fe16B4 based coating. According to corrosion test results, the highest corrosion resistance was obtained in Fe16B4 based coating. The current density value of the Fe16B4 based coating was measured to be 13.6 times lower than that of the substrate material.

The effects of organic metabolites produced by a sulfate-reducing prokaryote (SRP) in seawater on the anode corrosion process of magnesium alloy were analyzed by open circuit potential, electrochemical impedance spectroscopy, polarization curve, and other electrochemical methods, combined with scanning electron microscopy and X-ray diffraction. It was found that the product film produced by magnesium alloy anode corrosion was not dense, and the surface of the magnesium anode substrate was exposed during the corrosion process. The corrosion of magnesium anode matrix was accelerated by the simulation of different organic metabolites including mannose, glucuronic acid, and glucose. Thus, the synergistic effect of various metabolites produced by SRP in the corrosion process of magnesium alloy may be considered in future studies.

In this study, the effect of increasing exposure time on microstructures, defectiveness, mechanical properties and corrosion behavior of selective laser melted sample Al-Si10-Mg powder have been investigated. The sample were processed at the same power (375 W) and scan speed (2000 mm/s) but with increasing exposure time. Exposure time equal to 40, 50 and 60 µs was applied. The features of the analyzed samples show that with increasing exposure time a better efficiency of the heat input has been obtained with larger size of melting pool and Si particles and lower defectiveness. Moreover, being the coarser microstructure associated a to lower level of voids, the average hardness is similar for the analyzed samples. The potentiodynamic curves of the samples show that the voids occurrence is more significant with respect to the scale of micro-structure on corrosion behavior being the sample processed at the highest exposure time the more resistant to corrosion. The experimental techniques used in the present study were Optical microscope, Sem microscope, Hardness and X-Ray Computed Tomography.

The widespread use of epoxy resin (ER) in industry, owing to its excellent properties, aligns with the global shift toward greener resources and energy-efficient solutions, where utilizing metal oxides in 3D printed polymer parts can offer extended functionalities across various industries. ZnO concentrations in polyurethane acrylate composites impacted adhesion and thickness of DLP samples, with 1 wt.% achieving a thickness of 3.99±0.16 mm, closest to the target thickness of 4 mm, while 0.5 wt.% ZnO samples exhibited the lowest deviation in average thickness (±0.03 mm). Tensile strength in digital light processed (DLP) composites with ZnO remained consistent, ranging from 23.29 MPa (1 wt.%) to 25.93 MPa (0.5 wt.%), with an increase in ZnO concentration causing a reduction in tensile strength to 24.04 MPa and a decrease in the elastic modulus to 2001 MPa at 2 wt.% ZnO. The produced DLP samples, with their good corrosion resistance in alkaline environments, are well-suited for applications as protective coatings on tank walls. Customized DLP techniques can enable their effective use as structural or functional elements, such as in Portland cement concrete walls, floors and ceilings for enhanced durability and performance.

This study delves into the atmospheric corrosion behavior of chromium-free complex-phase steel (CP), specifically investigating the influence of wet/dry frequency and ratio in cyclic corrosion tests (CCT). The study employs a modified ISO 14993 standard CCT method, which involves salt spray, dry, and wet stages. After 15 and 30 CCT cycles, mass loss, maximum corrosion depth, and corrosion products were analyzed to gain insights into corrosion mechanisms. In general, increasing the frequency and wet/dry stage ratio in CCT extends the time for autocatalytic reactions to occur, leading to accelerated localized CP corrosion and increased pitting factors. However, as the rust layer thickens, uniform corrosion may also intensify, so careful considerations are necessary. This study underscores the importance of controlling the frequency and ratio of wet/dry stages in CCT for effectively analyzing localized corrosion behavior in specimens.

The present work analyzes the behavior in terms of corrosion resistance of three reinforced concrete formulations over a period of 1 year. The samples were accompanied by creating a monitoring methodology using the Electrochemical Impedance Spectroscopy (EIE) technique, working only with the real component over time. Three mixtures were used, one conventional without pozzolanic addition (REF) and two others with pozzolanic additions, rice husk ash (RCA) and metakaolin (MK). Prototypes were created and exposed to the action of a 165g/l NaCl sodium chloride solution. The characterization of the materials was carried out by determining the chloride diffusion profile (ASTM 1556), analyzing images using tomography and with the support of analytical techniques such as x-ray fluorescence and x-ray diffraction. The monitoring methodology using the EIE demonstrated the positive effect of the insertion of pozzolans, rice husk ash (RCA) and metakaolin (MK), by delaying the process of chloride diffusion in the concrete, resulting in greater resistance to corrosion. The EIE also showed that the active mineral addition in concrete, of aluminum-silicic composition (MK), had a predominant protective effect on the steel//concrete interface against the attack of chloride ions.

Two austenitic stainless steel (ASS) plates, 304L and 316L, were cold-rolled (304R and 316R) with a 10 % reduction in thickness then subjected to laser welding. Cold-rolling caused a slight surface hardening and introduced residual tensile stress into the ASS plates. The susceptibility to stress corrosion cracking (SCC) of the welds (304RW and 316RW) was determined using the U-bend test pieces in a salt spray. To highlight the stress concentration at the weld’s fusion boundary (FB), the top weld reinforcement was not ground off before bending. Moreover, micro-shot peening (MSP) was performed to mitigate the SCC of the welds by imposing high residual compressive stress and forming a fine-grained structure. Cold-rolling increased the susceptibility of the 304R specimen to pitting corrosion (PTC) and intergranular (IG) microcracking. Moreover, PTC and SCC were found more often at the FBs of the 304RW. The corrosion pits of the peened 304RW (304RWSP) were finer but greater in amount than the un-peened one. The results also indicated that the 316L ASS welds with MSP was resistant to the incidence of PTC and SCC in a salt spray. The better reliability and longer service life of dry storage canister could be achieved by using 316L ASS for construction and application of MSP on it.

Geothermal energy is likely to be a significant contributor in achieving sustainable energy goals and net-zero emissions targets. Within geothermal power plants, heat exchangers play a critical role in harnessing this renewable energy source. However, these heat exchangers encounter significant challenges when exposed to geothermal fluids, including erosion, corrosion, and scaling, which adversely affects their performance and longevity. The current review focuses on surface engineering techniques, particularly coatings, as a highly effective and economically viable solution to address these challenges in geothermal heat exchangers. The review begins by providing an overview of geothermal energy, its significance in the context of sustainability and the important role played by heat exchangers in geothermal power generation, followed by the challenges and their impact on heat exchangers. The subsequent section focuses on surface engineering by coatings and its types employed to enhance the performance of heat exchangers. In the final part, the reader is presented with an overview of the challenges associated with the application of coatings in geothermal heat exchangers and potential future directions in this field. This review offers a detailed understanding of the critical role coatings play in improving the efficiency and service life of heat exchangers in geothermal power plants.

Several factors impact the durability of concrete bridge decks, including traffic loads, fatigue, temperature changes, environmental stress, and maintenance activities. Detecting problems such as corrosion, delamination, or concrete degradation early on can lower maintenance costs. Nondestructive evaluation (NDE) techniques can detect these issues at early stages. Each NDE method, meanwhile, has limitations that reduce the accuracy of the assessment. In this study, multiple NDE technologies were combined with machine learning algorithms to improve the interpretation of half-cell potential (HCP) and electrical resistivity (ER) measurements. A parametric study was performed to analyze the influence of five parameters on HCP and ER measurements, such as degree of saturation, corrosion length, delamination depth, concrete cover, and moisture condition of delamination. The results were obtained through finite element simulations and used to build two machine learning algorithms, a classification algorithm and a regression algorithm, based on the Random Forest methodology. The algorithms were tested using data collected from a bridge deck in the BEAST® facility. Both machine learning algorithms were effective in improving the interpretation of ER and HCP measurements using data from multiple NDE technologies.

Wirobond C is a commercial dental casting alloy suitable for the fabrication of crowns, bridges as well as metal-ceramic restorations. This work aims with the study of the effect of ready-to-use Listerine® and Meridol® mouthwashes and sodium fluoride on corrosion resistance of the CoCrMo dental alloy to electrochemical corrosion in artificial saliva at 37 °C. SEM, EDS, SKP, and microhardness investigations were carried out to characterize the material under study. In vitro corrosion resistance of the CoCrMo alloy was conducted by the open circuit potential method, electrochemical impedance spectroscopy, and anodic polarization curves. The presence of Co 59.8(8) wt.%, Cr 31.5(4) wt.%, and Mo 8.8(6) wt.% was confirmed. The CoCrMo alloy was characterized by Vickers microhardness of 445(31) µHV0.3. Based on EIS data, the capacitive behavior and high corrosion resistance of CoCrMo alloy was revealed. The kinetics of pitting corrosion in the artificial saliva was lower after the modification with NaF and Listerine and Meridol mouthwashes. The potentiodynamic characteristics revealed the passive behavior of CoCrMo alloy in all solutions. Based on the SKP measurements of the CoCrMo alloy after corrosion tests, the effect of artificial saliva modification on electronic properties of Bego Wirobond C dental alloy was found.

The corrosion resistance of two cast CoCr based alloys, with different amounts of chromium and with different alloying elements in the bulk composition of the alloy, was assessed. Herewith, we investigated the corrosion behavior of Co21Cr8Mo7W and Co29Cr7W by open circuit potential (OCP), potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS) in 0.1 M phosphate buffer solution (PBS) at 37°C for long time immersion. After 1000 hours of immersion, the corrosion current density (icor), estimated from anodic polarization tests, is lower for Co21Cr8Mo7W (i.e. 49 nA cm-2) alloy compared to Co29Cr7W alloy (180 nA cm-2). As regards the corrosion potential (Ecor), a nobler value was observed for Co21Cr8Mo7W (i.e. -59 mV vs. Ag/AgCl) compared to Co29Cr7W (i.e. -114 mV vs. Ag/AgCl). These findings suggest a better corrosion resistance of the film formed on the alloy containing lower amount of Cr and two alloying elements, namely Mo and W. These results are promising ones in terms of medical applications because they open new strategies in obtaining alloys with lower content of chromium and with higher protective properties against corrosion attack.

In this paper we overview all analytical engineering solutions for corrosion problems in pressure vessels delivered over the past 60 years. We briefly detail strengths and weaknesses of existing approaches, thus demonstrating the need for novel uniform corrosion analysis methods for both current and new applications. To complement the review, we also present a new analytical model allowing to estimate the lifetime of pressured elastic vessels with mechanically assisted corrosion. Both internal/external pressure and internal/external corrosion are captured and dissolution driven corrosion is also considered. The readily implemented method improves existing analytical approaches and is shown to be effective for thin and thick shells, as well as various loading and corrosion intensity and geometrical conditions.

Chemical and mechanical properties of plasma-assisted nitrided (PAN), TiN cathodic arc coated, and PAN with TiN coated samples were thoroughly evaluated on tool steel samples of 1.2379. The evaluation involved SEM, nano-indentation, profilometer, micro scratch, and corrosion tests. The results revealed that PAN treatment alters the roughness of the surface, while it has minimal impact on the coefficient of friction. However, it increases the substrate's hardness, making it twice as hard and three times more resilient against scratch tests, along with improved corrosion resistance. TiN-coated samples are four times harder than untreated ones, but they exhibit a higher elastic modulus (E), leading to a lower H/E index. The most promising results were obtained with PAN+TiN treatment, combining high hardness (H) with lower E, resulting in a high H/E index, a crucial criterion for wear resistance. These samples also demonstrated superior scratch hardness and corrosion resistance, despite being thinner and rougher.

This paper presents an investigation of the oxidation of Alloy X-750 containing 5% Fe in a simulated boiling water reactor (BWR) environment. To mimic the conditions in which the bare metal is exposed to the reactor water the samples were not pre-oxidized. The specimens were exposed for durations ranging from 2 to 840 hours, and the development of the oxide microstructure was mainly studied using electron microscopy. The results showed that the oxide scale consisted of blocky crystals of trevorite on top of a porous inner layer rich in Ni and Cr. After the longest exposure time, the trevorite crystals completely covered the specimen surface. The study further revealed that the speed at which the oxide grew and the metal dissolved both decreased with time. Additionally, the metal thinning process was found to be sub-parabolic. Given the significant variation in iron content in the X-750 specification, the influence of this element on the material's corrosion performance in BWR was examined by comparing the results from this investigation with those from previous work on material containing 8 wt% Fe. The study demonstrated that the oxide growth, metal dissolution and metal thinning were slower in the material with higher Fe content, indicating the importance of this element in limiting the degradation of Alloy X-750 in BWR environments.

In this study, we investigated the effects of three surface treatment techniques on 316L stainless steel, low-temperature immersion corrosion, shot peening followed by immersion corrosion, and electrochemical corrosion. Surface alterations were analyzed using scanning electron microscopy, Raman spectroscopy, and α-step thin-film thickness profiling. Human osteoblast adhesion was evaluated using Liu’s stain and metallographic optical microscopy. The results revealed weak cell adhesion after low-temperature immersion and shot peening followed by immersion corrosion. By contrast, electrochemical corrosion, particularly with a high current density and low corrosive solution concentration, resulted in a uniformly corroded surface, thus promoting dense cell adhesion. All three techniques resulted in porous oxide layers. Overall, our experimental findings highlighted shot peening (1 kg/cm2 for 20 s) and electrochemical corrosion (0.5 M HCl) as effective processes. Electrochemical corrosion produced uniformly dense corrosion pits, whereas shot peening produced semicircular grooves with small corrosion pits, both favorable for cell adhesion. Electrochemical corrosion also yielded excellent cell adhesion, emphasizing its suitability for biomedical activity. We developed a process for creating a porous surface layer and thereby enhancing the cell adhesion to 316L stainless steel for potential biomedical implant applications.

Tungsten carbide inserts (TCI) and polycrystalline diamond compact (PCD) cutters used in two types of drill bits for drilling oil and gas wells were evaluated by a pin-on-disc test. The morphology of the worn surface was characterized by scanning electron microscopy (SEM). The behavior of corrosion resistance was evaluated with the electrodynamic polarization technique. The polycrystalline diamond compact cutter has a higher hardness, better corrosion, and wear behavior compared to tungsten carbide.

Although 4Ce4YSZ has high corrosion resistance, it faces challenges concerning sinterability and ionic conductivity. Therefore, we studied destabilization behavior caused by corrosion and oxygen vacancy ordering according to ZnO doping. The powders of (4Ce4YSZ)1-x(ZnO)x (x=0.5, 1, 2, 4 mol%) were synthesized through the sol-gel method. With the addition of ZnO, the cubic phase increased, and secondary phases were not observed. The (111) peak showed a higher angle shift in ZnO-doped 4Ce4YSZ compared to 4Ce4YSZ, and TEM-SAED revealed a reduction in the spacing of the (011)t plane, suggesting lattice contraction due to the substitution of the smaller Zn2+ (60 Å) for Zr4+ (84 Å) in the lattice. The local atomic structure analysis was conducted using EXAFS to investigate the oxygen vacancy ordering behavior. Zr K-edge Fourier-transform data revealed a decrease in the Zr-O1 peak intensity with an increasing amount o ZnO doping, indicating an increase in oxygen vacancies. The Zr-O1 peak position shifted to the right, leading to an increase in the Zr-O1 interatomic distance. In the Y K-edge Fourier-transform data, the Y-O1 peak intensity did not decrease, and there was little variation in the Y-O1 interatomic distance. These results suggest that the oxygen vacancies formed due to ZnO doping are located in the neighboring oxygen shell of Zn, rather than in the neighboring oxygen shells of Y and Zr. Impedance measurements were conducted to measure the conductivity, and as the amount of ZnO doping increased, the total conductivity increased, while the activation energy decreased. The increase in oxygen vacancies by ZnO doping contributed to the enhancement of conductivity and it is considered that these created oxygen vacancies did not interact with Zn2+ and did not form defect associations. Fluoride-based molten salts were introduced to the specimens to assess corrosion behavior in a molten salt environment. Yttrium depletion layers (YDLs) were formed on the surfaces of all specimens due to the leaching of yttrium. However, Ce remained relatively stable at the interface according to EDS line scans, suggesting a reduction in the phase transformation (cubic, tetragonal to monoclinic) typically associated with yttrium leaching in YSZ.

The regenerated magnesia-calcium brick samples that had added 0, 1.5, 3.0 wt.% aluminium oxide (Al2O3) were prepared by using spent magnesia-calcium bricks, fused magnesia and Al2O3 powder additive as the main raw materials. The phases, microstructures, room temperature and hot flexural strength, resistance to cement clinker corrosion and strength of coating adherence were investigated respectively. It indicated that the addition of Al2O3 increased mainly resulting in the content of tetracalcium aluminoferrite (C4AF) and tricalcium aluminate (C3A) increased in the regenerate samples. The bulk density, the room temperature flexural strength and the strength of coating adherence all increased, while the hot flexural strength and corrosion resistance both deteriorated along with the increase of Al2O3 addition. It was because that on the one hand the low melting point phases of C4AF and C3A improved the sinterability of the regenerated samples during the burning stage, on the other hand they melted or existed in liquid phase during the experimental temperature (1573 K and 1823 K) which degraded hot flexural strength and corrosion resistance, and enhanced the strength of coating adherence as the wettability of the liquid phase. The content of Al2O3 in the regenerated magnesia-calcium brick should not be higher than 1.1 wt.%, considering its room and high-temperature performances for cement rotary kiln.

This paper aims to determine the effect of local corrosion at three different corrosion areas, the 1. entire area, 2. constant moment area, and 3. constant shear area, on the flexural performance of RC beams. To analyze this, an experimental study was carried out to prepare two series of RC beams (200×300×2800mm) created with three different degree of corrosion inducing local rebar corrosion. Furthermore, two-series of experimental tests were conducted under different loading types by monotonic and cyclic loading. It was observed that strength capacity reduction grows in the order of the corroded RC specimens induced: the 1. entire area > 2. constant moment area > 3. constant shear area, as the average corrosion rate increases. Our test results further show that the yield and ultimate strength was kept nearly equivalent to the uncorroded RC specimen by the average corrosion rate of 10% and 15%, respectively. Over these corrosion rates, the yield strength and ultimate strength dropped significantly. Compared to test results under a monotonic loading condition, the structural capacity under a cyclic loading condition decreased with a more pronounced tendency for each corrosion case as the corrosion rate increased. A longitudinal crack was developed throughout and adjacent to the corrosion areas, as the corrosion rate increased. Thus, we can infer that strength reduction may be strongly influenced by this longitudinal crack.

The inner walls of drinking water distribution system (DWDS) are expected to be clean to ensure a safe quality of drinking water. In reality, complex physical, chemical and biological processes take place when water comes into contact with the pipe surface. This paper describes the impact of leaching different compounds from the water supply pipes into the drinking water and subsequent risks. Among these compounds there are heavy metals. It is necessary to prevent these metals to get into the DWDS. Those compounds are susceptible to impact the quality of the water delivered to population either by leaching dangerous chemicals into the water or by enhancing the development of microorganism growth on the pipe surface. The corrosion process of different pipes materials, scale formation mechanisms and the impact of bacteria formed in corrosion layers are discussed. Water treatment processes and the pipe materials also affect the water composition. Pipes materials act differently in the flowing and stagnation conditions. Also, they age differently (e.g metal based pipes are subjected to corrosion while polymer based pipes have a decreased mechanical resistance) and are susceptible to enhance bacterial film formation. This review helps to clarify what are the possible sources of compounds responsible for drinking water quality degradation. Also, it gives guidance on the measures that are needed to maintain a stable and safe drinking water quality.

In this study, the effects of various beryllium (Be) addition (Be-free, 0.1, 0.25, 0.50 wt.%) on the microstructure, mechanical properties, and corrosion corrosion of the Al-Mg-Li alloys were systematically investigated. The best performance was obtained in alloy with 0.1 wt.% Be addition. Trace Be addition promotes the grain refinement of the as-cast alloy ingot and contributes positive effects to the recrystallization, bringing improvement of tensile property. Meanwhile, the best anti-corrosion behavior is also presented at 0.1 wt.% Be addition, due to its potential to reduce the width of precipitates free zone (PFZ). As the Be content increase to an excessive level, the comprehensive performance decreases. Therefore, it is strongly recommended that adding trace Be element into Al-Mg-Li alloys has a positive effect on the comprehensive service performance.

The inhibition of localised corrosion is known to involve multiple processes taking place over a range of time and length scales that are difficult to study by conventional electrochemical methods. This work demonstrates an approach to probing complex localised electrochemical processes by combining an electrochemically integrated multi-electrode array (also known as wire beam electrode (WBE)), scanning vibrating electrode technique, scanning electrochemical microscopy and surface analytical techniques. Each technique reveals certain aspects of the dynamically changing, multi-scale, inhibitor-microstructure interactions and local chemistry over a heterogeneous AA2024-T3 alloy surface in the presence of an environmentally friendly inhibitor; cerium diphenyl phosphate (Ce(dpp)3).

The Voltammetric and polarographic methods are proposed to determine the short time corro-sion rates of brass in 1N HCl solution. It should be noted that it is also possible to determine the corrosion rates of each species present in the solution, simultaneously like Cu (II) and Zn (II) in brass. Samples extracted from bark of Babul (ESBB) is used as corrosion inhibitors. The corrosion inhibition efficiency is 96% at 24h after the test started. These results are compared with the av-erage corrosion rates obtained by using gravimetric (PIT) and some electrochemical methods i.e. galvanostatic and potentiodynamic polarization measurements.

A novel prediction model for crack development of reinforced concrete (RC) piles with localized chloride corrosion in marine environment is proposed. A discrete method is used to solve the corrosion pit radius model and a crack extension model is developed to investigate the initiation and extension of cracks. The maximum corrosion degree of reinforced concrete pile is predicted according to the limit crack criterion, and finally a sensitivity analysis is carried out on the important parameters of crack extension. The results show that the radius of corrosion pit, the depth corrosion pit and cross-sectional area loss of reinforcement gradually increase as the corrosion level increases. The loss of local reinforcement section at crack initiation decreases with the increase of the ratio of concrete cover to initial diameter, and increases with the increase of pitting factor. The required pit depth for reinforcement cracking increases with the increase of the ratio of concrete cover thickness to diameter. The loss of cross-sectional area of reinforcement and the radius of corrosion pit increase with the increase of initial diameter of reinforcement. Increasing the pitting factor will reduce the pit depth and make the crack width develop faster before reaching the limit crack width. Increasing the concrete cover thickness can provide an improvement in the propagation of cracks. A comparative analysis shows that the localized corrosion pattern is more in conformity with marine engineering practice.

Q345 steel is widely used in the construction industry, vehicle manufacturing industry, bridge construction industry and many other aspects due to its excellent comprehensive performance. However, due to its high silicon content, direct hot-dip galvanizing will lead to a series of problems, such as easy peeling of the coating due to the "silicon reactivity". In this paper, we adopt the "two-step hot-dipping method", first hot-dip aluminizing and then hot-dip galvanizing, to isolate the substrate and zinc liquid direct contact, so as to avoid the occurrence of "silicon reactivity". Through the microstructure characterization, neutral salt spray corrosion experiments, electrochemical experiments, the results show that: Al-Zn composite coatings from the inside out were perpendicular to the substrate growth of loose Fe2Al5 layer and Al-Zn layer, outbursts generation; Al-Zn composite coatings resistance to neutral salt spray corrosion was far more than the substrate; Al-Zn composite coatings polarization curve corrosion potential than the substrate was lower than that of the substrate by 0.512V, showing a strong corrosion resistance. It shows extremely strong corrosion resistance.

At present, in the field of aviation industry, titanium alloy is mainly used to manufacture parts such as compressor disc, blade and casing of aircraft engine. When working, titanium alloy parts produce high temperature due to high-speed running friction, which makes the high temperature oxidation resistance and friction resistance of titanium alloy greatly reduced. When their working environment contains salt, titanium alloys are subjected to thermal corrosion, which limits their wider practical applications. This paper introduce the aluminide coating and its preparation methods. The characteristics and functional mechanism of three functional coatings for service environment, such as high temperature resistant alumina-based coating, thermal corrosion resistant alumina-based coating and wear-resistant alumina-based coating are summarized. Finally, the development direction of composite coatings of titanium and titanium alloys for complex service environment is prospected.

Stray currents can cause very rapid degradation and material loss at the points where the current leaves the metal and enters the electrolyte. Nowadays, many resources are invested in the protection of jeopardized structures, such as buried pipelines, from stray current corrosion. This paper describes the measures that need to be considered in the design and construction of track structures to ensure high rail-to-ground resistance and consequently reduce stray currents. The main conclusions from existing guidelines and standards for reducing and controlling stray currents that are applied by various track operators are presented in the paper. Rail-to-ground resistance in different types of tracks structures and rail fastening systems is analysed and optimal type of the track and type of the fastening system is defined. The grounding schemes used on the tracks and their influence on stray current values are described, as well as the influence of traction power substation and rail cross bonding on stray current. Since it is not necessary to apply all the measures described to the same track structure, the paper gives recommendations on which measures to apply when building tracks with continuously fastened rails and which to apply when building tracks with discretely supported and fastened rails.

A huge part of corrosion failures and even of catastrophes takes origin from a trivial mistake in either choice or connection of different materials, as well as from an inaccurate evaluation of the compatibility between materials an environment. The example shown in the present paper summarizes several wrong solutions due to the lack of knowledge of the basic rules of corrosion control. By chance, either the consequences of such mistakes were so precocious that it was possible to find a remedy during the construction, or they were happily so venial as to be tolerated. This paper is third in a series devoted to enhancing the need of a professional corrosion control design for infrastructures.

The development and qualification of CrAlN coatings deposited by DC magnetron sputtering offer new industrial solutions to increase the lifecycle of material forming tools (machining and shaping). This study focuses on the selection and optimization of deposition modes for CrAlN layers to be deposited on a 90CrMoV8 tool steel substrate. The adopted methodology aims to optimize the deposition conditions to meet the customer's requirement of a CrAlN coating thickness of approximately 2-3 µm for use in a hot forming process. Different polarizations using two Al and Cr targets, with both stationary and rotating substrate modes during deposition, were tested and evaluated. Characterizations of the CrAlN coating layers (microhardness, residual stress, structures) and performance in service (wear, friction, adhesion, corrosion) were chosen as selection criteria for a particular coating mode. The aluminum content plays a crucial role in the tribological and mechanical behavior of CrAlN layers. Corrosion resistance is more sensitive to the aluminum content for the stationary deposition mode. As a result, the rotating mode provides higher adhesion (+100%) and less wear (-60%) compared to the stationary mode. Therefore, depending on the likely performance in service, either a stationary or rotating mode could be applied for coating the functional surfaces of hot forming tools.

This research aimed to improve the interpretation of electrical resistivity (ER) results in concrete bridge decks by utilizing results from multiple nondestructive evaluations (NDE) techniques in machine learning algorithms. To achieve this, a parametric study was first conducted using numerical simulations to investigate the effect of various parameters on ER measurements, such as the degree of saturation, corrosion length, delamination depth, concrete cover, and the moisture condition of delamination. A data set from this study was used to build a machine-learning algorithm based on the Random Forest methodology. This algorithm was then implemented on data collected from a bridge deck in the BEAST® facility. The presented results demonstrate an improvement in the interpretation of ER measurements using data from other NDE technologies.

In this work, the inhibition properties of new bio-based lignine ILs on the corrosion of mild steel in an aqueous solution of 0.01 M NaCl were investigated by Potentiostatic Electrochemical Impedance Spectroscopy (PEIS), Cyclic Potentiodynamic Polarization (CPP). Moreover, the surface was characterized using SEM, EDS, and optical profilometry. The influence of cation and anion on the inhibitor properties and a possible synergistic effect were investigated. The IL choline syringate showed a promising performance, reducing the corrosion current after 24-hour immersion in 0.01 M sodium chloride, from 1.66 µA/cm2 for the control to 0.066 µA/cm2 with 10 mM of the IL present. In addition to the performance as a corrosion inhibitor, both components of this IL also meet or exceed current additional desired properties of such compounds, being readily available, economically efficient, and well tolerated in organisms and the environment.

On-stream inspections are the most appropriate method for routine inspections during plant operation without going through production downtime. Ultrasonic inspection, one of the on-stream inspection methods, faces challenges when performed at high temperatures exceeding the recommended 52°C. This study aims to determine the ultrasonic velocity and attenuation with the known material grade, thickness, and temperatures by comparing theory calculation versus experiment with temperatures ranging between 30°C to 250°C on low carbon steel covering most petrochemical equipment material and working conditions. The theoretical analysis was to obtain Young's modulus, Poisson's ratio, and longitudinal velocity at different temperatures. The experiments validated the predicted results of ultrasonic change due to temperature increase and showed a maximum error of 3%. The experimental data of velocity and decibel change from the temperature range provide a reference for the future when dealing with unknown materials information on site that require a quick corrosion status determination.

Cellular automata (CA) models have emerged as a valuable tool in corrosion management. This manuscript provides an overview of the application of cellular automata models in corrosion research, highlighting their benefits and contributions to understanding the complex nature of corrosion processes. Cellular automata models offer a computational approach to simulate corrosion behavior at the microscale, capturing the intricate interactions between electrochemical reactions, material properties, and environmental factors generating a new vision of predictive maintenance. It discusses the key features of cellular automata, such as the grid-based representation of the material surface, the definition of state variables, and the rules governing cell-state transitions. The ability to model local interactions and emergent global behavior makes cellular automata particularly suitable for simulating corrosion processes. Finally, cellular automata models offer a powerful and versatile approach to studying corrosion processes, expanding models that can continue to enhance our understanding of corrosion and contribute to the development of effective corrosion prevention and control strategies.

The study reported the analytical approach on nine coins found in the wreck A of Fontanamare for understanding the complex corrosion processes that take place in underwater conditions. Optical microscopy (OM), combined with micro-Raman (µ-Raman) spectroscopy, and X-ray diffractometry (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM + EDS) were used to analyse the nature and the microstructure of the corrosion patina in comparison with the non-degraded state of coins. Three main type of corrosion patina based on copper, lead chloride and carbonate were identified: white-green, black and the obtained results for understanding the complex corrosion processes that take place in underwater conditions.

This paper investigates the effect of shot peening on the strength and corrosion properties of EN AW 6082-T651 aluminium alloy. Surface roughness, microhardness, residual stresses and corrosion performance were investigated and compared with the untreated aluminium alloy. Cracks and delaminations in the surface layer can only be seen on the treated specimens at a working pressure of 4 bar and 8 bar, while no such effect was observed at a working pressure of 1.6 bar. The effect of dislocation densification was confirmed by the microhardness measurement of the hardened layer, where microhardness increased by up to 23 % compared to the untreated aluminium alloy. Shot peening also results in a deeper layer with higher compressive residual stresses compared to untreated specimens. With higher working pressure, surface roughness increases, which can promote localized pitting corrosion. However, all treated specimens improve the corrosion resistance and have a lower degree of anodic dissolution. The current density of the shot peened specimen with the lowest surface roughness was more than twice lower than that of the untreated specimen.

This paper presents a new method of preparing a coating on the Ti65 titanium alloy by a two-step procedure comprising hot-dipped aluminum and solid carburization. The effects of the carburization in the presence of NaCl deposit at 810oC have been systematically studied. In this article, the microstructure, morphology, phase composition of the coating, and the corrosion products were investigated by SEM, EDS, and X-ray diffraction. Results indicated that the corrosion resistance of hot dip aluminum/carburizing composite coating was not significantly enhanced by hot dip aluminum coating. This can be attributed to the formation of TiC and Ti3AlC after carburization, which promoted the formation of loose and unprotected TiO2 in the coating during molten salt corrosion. In addition, the oxidation of the carbon atom into CO2 /CO leaded to a high concentration of vacancy in the coating, creating channels for NaCl to penetrate the coating and accelerated the corrosion rate.

The materials used as corrosion inhibitors are [Zn-Al-Cl], [Mg-Al-Cl], [Ni-Fe-Cl], and [Co-Fe-Cl] layered double hydroxides (LDHs). They were synthesized by coprecipitation and characterized by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and thermal anal-yses. The efficiency of these corrosion inhibitors on mild steel in concentrated hydrochloric acid (18.5%) at 60°C (chemical pickling conditions of steel) was studied using electrochemical and gravimetric methods for different concentrations. The surface morphology and composition were examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The inhibitory efficiency in the case of 1.2 g.L-1 LDH was found to be 83.33%, 83.65%, 68.38%, and 74.73% for [Ni- Fe-Cl], [Zn-Al-Cl], [Co-Fe-Cl], and [Mg-Al-Cl], respectively.

This work aims to follow the corrosion behavior of copper in 3 wt% NaCl solution in the presence of a bio-oily extract. Spent coffee grounds (SCG), a highly recyclable and usable biomass - often thrown away and becoming a serious threat to the environment - , has a fraction of oils (12%) that we have opted to use as a corrosion inhibitor for copper. The extraction was carried out using n-hexane as the solvent for the decoction. The oily fraction was analyzed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Potentiodynamic polarization measurements have revealed SCG extract acts as a cathode-type inhibitor for copper in saline media, mainly preventing the diffusion of oxygen molecules toward the substrate. As the extract concentration increased, the inhibition efficiency has improved as well, reaching 95.78 % with 0.6 g/L of SCG extract. The obtained results by electrochemical impedance spectroscopy (EIS) are in accordance with the order of inhibitory efficiency obtained by potentiodynamic polarization. We have found that the SCG extract adsorption process on copper surface is spontaneous and complies with Langmuir isotherm.

In this work, nitrite intercalated CaAl-LDH was firstly prepared in this work. Scanning electronic microscopy (SEM) coupled with the energy dispersive spectrometer (EDS) was used to characterize the morphology and element composition of the synthesized powder. Fourier transform infrared spectroscopy (FTIR) was used to characterize the chemical composition and X-ray diffraction (XRD) was used to analyze the structure. The nitrite release curve and the chloride concentration change curve were obtained to study the anion-exchange reaction. The corrosion protection effect of the CaAl-LDH loaded with nitrites towards the carbon steel was evaluated in 0.02 M NaCl solution by electrochemical impedance spectroscopy (EIS). Then the powder was added in the epoxy coating with a percentage of 2% (vs. epoxy resin). The coating morphology and roughness was evaluated by SEM and laser microscopy, and the corrosion protection effect was investigated by EIS in an immersion period of 21 d. Local electrochemical impedance spectra (LEIS) was used to characterize the corrosion development process in micro-corrosion sites. The corrosion product of the scratched area after salt spray exposure was analyzed by EDS and Raman spectroscopy. The corrosion protection mechanism of the CaAl-LDH loaded with nitrites was proposed based on the above experimental results.

The growing demands of material longevity in marine environments necessitate the development of highly efficient, low-cost and durable corrosion protective coatings. Although magnesium alloys are widely used in the automotive and aerospace industries, severe corrosion issues still hinder their long-term service in naval architecture. In present work, an epoxy composite coating containing sericite nanosheets is prepared on the AZ31B Mg alloy by one-step electrophoretic deposition method to improve corrosion resistance. Due to the PEI modification, positively-charged sericite nanosheets can be highly orientated in an epoxy coating under the influence of an electric field. The sericite-incorporated epoxy coating prepared in the emulsion with 4 wt.% sericite exhibits the highest corrosion resistance in 3.5 wt.% NaCl solution, as manifested by electrochemical corrosion and long-term immersion tests. The highly-orientated sericite nanosheets in epoxy coating provide excellent barrier effect against corrosive media, thereby significantly improving the long-term anti-corrosion performance of the epoxy coating. This work provides new insight toward the design of lamellar filler/epoxy coatings with superior anticorrosion performance and shows promise in the corrosion protection of magnesium alloys.

Cathodic protection is widely used to protect metal structures from corrosion and is commonly applied on marine structures in seaports using sacrificial galvanic anodes. These anodes, either in Zinc, or preferen-tially nowadays in Al-Zn-In alloys, are expected to corrode instead of the metal to be protected. This leads to the release of specific dissolved species, Zn2+, Al3+, In3+ and solid phases like Al(OH)3. Few studies were conducted on the effects of anodes on marine organisms and concluded that further detailed investiga-tions are needed in controlled environments. We therefore propose an experimental approach to evaluate the effects of Zn and Al-Zn-In anodes on oysters stabulated in tanks, under conditions approaching those used in the ports. We chose a non-targeted metabolomic approach, using UHPLC coupled to HRMS, to study the effects on the entire metabolome, without any a priori. A modelling study of the chemical species, corresponding to the deg-radation products of the anodes, likely to be present near the exposed oysters, was also included. We identified 16 and 2 metabolites modulated by Zn- and Al-Zn-In-anodes respectively, involved in bi-ological functions, such as energy metabolism, osmoregulation, oxidative stress, lipid, nucleotide nucle-oside and amino acid metabolisms, defense and signaling pathways.

The method of micro-arc oxidation has been utilized to synthesize a protective biocompatible coating for a bioresorbable orthopedic Mg implant. This paper presents the results of a comprehensive research of micro-arc coatings based on diatomite – a biogenic material consisting of shells of diatom microalgae. The main focus of this study was the functionalization of diatomite-based micro-arc coatings by incorporating the particles of titania (TiO2) into them. Various properties of the resulting coatings were examined and evaluated. The XRD analysis has revealed the formation of a new magnesium orthosilicate phase – forsterite (Mg2SiO4). It has been established that the corrosion current density of the coatings has decreased by 2-4 orders of magnitude after the inclusion of TiO2 particles, depending on the coating process voltage. The adhesion strength of the coatings has increased following the particle incorporation. The processes of dissolution of both coated and uncoated samples in a sodium chloride solution were studied. The in vitro cell viability was assessed, which showed that the coatings significantly reduce the cytotoxicity of Mg samples.

Nitriding has long been used to engineer the surfaces of engineering steels to improve their surface and subsurface properties. The role of the surface compound layer (’-Fe4N and/or -Fe2-3N) in improving the tribological and corrosion resistant properties of nitrided steels has been established. However, there have been very few studies on the response of the compound layer to tribocorrosion in corrosive environments. In this work, the tribocorrosion behaviour of a 5 m thick ’-Fe4N nitride layer produced on mild steel (MS) by plasma nitriding has been studied in a NaCl containing solution under various electrochemical conditions. The results show that at a cathodic potential, where mechanical wear is predominant, the total material removal (TMR) from the ’-Fe4N layer is 37% smaller than that from the untreated MS, and at open circuit potential, TMR from the layer is 35% smaller than that from the untreated MS, while at an anodic potential, the ’-Fe4N layer can reduce TMR from mild steel by 87%. The beneficial effect of the ’-Fe4N nitride layer in improving the tribocorrosion behaviour of mild steel is derived from its high hardness and good corrosion resistance in the test solution and its ability to resist both mechanical wear and chemical wear.

Organic Coatings have potential applications in the prevention of metal corrosion in an aqueous solution. The protective effect of SEBS coated copper corrosion in NaCl 3% solution was investigated by using electrochemical methods. The main objective of this work is to find the optimal conditions of the protocol immersion to evaluate the effects of SEBS ratio and two-immersion time on the anticorrosive behaviour of copper in 3 wt % NaCl solution in order to determine the best conditions to produce a protective SEBS film on the copper surface. Response Surface Methodology (RSM) is used as an optimization method. The study’s findings show the combination of three environmental factors that minimize corrosion rate. The Box-Behnken Design (BBD) is working perfectly for the statistical significance of the model (ANOVA test). This analysis calculates the contribution value of each parameter in changing the value of the corrosion rate (CR) in not only individual but also synergistic cases. The optimized parameters were found to be a 2.17% of SEBS ratio, 20 min of immersion 1, and 21 min of immersion 2. The electrochemical impedance spectroscopy tests confirmed the results.

The present paper describes a study case of the failure investigation of Duplex stainless steel (UNS S31803) on the tube and tube sheet section of a shell and tube heat exchanger BEM TEMA type with seawater as the cooling medium. Although UNS S31803 offers high strength, high resistance to chloride-induced SCC, and high resistance to pitting attack in chloride environments, in this study case, the heat exchanger experienced some material degradation; 26 tubes were leaked and plugged on both sides, and scales plugged 76 tubes. The examination in this study case revealed the formation of biofilm inside the tubes, XRD examination revealed that the film contained aragonite (CaCO3), and by using microstructural examination on the inner surface of the tube, the austenite grains were preferentially attacked by crevice corrosion. In this case, the failure was caused by crevice corrosion, and crevice corrosion was enhanced by microbiological-induced corrosion (MIC). Recommendations to avoid similar failures are also suggested in this paper.

The paper investigates the influence of ion nitriding on the microstructure, corrosion resistance, and tensile strength at elevated temperatures of Haynes 282 nickel superalloy specimens produced by the Direct Metal Laser Sintering-DMLS technique. Analysis of the specimens’ surface morphology revealed that the ion nitriding process significantly affects the physical and chemical phenomena occurring on the surface of the specimens. Phase composition and stress analysis showed that Haynes 282 nickel alloy specimens produced by the DMLS technique and a chromium nitride layer produced in the ion nitriding process have tensile stress. The layer is also characterized by high nanohardness compared to specimens produced using the classical method (wrought) and DMLS technique. The conducted corrosion resistance tests confirmed the positive effect of the nitrided layer on the corrosion resistance of Haynes 282 nickel alloy produced by the DMLS technique. The ion nitriding process did not significantly affect the elevated-temperature tensile strength of Haynes 282 nickel alloy specimens produced by the DMLS technique.

This study investigates the stress corrosion cracking (SCC) behavior of type 316L stainless steel (SS316L) produced with sinter-based material extrusion additive manufacturing (AM). This technology has been shown to produce SS316L with microstructures and mechanical properties comparable to its wrought counterpart in the annealed condition. However, despite plenty of research on SCC of SS316L, little is known about SCC in sinter-based AM SS316L. This study focuses on the influence of sintered microstructures on susceptibility to SCC initiation and crack-branching. Custom-made C-rings were exposed to different stress levels in acidic chloride solutions at various temperatures. To better understand the SCC behavior of SS316L, solution-annealed (SA) and cold-drawn (CD) wrought SS316L were tested for comparison. Results showed that sinter-based AM SS316L was more susceptible to SCC initiation than SA wrought SS316L but more resistant than CD wrought SS316L. Moreover, sinter-based AM SS316L showed noticeably better resistance to crack-branching than both wrought SS316L counterparts. The investigation was supported by comprehensive pre- and post-test microanalysis using light optical microscopy (LOM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and micro-computed tomography (micro-CT)

In this study, we investigated the inhibiting effect of Dioscorea spp leaf extracts on the corrosion of mild steel in selected media using the weight loss method. The mild steel samples were pre-weighed and immersed in NaOH, NaCl and H₂SO₄ solutions respectively containing the leaf extracts, with the control samples immersed in solutions of the media containing no extract. The samples were allowed to stand for 672 hours, with a set of samples from each environment withdrawn at intervals of 168 hours for corrosion characterization. The results obtained from all the environments indicate that the corrosion rate increased as concentrations of Dioscorea spp increased. Results also confirmed that the extract was an effective and excellent inhibitor in the alkaline, salt, and acidic media. Conclusively it was proven that the higher concentration of Dioscorea spp leaf extracts in the media had the best inhibition characteristic on the mild steel in the selected environments. The results show good potential for application in manufacturing industries. The microstructure analysis of the various test coupons in the test media should be carried out to reveal the influence of adding the leaf extracts to the stimulated media on the grain structure distribution of the mild steel.

The organic coating of bridge steel girders is subjected to physical scratches, corrosion, and aging in natural weathering. The breakdown of the coating may cause serviceability and safety problems if left unnoticed. A hyperspectral imaging method is proposed to detect the condition of steel coatings based on coating-responsive features in reflectance spectra. A field test was conducted on the real-world bridge which shows obvious signs of degradation. The hyperspectral signature enables an assessment of the coating health and defect severity. The results indicated that the coating scratch can be effectively located in the domain of a hyperspectral image and the scratch depth can be determined by mapping a scratch depth indicator (SDI=R532nm / R641nm). Rust sources and products in steel girders can be identified by the unique spectral signatures and the rust stains (and thus stain areas) scattered on the coating can be pinpointed at pixel level by the corrosion rust indicators. The chemical integrity of a topcoat is demonstrated by the short-wave infrared spectroscopy and the topcoat degradation can be evaluated by the absorption at 8000 cm-1 and 5850 cm-1.

Al has very good corrosion resistance and corrosion properties. The corrosion resistance of Al cast alloys is different because these alloys contain a lot of elements. Especially in secondary alloys which contain more impurity elements from which Fe is the most common. This study deals with secondary AlSi7Mg0.3 cast alloys which contain more Fe and are affected by a chloride corrosion environment. This environment was selected based on the application of castings in the automo-tive industry. The main object was to research the effect of such an environment on basic me-chanical properties and fatigue properties. The results show that a higher Fe content does not lead to a significant reduction in the properties of the casting and the chloride environment is not so harmful. Therefore, can be stated that the investigated secondary sand-cast experimental materials can replace the primary alloys without losing the required corrosion and mechanical properties.

TiNi alloys are very widely used materials for implant fabrication. When applied as rib replacement, they are required to be manufactured as combined porous-monolithic structure, ideally with a thin porous part well-adhered to its monolithic substrate. Additionally, good biocompatibility, high corrosion resistance and mechanical durability are also highly demanded. So far, all these parameters were not achieved in one material, which is why active search in the field is still underway. In the present work, we prepared new porous-monolithic TiNi materials by sintering a TiNi powder (0-100 µm) on monolithic TiNi plates followed by surface modification with high-current pulsed electron beam. The obtained materials were evaluated by a set of surface and phase analysis methods, after which their corrosion resistance and biocompatibility (hemolysis, cytotoxicity, and cell viability) were evaluated. Finally, cell growth tests were conducted. In comparison with flat TiNi monolith, the newly-developed materials were found to have better corrosion resistance, also demonstrating good biocompatibility and potential for cell growth on their surface. Thus, the newly-developed porous-on-monolith TiNi materials with different surface porosity and morphology show promise as potential new-generation implants for rib endoprostheses.

Activated Corrosion Products (ACPs) formation and deposition pose a critical safety issue for nuclear fusion reactors. The working fluid transports the ACPs towards regions accessible to worker personnel. Predicting ACPs formation deposition and transport is fundamental for source term identification, reduction of radiation exposure assessment, maintenance plan definition, design optimization, and waste management. The code OSCAR-Fusion has been developed by the CEA (France) to evaluate the ACPs generation and transport in closed water-cooled loops for fusion application. This work aims at assessing the impact of water chemistry on the transport, precipitation, and deposition of corrosion products for the EU-DEMO divertor Plasma Facing Unit Primary Heat Transfer System. Sensitivity analyses and uncertainty quantification are needed due to the multi-physics phenomena involved in ACPs formation and transport. The OSCAR-Fusion/RAVEN code coupling developed by the Sapienza University of Rome and ENEA has been used. This work presents the perturbation results of different parameters chosen for a closed water-cooled loop considering a continuous scenario of 1888 days. The aim of this work is to assess the variation of build-up of ACPs, perturbing the alkalizing agent concentration into the coolant and the corrosion and release rates of different materials.

Molten LiCl-KCl salt and liquid cadmium are proposed as the electrolyte and the reactive cathode for the electrorefining of spent nuclear fuels. Corrosion testing of existing alloys is mandatory to ensure the service life of the electrorefiner vessel and electrode assemblies. Haynes C276, Inconel 600, AISI 316L stainless steel, and 42CrMo low alloy steel were exposed to LiCl-KCl melt at 500°C for 500 h in an argon atmosphere. All alloys suffered from dissolution attacks with the presence of oxide islands or porous oxide layer on the surface. AISI 316L, T91 steel and tungsten specimens were also submitted to corrosion tests in liquid cadmium at 500°C for 120 h. Corrosion of AISI 316L and T91 stainless steel were predominated by chemical oxidation with additional severe Ni dealloying occurred on AISI 316L. Tungsten only suffered from dissolution attack in comparison.

Near-neutral pH and low redox potentials (EH) are considered favorable conditions for radionuclides immobilization in deep repository systems in clay geological formations. Cigeo is a future Industrial Centre for Geological Disposal for Nuclear Waste (NW) for high-level and intermediate level long-lived radioactive waste, to be built in France, at 500 m depth within the Callovo-Oxfordian clay formation. Deep knowledge of the mechanisms and kinetics of corrosion occurring at the external surface of tubings made of API 5L X65 carbon steel (CS-X65) in contact with COx pore water, is essential for a reversible NW management of the Cigeo site. By using robust handmade electrodes and electrochemical and gravimetric techniques, this work aimed to determine the corrosion phenomenology and kinetics of CS-X65 in contact with COx pore water flowing continuously through a Multi-Parameter Probe (MPP) device, placed at 500 m depth, for more than 180 days. It also aimed at demonstrating the reliability and the robustness of the measurement methodology for the corrosion evaluation of the metallic liner of the future nuclear waste disposal site. Two iron oxidants were encountered, oxygen, who was depleted, and proton, who was accompanied by hydrogen sulfide. Corrosion mechanisms and kinetics were well established for two CS-X65, electrochemically perturbed and not. The corrosion thickness loss rates stand between 0.016 and 0.032 mm/y.

The present study concerns the application of electrochemical chloride extraction to concrete designed with partial replacements of Ordinary Portland Cement (OPC) from different binders, namely ground granulated blast furnace (GGBS), pulverized fly ash (PFA) and Silica Fume (SF), to attend the need of corrosion repair for modern constructions. Electrochemical Chloride Extraction (ECE) was applied to the specimens at a current density of 2A/m2 for 4 weeks. The chloride types and binding mechanisms appeared to have important implications on the different performance of treatment perceived for all binders. Considering total chlorides, removal was more significant for OPC and GGBS when compared to others. The main difference noted was that for GGBS the removal of bound chlorides was more significant due to a possible release of adsorbed chlorides from the silicate hydrates, present at higher intensities in this case. However, even though GGBS had greater rates of bound chloride removal it had still the same percentage as OPC for total efficiency due to the fact that in OPC the removal of free chlorides is more expressive.

The importance of understanding the corrosion mechanisms of excavated metal artefacts help in determining the physico-chemical parameters of the burial environment and the formation of different corrosion products. These products can be observed and analysed with the help of various techniques that provide information on their morphology, chemical composition and structure. The analysis of ancient coins is extremely challenging in the presence of heavily corroded surfaces; as quantitative information may not exactly concur with its bulk composition. In the case of silver coins, the use of surface information can be used as a guide for bulk composition only. The current study carries out investigation and characterization of selected coins from a large coin hoard excavated from Amheida, Dakhla oasis, Egypt. The study and analysis of the alloy composition and corrosion products was performed using a multi-technique approach which included Light optical microscopes, Scanning Electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) and X-ray diffraction analysis. Investigation of the coins revealed the presence of a thick active inhomogeneous corrosion crust, while analysis showed that the coins were made from a binary silver copper alloy (billon) while the corrosion crust was rich in chlorides and carbonates, later identified by XRD analysis as Paratacamite, Malachite and Chrysocolla.

A diffusion welding of coarse-grained and ultrafine-grained (UFG) specimens of titanium near-α alloy Ti-5Al-2V used in nuclear power engineering was made by Spark Plasma Sintering. The failure of the welded specimens in the conditions of hot salt corrosion and of electrochemical corrosion were shown to have preferentially intercrystalline character. In the case of presence of macrodefects, crevice corrosion of the welded joints was observed. The resistance of the alloys against the intercrystalline corrosion was found to be determined by the concentration of vanadium at the titanium grain boundaries, by the size and volume fraction of the β-phase particles and by the presence of micro- and macropores in the welded joints. The specimens of the welded joints of the UFG alloy have higher hardness, hot salt corrosion resistance and the electrochemical corrosion.

To provide carbon steel a long corrosion protection effect in NaCl solution with various pH, a pH-controlled intelligent inhibitor based on poly-acrylamide (PAM) and oleate imidazoline (OIM) was synthesized. SEM, FT-IR and TGA results indicating the OIM inhibitor was successfully loaded into PAM hydrogel with a very high content (39.64 wt%). The OIM release behavior from hydrogel structure have two stages, quickly release and sustained release. The pH of solution could affect the initial release kinetics of OIM inhibitor and the diffusion path in hydrogel structure. Weight loss measurement of L80 steel in different pH solution with OIM@PAM proved the inhibitor responsive release mechanism and an-ti-corrosion performance. The inhibition efficiency of OIM@PAM can maintain over 80% after long term immersion in harsh corrosive environment (pH 3), which is much higher than the inhibition efficiency of inhibitor in moderate corrosive solution.

In order to produce nanostructured Ti0.9Cr0.1C powders, an elemental powder mixture of titanium, chromium, and graphite is milled in this work using a high-energy ball mill for various milling times. Microstructural characteristics such as crystallite size, microstrain, lattice parameter, and dislocation density are determined using X-ray diffraction (XRD). Mechanical alloying successfully produced nanocrystalline (Ti,Cr)C with an average crystallite size of 11 nm. This size of the crystallites is also directly verified using transmission electron microscopy (TEM). Scanning electron microscopy (SEM) was used to investigate the morphology of the samples. The novelty of this work is advancing the scientific understanding of the effect of milling time on the particle size distribution and crystalline structure, and also understanding the effect of the spark plasma sintering on the different properties of the bulks. Densified cermet samples were produced from the nanocrystalline powders, milled for 5, 10 and 20 hours by SPS process at 1800 degrees for 5 min under a pressure of 80 MPa. Phase changes of the produced cermets were examined according to XRD, SEM/EDX analyses. Significant amounts of Cr and Fe elements were detected, especially in the 20 h milled cermet. The bulk forms of the milled powders for 5 and 20 h had a relative density of 98.43 and 98.51 %, respectively. However, 5 h milled cermet had 93.3 HRA because of the more homogeneous distribution of the (Ti,Cr)C phase, the low iron content and high relative density. According to the 0.0011 mm/year corrosion rate, and 371.68 kΩ*cm2 charge transfer resistance obtained from the potentiodynamic polarization and EIS tests, the 20 h cermet was the specimen with the highest corrosion resistance.

One of the influential factors in estimating the service life of reinforced concrete bridges (RCB) is determining the long-term seismic performance of these structures. Corrosion due to chloride ion diffusion leads to the destruction of critical members of the RCB during the useful life of the structure. So, the long-term seismic performance of the bridge deteriorates as a result. It is essential to study the effect of corrosion deterioration on the long-term seismic performance of bridges in the southern regions of Iran, near the coasts of the Persian Gulf and the Oman Sea, because of the seismicity of the region and high corrosion rate of reinforced concrete (RC) members is the result of environmental conditions. In order to investigate this issue, considering studies about environmental conditions of southern Iran, the onset time of corrosion in the columns, as seismic critical members of the bridge, was determined. Based on that, the corrosion's effect on characteristics of RC at specific time points during the bridge's useful life (0, 15, 30, 45, 60, 75 and 90 years) have been calculated. The effects of corrosion include deterioration of the core and cover concrete properties, steel bar and the connection between concrete and steel bar. In the next step, at each time point, according to the modified stress-strain relationships, the moment-curvature analysis of the bridge pier was done, and the properties of the plastic hinge were determined. Finally, based on the obtained data about plastic hinge characteristics at each time point, overload analysis of the bridge was performed in both longitudinal and transverse directions. Then the capacity curves of RCB were compared at the mentioned time-points. The results show that the capacity of the bridge deteriorates over time due to corrosion. Therefore, a proposal to increase the value of base shear design has been made to ensure the long-term seismic performance of RCB in corrosive environments.

Nanopeening treatment was applied to the AISI 420 steel to decrease its sensitivity to the tribocorrosion damage. Microstructural investigation highlighted that the Nanopeening treatment led to a high plastic deformation and nanostructured surface layer with 110 µm depth. . In order to study the combined effect of corrosion and mechanical wear, tribocorrosion tests were performed on non–treated and nanopeened samples in boric acid and lithium hydroxide solution, considering both continuous and intermittent sliding. It was found that the AISI 420 steel is sensitive the synergism between mechanical friction and electrochemical corrosion with a domination of abrasive wear. Adhesive wear was also detected in the wear track. Indeed, the mechanical wear was pronounced under intermittent sliding because of hard wear debris generation from the repassivated layer during rotating time. The Nanopeening treatment led to enhance mechanical performance and corrosion properties. Such improvement could be explained by the high plastic deformation resulting in the nano-structuration of grains and increasing hardness of AISI 420 steel.

Atmospheric corrosion of aluminum aircraft structures occurs due to numerous reasons. A typical phenomenon leading to corrosion is the deliquescence of contaminants such as salts due to changes in relative humidity (RH) caused by aircraft operation at different altitudes and climate zones. Currently, corrosion of aircrafts is controlled by scheduled inspections. In contrast, the present contribution aims for a continuous monitoring approach by using the acoustic emission (AE) method to detect and further evaluate atmospheric corrosion. The AE method is frequently used for corrosion detection at typically immersion-like conditions or for corrosion types where stress-induced cracking is involved. However, it has not yet been demonstrated for atmospheric corrosion at unloaded aluminum structures. To address this question, the present investigation uses small droplets of a corrosive sodium chloride (NaCl) solution to induce atmospheric corrosion on aluminum alloy AA2024-T351. Operating conditions of an aircraft are simulated by a controlled variation in RH. In addition, videos of the corrosion site are recorded to visually observe the corrosion process. Pitting corrosion is generated and clearly measurable AE signals are detected. An automatic video processing algorithm looking for sudden changes on the corrosion site mainly detects hydrogen bubbles formed when aluminum reacts with aqueous solutions. A clear correlation between the observed pitting corrosion, the AE and the hydrogen bubble activity and the RH, i.e., the electrolyte present at the aluminum surface, is found. Thus, the findings demonstrate the applicability of the AE method for monitoring atmospheric corrosion of aluminum aircraft structures by today’s measurement equipment. Numerous potential effects that can cause measurable AE signals are investigated and discussed. Among these, bubble activity is clearly considered to be the most emissive one.

Zinc protection of galvanized steel is initially dissolved in alkaline solutions. However, passive layer is formed over time which protects the steel from corrosion. The behavior of galvanized steel exposed to strong alkaline solutions (pH values of 12.7) with a fixed concentration of sulfate ion of 0.04M is studied. Electrochemical measurement techniques such as corrosion potential, linear polarization resistance and electrochemical impedance spectroscopy are used. Synergistic effect of sulfate ion is also studied together with other anions such as chloride Cl- or bicarbonate ion HCO3- and with other cations such as calcium Ca2+, ammonium NH4+ and magnesium Mg2+. Presence of sulfate ions can depassivate the steel, leading to corrosion density of 0.3 µA/cm2 at the end of the test. The presence of other ions in the solution increases this effect. The increase in corrosion density caused by cations and anions responds to the following order (greater to lesser influence): NH4+>Ca2+>Mg2+ and HCO3- >Cl- >SO42-.

The corrosion behavior of Fe-containing directionally solidified (DS) and centrifugally cast (CC) Al-Si-Cu-Zn alloys with either Co or Ni additions has been investigated. Electrochemical and immersion corrosion methods were used to investigate the corrosion behavior in 0.6 M NaCl after short (1-hour) and long (30-day) exposure periods. The employed solidification methods allowed the production of samples with a wide range of secondary dendrite arm spacing (SDAS) while preserving Si and Fe-containing phases. The 0.5 wt.% Ni and Co additions led to the growth of the AlFeSi(Ni) and AlFeSi(Co) phases, but no binary AlNi nor AlCo intermetallic par-ticles have been generated. Potentiodynamic polarization studies at early exposure revealed an increase in the corrosion potential as the Ni was added for either fast or slow solidified samples. The electrochemical impedance spectroscopy at early exposure demonstrated that the Ni-modified alloy, on the other hand, was associated to smaller charge transfer resistances, in-dicating a reduction in corrosion resistance after short elapsed time into the electrolyte. Howev-er, 30-day immersion tests revealed much lower corrosion rate of the Ni-modified alloy than the other alloys, while the corrosion rates of the Co-modified and non-modified alloys were simi-lar. In the Ni-containing alloy, decreased corrosion rate under long-term corrosion process was attributed to the formation of a thick and dense alumina layer, effectively protecting the surface under such conditions. This work contributes to a better knowledge of the corrosion behavior of Ni- and Co-corrected Al industrial scrap compositions.

The three-phase separator was perforated after four years’ service. The perforation position is at the bottom of the vessel under the baffle plate in an oil transfer station. The cause of perforation was investigated by chemical analysis using a direct-reading spectrometer, microstructure examined by optical microscope(OM), and lab simulated corrosion experiments by electrochemical workstation, and the corrosion products examined with scanning electron microscopy(SEM), energy dispersive spectrometer(EDS) in this paper. The analyses indicated that the coating at the base of the pressure vessel failed and this led to the direct exposure of the carbon steel plate to the corrosive medium. The electrical contact between the carbon steel and the stainless steel, sets up a galvanic cell that accelerated the corrosion of the pressure vessel which eventually led leads to the perforation.

In the present study, the corrosion resistance of amorphous coating and composite coatings in 3.5 wt.% NaCl, 0.5 M H₂SO₄ and 10 wt.% NaOH solution were studied. The composite coatings exhibit superior corrosion resistance. When the content of AT13 （Al₂O₃–13 wt.% TiO₂）was 15 wt.%, the composite coating has the lowest corrosion current density (1.75×10^-6 A cm^-2), which is 5.14×10^-5 A cm^-2 for Fe-based metallic glassy coating, and the highest corrosion potential (-411 mV), which is -580 mV for Fe-based metallic glassy coating. The breakdown potential of the passivation film in 3.5 wt.% NaCl solution was much higher than that of 316L.The long-time immersion corrosion tests carried out on different coatings showed that the corrosion protection effect of coating was enhanced with the increase of the amount of AT13 added.

Speleothems have proven to be one of the most reliable terrestrial archives for palaeoclimate research. However, due to the complexity of karst systems, long-term monitoring and high-resolution analyses of the cave atmosphere and water geochemistry have become essential to better constrain the factors that control calcite growth and how geochemical palaeoclimate proxies are encoded into speleothems. While calcite precipitation incorporates the palaeoclimate signals into the speleothem fabric, certain conditions in caves can favour dissolution, which may form hiatuses or even destroy these signals. In extreme cases, in-cave dissolution by dripwater can form cup-shaped features (i.e., corrosion cups), which were the main focus of this study. The study site in Postojna Cave, Slovenia, was investigated through cave climate monitoring and drip and cup water sampling, which took place during 2017–2021. We found that the cups are fed by low calcium drips as the consequence of the thin vadose zone above the cave. Due to the specific configuration of airflow pathways, the study site accumulates high levels of CO2 (>10,000 ppm), which shifts low calcium dripwater into undersaturation. This causes dissolution on rock surfaces and speleothems on the cave floor. The results of this study have broader significance in addressing the suitability of cave environments and speleothems used in paleoclimate research.

For better understanding the corrosion and corrosion products behavior in the primary circuit of lead-bismuth eutectic (LBE) coolant reactor, the concentration distribution of soluble impurities and the transport of solid particles are investigated through finite-element method. An axisymmetric model of the primary circuit of LBE reactor was constructed to accelerate the calculation the thermal hydraulic filed of circuit. The saturation concentration of solute Fe, Cr and Ni in LBE coolant are identified through the equilibrium of their oxides and PbO. And the very different saturation concentrations of Fe/Cr/Ni in LBE will lead to significant element selective corrosion. The migration of solid oxides particles in the primary circuit is also investigated by the Euler-Lagrange tracing model. The simulation shows that driving force for the movement of particles >100 μm is buoyancy, which lets particles float on a free surface, while particles <10 μm tend to suspend in coolant. However, the behavior of particles also depends on the formation position, the particles formed above the core have the high possibility of re-entering in the core.

The outdoor sculpture of the first Portuguese king, D. Afonso Henriques (~1109 – 1185 AD), placed in Guimarães (North Portugal) is one of the most emblematic national sculptures. Created in 1887 by António Soares dos Reis, it possesses a remarkable symbolic value in the presumed birthplace of the king. In addition to the artistic and heritage importance of the monument, it is one of the few sculptures cast by a Portuguese industrial foundry in the 19th-century. This study obtained data on the sculpture's elemental composition and corrosion products, gathering important historical and technical information. For this purpose, a multi-analytical approach consisting of X-ray fluorescence (XRF), X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM-EDS) was carried out to characterise the bulk metal and corrosion layers. The data revealed a ternary alloy of Cu, Sn, Zn with Pb, Fe, As, Bi and Mn as minor elements. The alloy matches that of other sculptures cast in that period. In terms of corrosion, it is characterised by the presence of oxides. These results represent the first step for applying an appropriate conservation strategy for bronze sculptures with similar characteristics.

The altered nature of archaeological metals means they deteriorate at conditions where metals would be stable. The study of deterioration for such materials is hampered by their complexity, variability and difficulties in measuring deterioration. Placing an object in a sealed container, controlling the RH and pollutant gases and measuring any decrease in oxygen concentration is an accessible method to measure deterioration rate. It has been used for research into suitable environmental conditions to manage deterioration rates of such artefacts including differences in response for artefacts from different excavation sites. Some objects need careful control of RH to low values, this is expensive to maintain and poses risks to other artefacts displayed together. Many objects are actually stable up to quite high RH values and oxygen depletion testing has been used to identify those that can be safely displayed with minimal environmental control. The accelerated corrosion, ‘Oddy’ test is frequently used to sift out unsuitable display materials. The visual assessment is widely recognized to be subjective. The test container has been modified and oxygen depletion appears to give good quantitative measurements of corrosion that correspond with both visual comparison and corrosion quantification for copper, lead and steel, but not for silver.

Our investigations show that electrochemical corrosion of copper is faster than electrochemical corrosion of aluminium at temperatures below 100oC. Literature data analysis shows that the Al atoms diffuse faster than the Cu atoms at temperatures higher than 475oC, Al rich intermetallic compounds (IMCs) are formed faster in the Cu-Al system, and the Kirkendall plane shifts toward Al side. Electrochemical corrosion occurs due to electric current and due to diffusion. An electronic devise working time, for example, depends on initial copper cover thickness on aluminium wire, connected to the electronic devise, temperature, and volume and dislocation pipe diffusion coefficients, so copper, iron, and aluminium electrochemical corrosion rates are investigated experimentally at room temperature and at temperature 100oC. Intrinsic diffusivities ratios of copper and aluminium at different temperatures and diffusion activation energies in the Cu-Al system are calculated by proposed here methods using literature experimental data. Dislocation pipe and volume diffusion activation energies of pure iron are calculated separately by earlier proposed method using literature experimental data. Aluminium dissolved into NaCl solution as the Al3+ ions at room temperature and at temperature 100oC, iron dissolved into NaCl solution as the Fe2+ (not Fe3+) ions at room temperature and at temperature 100oC, copper dissolved into NaCl solution as the Cu+ ions at room temperature and as the Cu+ and the Cu2+ ions at temperature 100oC. It is founded experimentally that copper corrosion is higher than aluminium corrosion, and ratio of electrochemical corrosion rates, kCu/kAl>1, decreases with temperature increasing, although iron electrochemical corrosion rate doesn’t depend on temperature below 100oC. It is obvious, because melting point of iron is more higher then melting point of copper or aluminium. It is calculated that copper electrochemical corrosion rate is approximately equal to aluminium electrochemical corrosion at temperature about 300oC, so copper can dissolve into NaCl solution mostly as the Cu2+ ions at temperature about 300oC. Ratio of intrinsic diffusivities, DCu/DAl <1, increases with temperature increasing, and intrinsic diffusivity of aluminium could be approximately equal to intrinsic diffusivity of copper at temperature about 460oC.

In this study, grit blasting pretreatment was used to improve the adhesion and corrosion resistance and microhardness of Ni-W/SiC nanocomposite coatings fabricated using conventional electrodeposition technique. Prior to deposition, grit blasting and polishing (more commonly used) pretreatment were used to prepare the surface of the substrate and the 3D morphology of the pretreated substrates was characterized using laser scanning confocal microscopy. The coatings surface and the cross section morphology were analyzed using scanning electron microscopy (SEM). The chemical composition, crystalline structure, microhardness, adhesion, and the corrosion behavior of the deposited coatings were characterized using energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), microhardness tester, scratch tester and electrochemical workstation, respectively. The results indicated that the grit blasting and SiC addition, improved the microhardness, adhesion and corrosion resistance. The Ni-W-SiC nanocomposites pretreated by grit blasting exhibited the best adhesion strength, up to 36.5 ± 0.75 N. Its hardness was the highest and increased up to 673 ± 5.47Hv and its corrosion resistance was the highest compared to the one pretreated by polishing.

The corrosion morphology in grade 2205 duplex stainless steel wire has been studied to understand the nature of pitting and the causes of the ferrite phase's selective corrosion in acidic NaCl solution. It is shown that the corrosion mechanism is always pitting, which either manifests lacy cover perforation or densely-arrayed selective cavities developing on the ferrite phase. Pits with a lacy metal cover form in concentrated chloride solutions, whereas the ferrite phase's selective corrosion develops in diluted electrolytes, showing dependency on the chloride-ion concentration. The pit perforation is probabilistic and occurs on both austenite and ferrite grains. The lacy metal covers collapse in concentrated solutions but remain intact in diluted electrolytes. The collapse of the lacy metal cover happens due to hydrogen embrittlement. Pit evolution is deterministic and occurs selectively in the ferrite phase in light chloride solutions.

The control of air quality in museums or storages is of fundamental interest for the conservation of historic artifacts. The present work reports an example of application of RFID sensors developed in the European project SensMat and dedicated to this issue. The sensors are based on the varia-tion of property of an RFID tag coupled to a sensitive silver thin film exposed to the environment. As it will be described in the paper, such low cost sensors are interrogated by a commercial reader and provide the environmental corrosivity index and thus the presence of pollutants. The selected case study concerns the monitoring of pollution by H2S in a building dedicated to conservation and restoration of archeological and historical woods. The ability of sensors to map spatially the corrosivity within buildings is highlighted.

In this paper, a novel biocompatible alloy defined as FeMoTaTiZr was obtained and functionalized by hydroxyapatite-based coatings (HAP) in order to increase their biocompatibility, bioactivity, and resistance to corrosion for to be used as bone implants. To obtain the surface with antibacterial properties, the HAP coatings were doped with small amount of Zn. The alloy was prepared using the VAR (Vacuum Arc Remelting) equipment, while the coatings by RF magnetron sputtering method. The EDS analysis confirmed the presence of Ca and P in the case of all developed coatings, having Ca/P or Ca/(P+Zn) ratio of about 1.70 and 1.66, respectively. The XRD and ATR-FTIR investigations confirmed the presence of calcium phosphate phases. The roughness of uncoated substrates increased after coating with HAP, and it was considerably increased by the Zn addition. The electrochemical tests showed that the un-doped HAP exhibited good corrosion behavior, while Zn doped HAP coatings have a high dissolution rate in fetal bovine serum, being more proper as a biodegradable material.

Worldwide, millions of kilometres of sewers are constructed from concrete pipes. Unfortunately, concrete sewers are susceptible to corrosion from biogenic hydrogen sulphide, and though they may pass visual inspection, their ability to hold together under load may be degraded. This paper presents the design of a teleoperated robot with a protractible probe, that allows an operator to apply a localised load to selected points within a concrete sewer pipe. We report findings from laboratory and field trials of our prototype, with initial results suggesting that this approach has the potential to contribute useful information to sewer maintenance planning.