Sandblasting materials used for dental restoration is a valuable preconditioning technique enhancing the physical properties and promotes osseointegration and cell adhesion. Ti medical grade 4 and Ti6Al4V were blasted with a series of various naturally occurring and synthetically produced spraying materials of controlled granulometry, at precise spraying duration and spraying pressure, and the results were analyzed in terms of the obtained surface roughness and by SEM analysis. It was found that in all cases, regardless of the spraying material or working conditions, the roughness profile achieved is a uniformly distributed one. A reduction in the blasting pressure by half led to a decrease in the roughness between 30 and 35%. The use of glass balls as blasting material led to decreased roughness and a more uniformly distributed roughness values for Ti as well as for Ti6Al4V regardless of spraying duration or applied pressure comparing to other spraying materials, and blasting with olivine led to increased, as well as uniformly distributed values, and hence the conclusion that one may control the roughness size by choosing one or another from the above materials, without the need of changing any other operating parameters. In the case of Ti, the achieved roughness is greater than in the case of Ti4Al6V, irrelevant of the blasting material, the differences being smaller the softer the sandblasting material due to the fact that Ti alloys have better mechanical properties and increased hardness comparing to pure Ti. SEM analysis showed that the use of sintered hydroxyapatite as an additive to the blasting material does not necessarily lead to a substantial deposition of hydroxyapatite on the substrate materials, only traces of it being identified during the analysis.

Steel surface protection with hard coatings is essential in the metalworking industry, yet developing high-performance hard coatings still remains a challenge. Quaternary nitride coatings, particularly TiAlSiN, have been extensively studied, but commercial TiAlSiN coatings vary widely, and there is a lack of consistent data. This study presents findings on the development and evaluation of TiAlSiN and TiAlSiN/TiN thin films, with an 800 nm thick TiAlSiN top coating and a 100 nm thick TiN mid-coating. The films were deposited on C120 tool steel discs via reactive DC magnetron sputtering. Ti and TiAlSi 75–20–5 (at.%) disc-shaped targets (50.8 mm diameter × 6.3 mm thickness), fabricated by our team through spark plasma sintering, were used for the sputtering process. Coatings were grown on smooth steel substrates heated to 300 °C, resulting in a uniform micro-structure with nanoparticles of globular (TiN) or pyramidal shape (TiAlSiN), as evidenced by SEM analysis. Nanoindentation tests showed superior mechanical properties for all coatings compared to the steel substrate. Micro-scratch tests indicated better scratch resistance for TiAlSiN/TiN bilayer (BL) coatings than for TiAlSiN single-layer (SL) coatings. Electrochemical impedance spectroscopy tests in a 3.5 wt.% NaCl solution revealed that the BL coatings demonstrated superior corrosion resistance compared to the SL coatings, even after thermal aging at 800 °C for 1 hour. The superior properties of the synthesized TiAlSiN/TiN films recommend them as protective coatings for tool steel surfaces.