To enhance the service performance of titanium alloys for demanding high-end equipment applications, an h-BN/SiC-Ti-MAO composite coating was fabricated on Ti6Al4V via one-step micro-arc oxidation (MAO). Optimizing the SiC additive concentration offers an effective way to improve the overall performance of the composite coating in mechanical, tribological, oxidation resistance, and anti-corrosion properties. The research results show that the coating prepared with 4 g/L SiC yielded superior multifunctional properties. It possessed a dense microstructure with the lowest porosity (6.45%), high hardness (712 HV), and excellent adhesion. This coating maintained a low friction coefficient of approximately 0.20 from RT to 500°C and exhibited the best oxidation resistance at 600°C, with a parabolic rate constant (K P ) of 3.33×10 -4 . Electrochemical tests in 3.5 wt.% NaCl solution further confirmed its optimal anti-corrosion, showing the lowest corrosion current density (3.325×10 -9 A/cm 2 ). In contrast, insufficient SiC concentration results in limited performance improvement of the composite coating, whereas excessive concentration introduces microstructural defects, ultimately degrading the overall performance. This study demonstrates that optimized h-BN/SiC co-doping represents an effective strategy for developing high-performance MAO protective coatings on titanium alloys.
Wang et al. (Fri,) studied this question.