Micro-arc oxidation (MAO) ceramic coatings were prepared on TC4 titanium alloys by adding CuSO₄ to a (NaPO₃)₆ base solution. The microstructures of the MAO coatings were characterized by scanning electron microscopy (SEM), energy dispersive (EDS), and X-ray photoelectron spectroscopy (XPS). The corrosion resistance and wear resistance of these coatings were evaluated via hydrochloric acid immersion of weight deficit and friction tests. Those results indicated the presence of Cu in the MAO coating in the form of CuO and Cu₂O. Incorporation of CuSO₄ results in a thickness and roughness increase in the coating. The coating has a lower coefficient of friction (0.2) upon the addition of 4 g/L of CuSO₄. The antibacterial properties of the MAO coatings were maximized at 6 g/L of CuSO₄. However, the corrosion resistance of the copper-doped MAO coating did not exceed the undoped coating. This study shows that the addition of CuSO₄ to the electrolyte successfully prepared copper-containing micro-arc oxidation coatings, which improved the wear resistance and antibacterial properties of the coating.

By contrast with the traditional method of adding hard particles into micro arc oxidation (MAO) coating to improve its wear performance, this study introduced copper into the MAO coating on TC4 alloy by adding copper pyrophosphate to enhance the wear property in a marine environment and the antibacterial property. The results demonstrated that the MAO coating with copper pyrophosphate addition showed a porous structure, and Cu was mainly concentrated around micropores. CuO and Cu₂O were formed in this MAO coating. This MAO coating with Cu had a high bonding strength to the substrate. Although the hardness of the coating with Cu had been reduced, it could reduce the friction coefficient and enhance the wear property in simulated seawater due to the lubrication of Cu. Furthermore, this MAO coating with Cu addition had obvious antibacterial and bactericidal effects due to the antibacterial effect of Cu.

β-titanium alloys attract great interest in surgical implants due to its low elastic modulus. The addition of Ag further enhances the strength, ductility, corrosion resistance and biocompatibility of such alloys, which optimizes their compatibility with human bones. In this study, Ti-15Mo-xAg (x = 1, 5 wt.%) alloy rods were prepared by optimized melting, forging and rolling processes. The microstructural evolution, mechanical properties, corrosion behavior and biocompatibility of the alloy were systematically studied by X-ray diffraction (XRD), optical microscopy (OM), transmission electron microscopy (TEM), mechanical testing, electrochemical analysis and biocompatibility assays. The results showed that the aged Ti-15Mo-5Ag alloy presented a special heterogeneous microstructure of β matrix and micro-nano scale precipitated phase (α₁ + α₂ + Ti₂Ag), which enabled it to achieve excellent mechanical adaptability. Its tensile strength reached 1208 MPa, and the elongation was 11.5%, while the alloy maintained a low elastic modulus of 98 GPa. The self-corrosion current density of the alloy in the simulated body fluids was as low as 1.176 × 10^-8A·cm^-2. In vitro biological tests indicated good biocompatibility. This alloy is expected to become a candidate material for future surgical implant applications.