Anti-Wear Ceramic Coating Prepared On The Surface Of TC4 Titanium Alloy

In this paper, in order to improve reliability and repetitive-use properties of titanium fastening piece, microplasma oxidation method had been advanced on the surface technology. Anti-wear coatings were formed on Ti-6Al-4V substrate by microplasma oxidation. The effect of factors (electrolyte system, processing parameters and additive) on the structure and tribological properties of coatings were studied. The foundation for the application of microplasma oxidation on titanium fastening piece had been built.X-ray diffraction(XRD) and electronic differential system(EDS) were applied for detection of the phase and elemental composition of ceramic coatings. Scanning electron microscopy(SEM) and atomic force microscope (AFM) were employed for observation of the surface morphologies. Ectric eddy current thickness tester and digimatic hardness tester had been used to caculate the thicknesses and hardness of coatings, respectively. The sliding friction under low load and the anti-wear properties of coatings had been investigated by ball-on-disk and reciprocating friction and wear tester.The results show that coatings formed in aluminate solution has excellent property of anti-wearing. Structure, composition, surface hardness and friction coefficient of coatings can be adjusted by changing processing parameters. The range of surface hardness and friction coefficient under low load are about 150～640HV and 0.07～0.40 respectively. And the maximum life of cycle using can reach 128. Additive can improve structure and properties of coatings, small quantity of Na₂B₄O₇ was added in aluminate solution made coatings more crystallinity, compacter, harder and more uniform, which result in that friction coefficient under low load was decreased 64% and the life of cycle using under heavy load was increased to 840.Therefore, the microplasma coatings formed on surface of TC4 titanium alloy can improve the tribological behavior by the adjustment of electrolyte solution and altering processing parameters. Friction coefficient was decreased and the life of cycle using was extended enormously.