Effect of Cr₂O₃ microparticle on microstructure and tribological behavior of microarc oxidation coating on Ti6Al4V alloy

Microarc oxidation (MAO) coating on Ti6Al4V alloy was treated in the electrolyte adding Cr₂O₃ microparticle. The influence of Cr₂O₃ particles on morphology, phase constituent and tribological behavior of MAO coatings was analyzed by SEM, XRD and wear test. The results show that the surface micropore of the composite coating decreases, the wear resistance improves, and the surface of composite coating appears Cr₂O₃ phase when Cr₂O₃ microparticles are added to MAO electrolyte. Besides, with increasing of Cr₂O₃ microparticle content in electrolytes, the thickness of the coating increases, and the X-ray diffraction peak of Cr₂O₃ phase enhances continuously, TiO₂ phase decreases gradually, and then Al₂TiO₅ phase tends to disappear. The friction coefficient of the composite coating reduces gradually when Cr₂O₃ particle content increases from 0.5 g/L to 1.5 g/L. The composite coating exhibits good wear resistance when the content of Cr₂O₃ microparticle in electrolyte is 1.5 g/L.