Corrosion and wear properties of h-BN-modified TC4 titanium alloy micro-arc oxide coatings

Abstract

In this study, ceramic coatings were prepared on the surface of TC4 titanium (Ti) alloy by micro-arc oxidation (MAO). The morphology, element distribution and phase composition of MAO coatings were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and other analytical methods. The effect of hexagonal boron nitride (h-BN) doping on the wear resistance and corrosion resistance of the MAO layer was studied. The results showed that the coating was mainly composed of rutile titanium dioxide (TiO2), anatase titanium dioxide and a small amount of h-BN. Furthermore, the composite coating containing h-BN was less porous than the particle-free coating. The test results showed that h-BN doping slightly affected the hardness of the MAO coating, and it was helpful in improving the thickness, corrosion resistance and wear resistance of the coatings. When the amount of h-BN was 3 g/l, the corrosion current density of the coating was the smallest. When the addition of h-BN was 1.5 g/l, the friction coefficient of the coating was the smallest. The wear mechanism was adhesive wear, accompanied by slight abrasive wear.