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 (TiO 2 ), 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.