Undoped and diamond-doped MAO coatings prepared on Ti6Al4V: Microstructure, wear, corrosion, and biocompatibility properties

In order to improve the wear resistance and biocompatibility, undoped and diamond-doped micro-arc oxidation (MAO) coatings are prepared on Ti6Al4V in this paper by using electrolyte without/with diamond nanoparticles. The microstructure, wear resistance, corrosion resistance, and cytocompatibility performance of the coatings are studied and compared. The results show that undoped and diamond-doped MAO coatings have similar surface morphologies and thicknesses. With the increase of the MAO time, the surface morphology of the two types of coatings translates from the micro-sized traditional volcano pores into Micro/Nano-pores composite structure. The diamond-doped MAO coatings have higher wear resistance than the undoped MAO coatings and the original Ti6Al4V substrate. All the MAO coatings have higher corrosion resistance than the Ti6Al4V substrate. However, the diamond doping has no obvious influence on the corrosion resistance. In vitro assays indicate that both the two kinds of MAO coatings have a better ability to enhance the adhesion, spreading, proliferation, and osteogenic differentiation of MC3T3-E1 osteoblasts compared with the original Ti6Al4V substrate. Considering the high wear resistance, the diamond-doped MAO coatings are more promising for Ti6Al4V alloy.