Effect of Pulsed Laser Remelting Power on Wear Resistance and Corrosion Resistance of Biomedical Ti6Al4V Micro-Arc Oxidation Coating

The objective of this study was to further improve the wear and corrosion resistance of biomedical Ti6Al4V alloy micro-arc oxidation coating, so as to improve its comprehensive service performance. In this study, the effects of pulsed laser power (20–100 W) on the structure, composition, tribological properties and corrosion resistance of the composite coating were systematically studied by using pulsed laser remelting pretreatment technology. The results show that when the power is 100 W, the microwave stripe and fine grain structure formed by pulsed laser remelting can improve the discharge uniformity during the micro-arc oxidation process. The porosity of the composite coating decreases from 21.32% to 10.94%, and the thickness increases from 8.14 μm to 19.49 μm, which is beneficial to improve the compactness and uniformity of the micro-arc oxidation coating. In addition, the pulse laser remelting pretreatment increased the surface hardness of the composite coating to 745.5 HV, and the friction coefficient decreased from 0.76 to 0.51, thereby improving the wear resistance of the composite coating. The electrochemical test results show that the corrosion current density of the composite coating is reduced from 7.28 × 10−8 A·cm−2 to 1.91 × 10−8 A·cm−2 due to the optimization of the composite coating structure, and the corrosion resistance is significantly enhanced. This study provides an effective pretreatment strategy for the construction of high-performance MAO composite coatings.