Optimization of the coating parameters for micro-arc oxidation of Cp-Ti

TiO2 coatings were formed on the surface of CP-Ti by AC pulse micro-arc oxidation. The structural, mechanical, corrosion and tribological properties were analyzed by using XRD, SEM, microhardness tester, surface profilometer, electrochemical polarization unit and pin-on-disk tribotester. Potential, solution, frequency and duration time were chosen as the coating parameters and three levels for each parameter were determined. By determining the corrosion current density, corrosion potential, wear rate, friction coefficient and surface hardness, the optimum working conditions were determined by using a Taguchi design of experiment. After micro-arc oxidation, the aim is to minimize current density, the friction coefficient and the wear rate and to maximize corrosion potential and surface hardness after micro-arc oxidation. While the optimum conditions were determined, due to existence of more than one goal, a trade-off among goals was considered. First of all, each goal was optimized separately, and then all the goals were optimized together, considering the priority of the goals.