Preparation and Property of Modified Micro-arc Oxidation Coating Using Al2O3 Particles on Ti6Al4V

Micro-arc oxidation is a new surface treatment method, but the structure of the micro-arc oxidation coating is restricted by the electrolyte composition. The micro-arc oxidation coating on Ti6Al4V alloy was modified by adding micro-Al2O3 particles to a sodium phosphate solution. The coating structure and phase were characterized by scanning electron microscopy and X-ray diffraction, and the oxidation resistance and thermal shock properties of the coating were investigated. Results show that the modified coating is denser than the original coating, which is composed of Al2TiO5 and TiO2. The oxidation resistance and thermal shock property of the coating are improved with addition of Al2O3 particles in the electrolyte compared to those of the samples prepared without particles added in the electrolyte. Moving Al2O3 particles are adsorbed on the coating surface and penetrate through it. As a result, the phase structure and properties of the original coating are modified.