Effect of Na₂SiO₃ addition in the electrolyte on the thickness and surface micro-morphology of micro-arc oxidation coatings formed on Ti6AI4V

Coatings were obtained by micro-arc oxidation on the surface of a Ti6A14V alloy in the electrolyte contained different contents of Na₂SiO₃. The surface micromorphology and roughness of coatings were analyzed by SEM and AFM, and the effects of Na₂SiO₃ content on the thickness and surface micromorphology of coatings were investigated. The results show that the thickness of coatings increases from 31 μm to 88 μm and the critical arcing forward voltage decreases gradually when the mass concentration of Na₂SiO₃ in the electrolyte increases from 12g·L^-1 to 28g· L^-1. There are many microholes with different sizes on the surface of coatings, and the amount of microholes and the roughness of coatings increase as the content of NaaSiO3 in the electrolyte increasing. It is found by X-ray diffraction analysis that the coatings are composed of anatase and ruffle.