Electrochemical Polishing of Additively Manufactured Ti–6Al–4V Alloy

In this present paper, the electropolishing behavior of Ti–6Al–4V alloy fabricated by additive manufacturing in chloride-containing ethylene glycol electrolyte was surveyed. The impacts of chloride ion on surface quality and oxide film of Ti–6Al–4V were analyzed in dependence on the surface topography, roughness, weight loss ratio and compositions. The visual and microscopic results revealed that the optimally electropolished surface was attained in a 0.4 mol L⁻¹ chloride electrolyte with a decreased surface roughness of 75.04% and a weight loss rate of 4.93%. For lower (C_Cl⁻¹ ≤ 0.3 mol L⁻¹) or higher concentrations (C_Cl⁻¹ ≥ 0.5 mol L⁻¹), a smooth and flat surface was not observed due to insufficient reactions or excessive anodic dissolution. During the electropolishing, the titanium oxides nucleated and corresponding surface tension increased, resulting in the formation of a stable TiO₂ film on the surface of the Ti–6Al–4V alloy, increasing the corrosion resistance of the specimen.