Structure and Corrosion of High Voltage Anodic Oxide Coatings on Ti6Al4V Biomaterial

Oxide coatings were produced on Ti-6Al-4V alloy by anodization process using two different aqueous electrolytes. The electrolytes contained calcium and phosphorus in the molar ratios of 5 and 15, respectively. Coatings were obtained by applying 250 and 300 V and were characterized by XRD and TEM. Properties like chemical composition, thickness and surface roughness were obtained. All the coatings contained TiO2 along with calcium and phosphorus. Electrochemical polarization and AC impedance studies were done in Simulated Body Fluid medium. The coating obtained by oxidation at 250 V from the bath maintained at Ca/P ratio of 5 had better corrosion properties. Improvement in corrosion resistance was attributed to the presence of phosphorus in the coatings.