Fabrication of a hydroxyapatite-containing coating on Ti-Ta alloy by electrical discharge coating and hydrothermal treatment

This study presented a method to surface-modify titanium alloy by electrical discharge coating (EDC). A hydroxyapatite (HA)-containing coating was formed on a 70Ti-30Ta alloy using EDC followed by hydrothermal treatment. Distilled water with HA powder was used as a dielectric medium in the EDC process. The microstructure, chemical composition, surface roughness, and wettability of the coating were characterized. The surface of the coating comprised Ti and Ta oxides and contained Ca and P. The thickness of the coating was approximately 7 μm. After hydrothermal treatment at 150 °C, the incorporated Ca and P precipitated to form petal-like HA crystals on the coating surface. The HA-containing coating exhibited hydrophilic tendencies.