Plasma-Sprayed Hydroxyapatite-Bioactive Glass Composites on Ti6A14V

Hydroxyapatite(HA)-coated Ti6A14V has recently been used as a bone substitute in orthopaedic and dental applications because of its favorable bioactivity and mechanical properties. Studies in the literature have also shown that the bioactivity of calcium phosphate bioactive glass is higher than that of hydroxyapatite. In an attempt to increase the bioactivity of the HA-coated Ti6A14V and enhance the bonding strength between coating and substrate, in the present study, HA-bioactive glass (BG) composites are applied onto Ti6A14V using a plasma spray technique. Microstructure and phase changes of the HA-bioactive glass composites coatings after plasma spraying are studied. Coating-substrate bonding strength is evaluated using an Instron tester following ASTM C633 methods. Results indicate that the average bonding strengths for BG, HA/BG, and HA coatings are determined to be 33, 36, and 52 MPa, respectively. Open pores with sizes up to 50 (im are found in both BG and HA/BG composite coatings. When compared to the conventional HA coating, HA/BG composite coating on Ti6Al4V would provide a coating system with sufficient bonding strength, higher bioactivity, possible better mechanical interlocking with the surrounding bone structure when implanted, and a significant reduction in cost. The future of this HA/BG composite coating system seems pretty bright. Research on this composite system with other compositions is ongoing.