Effect of Bond Coat on Plasma Sprayed Aluminum Oxide Reinforced Hydroxyapatite Composite Coating

To improve mechanical properties of hydroxyapatite coatings, 10 and 20 wt% aluminum oxide was reinforced to HA and plasma sprayed onto metallic substrate. An intermediate layer of bond coat was applied to further enhance bond strength between coating and substrate and to reduce elemental diffusion from substrate to coating. The ASTM C633 79 pull off test was utilized to evaluate bond strength of coating. The coatings were characterized using SEM, XRD and EDAX techniques. Enhancement of mechanical properties were found by both reinforcement and by incorporation of bond coat. The bond coat efficiently reduced the diffusion of substrate elements to coating.