Effect of heat-treatment temperature on HA-coated titanium materials

Homogeneous HA coating materials were prepared on porous titanium by the low-temperature combustion synthesis. It was found that the mechanical properties of the specimen depend on the coating process and the heat treatment, and the bending strength would be reduced during the coating process but could be improved by heat treatment. The effects of the temperature during heat- treatment on the phase composition and micro-structure of the as-prepared coating, and the bending strength of the specimen were investigated by XRD and SEM. The experimental results show that in the coating process, slight oxidation of the substrate may give rise to a drop in bending strength; however, it could be increased by the reaction of HA and TiO₂, and the sintering of the coating during heat treatment. The HA particles in the coating, with very fine sized particles, were pretty active and would decompose at 800°C.