Characterization of Plasma Sprayed Hydroxyapatite Coating

In the experiment, hydroxyapatite coatings were obtained by using vacuum plasma spraying system. XRD and SEM were used to estimate the as received coating. The results indicated that, both amorphorization and thermal decomposition of hydroxyapatite took place in the process of plasma spraying. Amorphous phase was formed due to rapid cooling of the melted hydroxyapatite droplet. The thermal instability of hydroxyapatite at temperature 1300-1400℃ caused a decomposition of HA powder into CaO and TCP. A rough-surfaced coating was obtained by plasma spraying. Pores and microcracks were observed as the characteristics of as received coating. A sintering process between the splats occurred in the process, which was caused by the degradation of thermal exchange property between coating and titanium substrate.