Development of calcium phosphate based functional gradient bioceramics

A functional gradient bioceramic that can function gradually with respect to body tissue was studied by changing the composition of calcium phosphate gradually from the surface to the inside. Diamond powder was spread on the surface of compact hydroxyapatite (HA) powder and fired at 1280 °C under reduced pressure, followed by firing under atmospheric conditions. The sintered body thus prepared was dense and α-tricalcium phosphate (α-TCP: α-Ca3(PO4)2) was found on its surface. The content of α-TCP gradually decreased with increasing depth from the surface. In contrast, the content of HA increased with increasing depth from the surface. The gradient ratio of α-TCP and HA depends on the firing time for each condition, i.e. reduced or atmospheric pressure. The α-TCP formation was ascribed to the decomposition of HA due to the spontaneous combustion of diamond powder.