Microstructure and Mechanical Properties of Non-Staichiometric Apatite Ceramics and Sinterability of Raw Powder

Sinterability of non-stoichiometric calcium hydroxyapatite (Ca-HAP) prepared by the conventional solution reaction was studied, and microstructure and mechanical properties such as compressive strength, Vickers hardness, and fracture toughness of sintered bodies were examined. Sinterability and grain growth rate of Ca-HAP decreased with decreasing Ca/P ratio. Tricalcium phosphate (TCP) formed in the sintering gracess of the non-stoiohiometric Ca-HAP The amount and morphology of TCP were dependent on the Ca/P ratio. The non-stoichiometric Ca-HAP with Ca/P=1.655 heat-treated at 1100°C gave compressive strength and frapture toughness higher than those in literatures. The maximum compressive strength (mean value) and fracture toughness (mean value) were 10300kgf/cm2 and 1.52MPa·m1/2, respectively.