PREPARATION OF ELONGATED DIOPSIDE/HYDROXYAPATITE COMPOSITE AND THEIR CELL-CULTURE TEST

Preparation of hydroxyapatite (HAp) with elongated diopside grains was studied. Diopside powder with a composition of CaO 23.3 mass%, MgO 14.2 mass%, SiO2 62.5 mass% was added to HAp powder (BET value was 65 m(2)/g) and sintered at 1280 degrees C for 2 h. These powders were selected to control the reaction of HAp and diopside and to obtain composites with elongated diopside grains. The bending strength of HAp-diopside composite containing 60 vol% diopside was 265 MPa and the fracture toughness was 3.2 MPa . m(1/2) These values were about 2 or 3 times higher than those of HAp. The increase in bending strength of the composite was attributed to an increase in fracture toughness. It was proved that diopside has no general toxicity cell culture. It is expected that HAp-diopside composite ceramics are useful for artificial bone and dental root.