The effect of calcination and zirconia addition on HAp hot pressed materials

The effect of 5 and 10 vol% additives of zirconia (3Y TOSOH) to hydroxyapatite of natural origin was investigated. Two types of powders were applied; one prepared by mechanical mixing of constituents and the other by calcination at 900 °C of such mixtures followed by their milling. Calcined powders lead to the lower level of hydroxyapatite decomposition during hot pressing at 1200 °C. Hydroxyapatite, cubic zirconia and β-TCP (β-Ca3(PO4)2) were found in the composites. Essential improvement of hardness, fracture toughness and mechanical strength compared to HAp matrix properties occurred. In the case of the material with 10 vol% zirconia additive the preliminary calcination of the starting powder resulted in better properties than in the case of the as-received powder.