Effect of zirconia addition on the microstructural evolution of porous hydroxyapatite

In the present study, 0–5 vol.% of 230 nm zirconia particles was added into hydroxyapatite (HAp). Though the reaction between HAp and ZrO2 has taken place, HAp remains after sintering at 1300 °C. The addition of zirconia reduces not only the sintering shrinkage, but also decreases the size of HAp grains. Both the strength and toughness of porous HAp decrease slightly due to the formation of CaZrO3 phase.