Consolidation and mechanical properties of nanostructured hydroxyapatite–(ZrO2 + 3 mol% Y2O3) bioceramics by high-frequency induction heat sintering

Hydroxyapatite and hydroxyapatite–yttria stabilized zirconia (3YSZ) with 20 vol%–(ZrO2 + 3 mol% Y2O3) nanopowders were consolidated very rapidly to full density by high-frequency induction heat sintering (HFIHS). Effects of temperature and the addition of 3YSZ on the toughness, hardness and microstructure properties have been studied. 3YSZ second phase toughening hydroxyapatite composites with higher toughness were successfully developed at relatively low temperatures through this technique. The samples were densified by heating to a sintering temperature in the range of 900–1200 °C, and then rapidly cooled to 500 °C within a very short time. A relative density of up to 98.6% of theoretical density of the composites was achieved after sintering at 1100 °C. Compared with hardness and toughness obtained for pure hydroxyapatite, the hardness and toughness for hydroxyapatite–20 vol% 3YSZ were much higher.