Hydroxyapatite of natural origin-zirconia composites, preparation and reactions within the system

Abstract

The effect of 5 and 10 vol.% addition of zirconia (3Y-TOSOH) to hydroxyapatite of natural origin was investigated. The hydroxyapatite (HAp) material was extracted from the bovine bones by treatment under hydrothermal conditions with distilled water. The pure HAp and HAp-ZrO2 composites were manufactured by pressureless sintering and hot pressing. The reactions taking place in these systems were observed using the X-ray diffraction, infrared spectroscopy and dilatometric observations. It was confirmed that the extent of the reactions was essentially dependent on the heat treatment method. Under the hot pressing conditions dense samples containing high fraction of unreacted HAp could be prepared at 1200 °C.Mechanical properties of the pure HAp and HAp-ZrO2 composites were also investigated. Zirconia inclusions lead to the increased strength, hardness and fracture toughness of the composites compared to the pure HAp polycrystalline materials.