Phase analysis and thermal stability of hot isostatically pressed zirconia-hydroxyapatite composites

Composites of zirconia and hydroxyapatite (OHAp) have been processed via ho t isostatic Dressing (HIP) or sintering in air. When the composites were si ntered in air at a temperature of 950 degreesC, decomposition of the OHAp t o tricalcium phosphate occurred. Using the KIP technique, composites withou t any detectable degradation of the OHAp phase were produced at 1200 degree sC. The reactivity between zirconia and OHAp was dependent on both the amou nt of water lost from OHAp and the geometry of the interaction. The phase c omposition of the materials prepared was evaluated from their powder X-ray diffraction patterns, and their microstructures were studied via electron m icroscopy.