SINTERING OF HYDROXYLAPATITE ZIRCONIA COMPOSITE-MATERIALS

Sintering of hydroxylapatite-zirconia (doped with 3 mol% Y2O3) composite powder compacts was studied. Hydroxylapatite powder was prepared from Ca(OH)2 and H3PO4, and zirconia powder was prepared from ZrOCl2&middot8H2O and YCl3. The sinterability of hydroxylapatite-zirconia composite powder compacts depends on differential shrinkage between the powder components. Smaller differential shrinkage results in better sinterability. Increasing the calcination temperature of zirconia powder and/or decreasing that of hydroxylapatite powder improves sinterability. The phase distribution and total amounts of crystal phases depend on the sintered density. Hydroxylapatite and cubic zirconia are the major phases of compacts with high sintered densities, whereas α- and β-tricalcium phosphate and CaZrO3 are the major phases of compacts with low sintered densities.