LAUSR

Abstract 3 mol% yttria-partially stabilized zirconia (Y-TZP) powder and a sol-gel derived CaO- P 2 O 5 - SiO 2 (64S) bioglass, were used to produce Y-TZP- 64S slip cast compacts. The compacts with 10.5 and 19.9 vol% 64S were sintered at different temperatures up to 1500 °C using 5 and 10 °C/min heating/cooling rates. The densification behaviour, crystalline phase formation and zirconia grain growth were investigated as a function of sintering temperature and 64S glass content. Ca 3 (PO 4 ) 2 along with SiO 2 as a major phase were obtained from thermal decomposition of the 64S glass at 950–1500 °C. Both 64S additions, 10.5 and 19.9 vol%, promoted the sintering process at a lower temperature with respect to Y-TZP (1500 °C); the SiO 2 phase markedly increased the Y-TZP solid state sintering rate at the intermediate stage. The rapidly cooling at 10 °C/min inhibited the t-m transformation of Y-TZP and markedly reduced that of Y-TZP- 64S at 1300–1500 °C. Sintered Y-TZP with 10.5 vol% 64S, nearly fully densified at 1300–1400 °C, was constituted by polygonal ZrSiO 4 particles and elongated Ca 2 P 2 O 7 particles uniformly distributed in the tetragonal zirconia fine grain matrix. This ceramic exhibited similar hardness to that of Y-TZP sintered at 1500 °C; the in situ formation of calcium phosphate will have the potential to improve the Y-TZP biological properties without significantly affecting its hardness.