FORMATION AND SINTERING OF YTTRIA-DOPED TETRAGONAL ZIRCONIA WITH 50 MOL-PERCENT ALUMINA PREPARED BY THE HYDRAZINE METHOD

Al2O3/Y2O3-doped ZrO2 composite powders with 50 mol% Al2O3 are prepared by the hydrazine method. As-prepared powders are mixtures of AlO(OH) gel and amorphous ZrO2 solid solutions containing Y2O3 and Al2O3. The formation process leading to alpha-Al2O3-t-ZrO2 composite powders is examined. Hot isostatic pressing is performed for 2 h at 1400-degrees-C under 196 MPa using theta-Al2O3-t-ZrO2 composite powders. The resulting dense, sintered alpha-Al2O3-t-ZrO2 composites show excellent mechanical strength.