Dispersion of Nano Size ZrO2 in Al2O3/ZrO2 Ceramics by Hydrolysis

Nano size ZrO2 dispersed in Al2O3/ ZrO2 composite ceramics have been fabricated by chemical routes for the improvement of mechanical properties. In case of mechanical mixing of Al2O3 with ZrO2 powder homogeneous dispersion and controlling the ZrO2 size were relatively difficult during sintering. So hydrolysis method for preparing zirconium hydroxide from ZrOCl2· 8H2O and Y(NO3)3 6H2O directly with commercial sub-micron sized α-alumina (Sumitomo:AES-11(0.5 μm)) was adapted, and by this method ZrO2 distribution was more uniform than mechanical mixing. But because of the relatively high sintering temperature of Al2O3 ceramics, dispersed ZrO2 particles grown up to 200 to 500 nm at sintering temperature of 1500∼1600°C. So in order to decrease the sintering temperature of Al2O3/ZrO2 ceramics, high purity α-alumina (Taimei Chemical (0.22 μm)) was used and dispersed ZrO2 particle size could be controlled below 200 nm at sintering temperature of 1400∼1500°C.