Dispersion of ZrO2 particles in the Al2O3/ZrO2 ceramics by the partial chemical dispersion processes

To improve the mechanical properties of Al2O3/ZrO2 composites, the homogeneous dispersion of ultra low size ZrO2 particles in Al2O3 ceramics have been controlled by partial dispersion of ZrO2 by chemical processes such as coprecipitation or polymeric precursor method(Pechini process). So nanosized Zr/Y hydroxide were coprecipitated or polymerized directly to the surfaces of commercial sub-micron size alpha-alumina powder(Sumitomo: AES-11 (0.4 mu m)) using ZrOCl2 /Y(NO3)(3) solution. By the partial coprecipitation method, dispersion of relatively small sized ZrO2 in Al2O3/ZrO2 composites could be achieved at 1500 similar to 1600 degrees C of sintering temperature. In case of the polyesterization of Zr/Y(NO3)(3)-citric acid solution in ethylene glycol directly to the commercial sub-micron size a-alumina powder, more homogeneous dispersion of relatively low sized ZrO2 in Al2O3/ZrO2 composites could be obtained at 1450 similar to 1600 degrees C of sintering temperature range and their mechanical strength was more enhanced.