Effect of Powder Sanding Process on Microstructure and Properties of 95Al₂O₃Ceramics Sintered with SiO₂-ZrO₂-MgO-CaO Aid

The morphology of the Al₂O₃ powder milled by sanding process and the composition, microstructure, and mechanical properties of 95Al₂O₃ ceramics prepared by sintering the powder with SiO₂-ZrO₂-MgO-CaO sintering aid were studied, and compared with those milled by planetary ball. The results show that the average particle size of Al₂O₃ powder after sanding was 0.2 μm, indicating that sanding had a significant refining effect on powder; the median particle size after planetary ball milling was 2.4 μm, which was similar to that of powder without milling. The phases of the ceramics prepared by sintering powder with sanding were Al₂O₃, Al_0.52Zr_0.48O_1.74 and m-ZrO₂, and those prepared by sintering powder with planetary ball milling and without milling were Al₂O₃ and a small amount of m-ZrO₂. The Al₂O₃ grains on surface of the ceramics prepared by sintering powder with sanding did not grow abnormally, and the ZrO₂ phase was pinned at Al₂O₃ grain boundaries; the Al₂O₃ grains prepared by sintering powder with planetary ball milling and without milling grew abnormally. The fracture toughness of ceramics prepared by sintering powder with sanding was (4.6±0.6) MPa·m^1/2, and was higher than those prepared by sintering powder with planetary ball milling and without milling.