Al2O3-ZrO2 ceramics with submicron microstructures obtained through microwave sintering, plasma sintering and shock compaction

This paper reports that submicron and nanocrystalline grain sizes were achieved in the Al2O3-ZrO2 eutectic composition through conventional, microwave and plasma sintering of rapidly solidified starting powders and through shock compaction of commercial powders. Post sintering studies revealed nanocrystalline intragranular ZrO2 in the 1-2 μm Al2O3 grains, which is thought to be a result of the solidification synthesis. Additions of B2O3 greatly increased the final density through liquid phase sintering. Shock compression of commercial powders produced dense, crack-free, fine grained ceramics with loading pressures up to 9.1 GPa and a metastable ZrO2 phase under higher pressures