Preparation of a ZrO_2-Al_2O_3 nanocomposite by high-pressure sintering of spray-pyrolyzed powders

摘要

ZrOz-AlzO_3 powders were synthesized by spray pyrolysis. These powders were sintered at 1 GPa in the temperature range of 700- l l00 deg C. The microstructural evolution and densification are reported in this paper. The application of l GPa pressure lowers the crystallization temperature from ~850 to <700 deg C. Similarly, the transformation temperature under l GPa pressure for γ →α-Al_2O_3 reduces from ~ ll00 to 700-800 deg C range, and that for t → m ZrO_2 reduces from ~- l050 to 700 -800 deg C range. It was possible to obtain highly dense nanocrystalline ZrO_2-Al_2O_3 composite at temperatures as low as 700 deg. C. The effect of high pressure on nucleation and transformation of phases is discussed.