Fabrication and microstructure of Al 2O 3–ZrO 2(3Y)–SiC nanocomposites

Abstract

Al 2O 3–ZrO 2(3Y)–SiC composite powder was prepared by the heterogeneous precipitation method. Calcinating temperature of the powder was important to obtain dense sintered body. The nanocomposites were got by hot-pressing, and addition of ZrO 2 did not raise the sintering temperature. Some Al 2O 3 grain shape was elongated, and Al 2O 3 grain size was about μm. Nano SiC particles were observed uniformly distributing throughout the composites, and most of them were located within the matrix grains. Because SiC particles located within ZrO 2 grains influenced the phase transformation of ZrO 2, the sintering of nanocomposites, which controlled grain size and transformable ZrO 2 amount, become important to get high performance. The strength of 80 wt% Al 2O 3–15 wt% ZrO 2–5 wt% SiC nanocomposites was 555 MPa, and toughness was 3·8 MPa m 1/2, which were higher than those of monolithic Al 2O 3 ceramics. ©