The effect of nanoscale SiC particles on the microstructure of Al2O3 ceramics

The hot-pressing temperature, matrix grain size, fracture mode and the distribution of SiC were studied to reveal the effect of SiC inclusions on the microstructure of Al2O3. Al2O3–SiC composite powder was prepared by the precipitation method. Nanoscale SiC particles were coated with Al2O3. After hot pressing, most of nanoscale SiC particles were randomly located within the Al2O3 grains. SiC inclusions raised the hot-pressing temperature, decreased Al2O3 grain size, and inhibited the abnormal grain growth of Al2O3. The intergranular fracture for Al2O3 was transformed to the intragranular fracture for Al2O3–SiC nanocomposites because of the addition of SiC. All those microstructure changes increased the mechanical properties of Al2O3-composites by 40%.