EFFECT OF MgO NANO PARTICLES ON SINTERING BEHAVIOR OF Al 2 O 3 - SiC - MgO NANO COMPOSITES

Abstract

Small amount of MgO in the range of ppm and distribution of SiC particles in Al 2 O 3 -10 vol % SiC nanocomposite has an obvious effect on improving of density and mechanical properties such as hardness of sintered nanocomposite. Improving of these properties continues to 1000 ppm of MgO , but decreases above this amount. Transgranularly fractured alumina grains were observed on the fracture surface of this kind of nanocomposites. The effects of such a small amount of MgO on the sintering and microstructural development of Al 2 O 3 -10 vol % SiC nanocomposite may be explained using the arguments which have been documented for the beneficial effects of a small amount of MgO in alumina ceramics. In Al 2 O 3 -10 vol % SiC nanocomposite, Al 2 O 3 particles were coated by nano scale SiC particles which inhibited the abnormal grain growth of Al 2 O 3 .