HEAT CONDUCTION OF COMPOSITES AND ITS DEPENDENCE ON THE MICROSTRUCTURE OF Al_2O_3-Cr_3C_2 COMPOSITE

摘要

Heat conduction behavior of Al_2O_3-Cr_3C_2 composite with Cr_3C_2 content varying from 0 to 40% in volume were investigated using a laser-flash method. Thermal diffusivity of the composite decreased sharply as first incorporating 10 vol.% of Cr_3C_2, then increased with further increase of Cr_3C_2 content up to 40 vol.%. Similar trends were observed for thermal conductivity behaviour. The significantly decreased thermal diffusivity as well as thermal conductivity at lower content of Cr_3C_2 was assumed to be ascribed mainly to the formation of "composite grain" wherein the fine Cr_3C_2 particle being trapped into Al_2O_3 grain. Furthermore, the formation of an amorphous layer with thickness approx. 10 A at inclusion/matrix interface may also act as a barrier to phonon conduction.