MICROSTRUCTURE CONTROL AND WEAR OF AL2O3-SIC-(AL,SI) COMPOSITES MADE BY MELT OXIDATION

Ceramic matrix composites of Al2O3-SiC-(Al,Si) have been fabricated by directed melt oxidation of aluminum alloys into SiC particulate prefo rms. The proportions of Al2O3, alloy, and porosity in the composite ca n be controlled by proper selection of SLC particle size and the proce ssing temperature. The wear resistance of composites was evaluated in pin-on-disk experiments against a hard steel substrate. Minimum wear r ate comparable to conventional ceramics such as ZTA is recorded for th e composition containing the highest fraction of alloy, owing to the d evelopment of a thin and adherent tribofilm with a low coefficient of friction.