SLIDING WEAR OF SELF-MATED AL2O3-SIC WHISKER-REINFORCED COMPOSITES AT 23-1200-DEGREES-C

Microstructural changes occurring during sliding wear of self-mated Al2O3-SiC whisker-reinforced composites were studied using optical, scanning electron Microscopy and transmission electron microscopy. Pin-on-disc specimens were slid in air at 2.7 m s-1 sliding velocity under a 26.5 N load for 1 h. Wear tests were conducted at 23, 600, 800 and 1200-degrees-C. Mild wear with a wear factor of 2.4 x 10(-7) - 1.5 x 10(-6) mm3 N-1 m-1 was experienced at all test temperatures. The composite showed evidence of wear by fatigue mechanisms at 800-degrees-C and below. Tribochemical reaction (SiC oxidation and reaction Of SiO2 and Al2O3) leads to intergranular failure at 1200-degrees-C. Distinct microstructural differences existing at each test temperature are reported.