Process and wear behavior of monolithic SiC and short carbon fiber-SiC matrix composite

The process and wear behavior of monolithic SiC and 10 vol. % short carbon fiber-SiC matrix (C-SiC) composite have been studied. The results indicate that, among ethyl alcohol, acetone, n-hexane and n-octyl alcohol, n-octyl a lcohol was the most effective dispersing agent in dispersing both SiC powde r and short carbon fiber. Among AlN, Al2O3, B4C, graphite, AlN/B4C, AlN/gra phite, B4C/graphite and Al2O3/B4C, the most effective sintering aid for the fabrication of SiC and C-SiC composite was a mixture of 2 wt% AlN and 0.5 wt% graphite. The monolithic SiC hot-pressed at 2100 degrees C exhibited hi gher density but tower flexural strength than those hot-pressed at 2000 deg rees C due to a grain growth effect. For the C-SiC composite, both density and strength of the composite hot-pressed at 2100 degrees C were generally higher than those hot-pressed at 2000 degrees C. The density and strength o f C-SiC composite were lower than those of monolithic SiC under the same ho t pressing conditions due to a higher porosity level in the composite. When monolithic SiC slid against C-SiC composite, the weight losses of SiC and the composite were each less than that of self-mated SiC or self-mated C-Si C. In the self-mated SiC tribosystem, a mechanically stable film could not be established, resulting in an essentially constant wear rate. When slidin g against C-SiC, a thin, smooth and adherent debris film was quickly formed on the SiC surface, resulting in a lower wear. (C) 2000 Kluwer Academic Pu blishers.