Effect of Microstructure on Sliding‐Wear Properties of Liquid‐Phase‐Sintered α‐SiC

We have studied, for the first time, the effect of the content of intergranular phase and grain size on the sliding‐wear resistance of pressureless, liquid‐phase‐sintered (LPS) α‐SiC (silicon carbide) ceramics. It was found that the sliding‐wear behavior of these ceramics is similar to what is observed in other polycrystalline ceramics: initial mild, plasticity‐controlled wear followed by severe, fracture‐controlled wear, with well‐defined wear transition. We have found that the increase in the content of intergranular phase and the grain coarsening leads to the degradation of the sliding‐wear resistance in LPS α‐SiC ceramics. A mechanistic model is used to rationalize these wear results, and to provide guidelines for the design and fabrication of low cost, highly wear‐resistant SiC‐based ceramics. This is likely to have important implications because SiC‐based materials are being used increasingly in contact‐mechanical and tribological applications.