It was previously reported by the present authors that, comparing the cutting performance of Al₂O₃-SiC powder ceramics tool with Al₂O₃-SiC whisker one, the flank wear of the former became smaller than that of the latter. Then, the study was undertaken to describe this reason, paying attention to the difference in the interfacial reaction between works and two sorts of ceramics. Diffusion couples consisting of pure nickel and ceramics were prepared in Ar at 1173-1573 K under 33 MPa, and microstructures near the interface were closely investigated.
Reaction (diffusion) layer containing an array of thin compound (Ni₃Si, Ni₅Si₂, etc.)-layers was clearly observed inside the ceramics commonly in both ceramics. In SiC whisker (SiC(w)) added ceramics, the thickness of diffusion layer became larger, and that of compound layer and the spacing of this layer became smaller, compared with those of SiC powder (SiC(p)) added ceramics. The above phenomena in SiC(w) added ceramics were considered to be due to the fact that diffusion of Ni into ceramics was enhanced owing to the anisotropic array of SiC(w). The increase in the flank wear was assumed to be related to the phenomena.