Dopant-dependent diffusion behavior of SiAlON ceramics against Inconel 718 superalloy

The utilization of SiAlON ceramics at high speed machining of superalloys has been increasing day by day. In these operations, chemical wear, based on diffusion of tool and work-piece atoms towards each other due to high temperature and pressure at the cutting zone, is the dominant tool failure mechanism. In this study, dopant-dependent diffusion behavior of SiAlON ceramics, prepared by using different rare-earth elements (Y, Yb, Er and Ce), against Inconel 718 alloy was investigated. The SiAlON-Inconel 718 diffusion couples were manufactured by SPS technique. It was observed that the diffusion zone thickness was strongly dependent on the type of the rare-earth used in the composition and Er-doped SiAlON samples had a higher interaction zone in comparison to the others. Moreover, crystallization of grain boundary phase was observed as an effective parameter on the zone thickness for Er-doped compositions.