Investigation on the tribocorrosion behavior of casting and spark plasma sintering Ni20Cr alloys in 3.5 wt% NaCl solution: Grain size effects

Tribocorrosion tests were performed on the Cast and SPS Ni20Cr alloys sliding against Si 3 N 4 in 3.5 wt% NaCl solution to investigate the grain size effect on the synergy of corrosion and wear. An appealing result was that the SPS alloy with finer grains exhibited less intense corrosion-induced wear, but more severe wear-induced corrosion, compared to the coarse-grained Cast alloy. The mechanism responsible for the significant difference was attributed to the composition and microstructure of the tribo-layer influenced by grain refinement. The finer grain structure facilitated the rapid replenishment of thicker Cr-rich tribo-layer, while meanwhile the dense layer exhibited high hardness and greatly reduced the wear rate of SPS alloy.