Tribological behavior of 316L stainless steel fabricated by micro powder injection molding

In this paper, 316L stainless steel micro-mixers were fabricated by micro powder injection molding. The tribological behavior of the stainless steel micro-mixer sliding against AISI 52100 steel at low loads was investigated using a ball-on-disk tribometer. The morphologies and compositions of the worn surfaces were analyzed by SEM, Raman and XPS. The results showed that the wear mechanism of stainless steel depended strongly on the microstructure which was influenced by the sintering atmosphere. The friction coefficients and wear rates of the stainless steel sintered in vacuum were lower than that in hydrogen, due to the formation of carbide phase in the former matrix. Tribo-oxidation together with the formation and delamination of tribo-layer were the dominant wear mechanisms for stainless steel sintered in vacuum. The tribo-layer composed of various iron oxides, such as Fe3O4, α-Fe2O3, γ-Fe2O3, and γ-FeOOH, which were favorable and caused mild wear. In the case of the stainless steel sintered in hydrogen, the worn surfaces were very rough with more wear debris entrapped. Adhesive wear was responsible for the material transfer from the stainless steel to the AISI 52100 steel, which led to the transition from mild to severe wear.