Effect of low-temperature plasma carburizing on surface topography, mechanical and tribological properties of sintered iron and nitrided sintered iron

This study investigated the effect of a low-temperature carburized layer on the topography, mechanical and tribological properties of sintered and nitrided sintered iron. Two nitride layers (γ’-Fe4N and ε-Fe2–3N) were produced by plasma nitriding. Subsequently, low-temperature plasma carburizing was used to develop a cementite layer over the samples. The carburized layer increased H/E* and H3/E*2 of the sintered iron more effectively than the nitride layers. The cementite layer improved the wear resistance of the iron by 45%, statistically similar to the γ ´ nitride layer. Postcarburizing enhanced the mechanical properties of the nitrided iron due to the formation of a duplex layer. However, the presence of pores at the interfacial region of the duplex layers induced a brittle wear mechanism. •The roughness of the Fe3C layer is 4x smoother than nitride layers.•Fe3C layer enhanced the iron’s H/E* and H3/E*2 ratios due to its high hardness.•Wear resistance of iron increased 45% after the low-temperature plasma carburizing.•Postcarburizing treatments improved the mechanical properties of iron nitride layers.•Pores at the interface of the duplex layers induced a brittle wear mechanism.