Reciprocating Wear Behavior of Ductile Cast Iron Modified by Pulse Plasma Technology

Wear resistance of ductile iron can be improved through different surface engineering techniques, each having some limitations and drawbacks. Recently, a new method called pulse plasma technology has been introduced, which through local reinforcement with inserts improves wear resistance of ductile iron without compromising other properties. This paper deals with the improvement of the wear resistance of ductile iron surface modified by pulse plasma technology using a tungsten electrode. The surfaces of the samples were treated by $C_3H_8$, air, and oxygen gases. The surface morphology and the phase structure in the near surface region of original and treated samples were analyzed with optic microscope, scanning electron microscope and energy-dispersive spectroscopy. The surface properties were evaluated by measuring the microhardness, wear properties and friction coefficient, as well as the elemental depth profiles and chemical composition of the modified layer. It was found that the microhardness of the treated samples was much higher. The tribological resistances were also significantly improved, as confirmed by the reduced friction coefficient and wear track width. This improvement can be attributed to the diffusion of tungsten on the surface layer.