Tribological behaviors of steel surfaces treated with ion sulphurization duplex processes

Low temperature ion sulphurization process and its duplex treatments combining with ion-nitriding and shot-peening were used to treat 1045 steel. The anti-scuffing, friction-reducing and wear-resistant behaviors of these treated surfaces were investigated using a ball-on-disc tester under engine oil lubrication conditions. SEM, EDX, XRD, and AES were used to examine the morphologies and compositions of layers, and wear scars. The results show that sulphurization duplex treatments can improve the anti-scuffing behavior obviously. Nitrided + sulphurized layer has the highest load bearing capacity and lowest wear volume, but it intensifies the wear of counterpart. Thus the nitriding + sulphurization treatment is more beneficial to the treated surface itself. Shot-peening + sulphurized layer has the lowest friction coefficient and induces the lowest wear volume of counterpart. Thus the shot-peening + sulphurization treatment is more beneficial to counterpart surface.