Tribological Properties of Molybdenum Ion-Plated and Ion-Surfurized Composite Coating on Mild Steel

Mobased composite surfacemodifying coating containing MoS2 was prepared on 1045 steel by multiarc ion plating and low temperature ion sulfurization. The phase composition and elemental depth profiles of the resulting coatings were analyzed by means of Xray diffraction and Auger electron spectroscopy. The tribological properties of the composite coating sliding against SAE52100 steel under oillubricated condition were investigated on a QP100 friction and wear tester in a ballondisc contact configuration. The morphology of the coating was observed with an atomic force microscope, while its worn surface and crosssection morphologies were analyzed using a scanning electron microscope. As the results, the composite coating was composed of MoS2, Mo, and a small amount of FeS. The composite coating had much better frictionreducing and wearresistant ability than the Mo ionplated or ionsulfurized surfacemodifying layers. This was because the harder Moenriched subsurface had good support to the softer MoS2enriched superfacial layer, which contributed to reduce the friction and wear significantly.