Effect of Hybrid Surface Treatment Composed of Plasma Nitriding and DLC Coating on Friction Coefficient and Fatigue Strength of Stainless Steel

Abstract

This study was conducted to investigate the effect of hybrid surface treatment composed of plasma nitriding and DLC (diamond-like carbon) coating on the friction coefficient and fatigue strength of stainless steel JIS SUS316. The obtained results were compared with the results of the previous study which investigated the effect of hybrid surface treatment composed of plasma carburizing and DLC coating. Plasma nitriding as a pretreatment was more effective to decrease the friction coefficient of DLC-coated stainless steel than plasma carburizing because the hardened layer with greater hardness supported the DLC layer. The mechanical properties were unaffected by both hybrid surface treatments. Plasma nitriding improved the fatigue strength of stainless steel more than plasma carburizing. DLC coating slightly improved the fatigue strength of the plasma-nitrided material; however, its effect was more significant on the plasma-carburized material.