Investigation of mechanical properties of TiN + MoS x coating on plasma-nitrided substrate

Abstract

To meet the increased demand from a coating–substrate system, it is desirable to use a substrate with higher load bearing capacity and a surface coating with low friction combined with improved wear characteristics. In the present work, the effects of duplex treatment consisting of plasma nitriding and TiN + MoS x coatings with and without graded interlayer on the mechanical and tribological properties of stainless steel substrate were investigated. Low-temperature plasma nitriding was performed with a new process (Saddle field fast atom beam source) and coatings were deposited by closed-field unbalanced magnetron sputtering. Energy dispersive X-ray spectroscope, microhardness tester, Rockwell C indenter and X-ray diffraction were used to evaluate coating composition and graded profile, microhardness and toughness, adhesion strength and structural phase, respectively. These properties were correlated with the tribological properties evaluated by pin-on-disk test. It was found that duplex coating system with graded interlayer exhibited overall enhanced mechanical and tribological properties compared to other combinations.