COMBINED PLASMA NITRIDING AND SURFACE TEXTURING FOR IMPROVING TRIBOLOGICAL PERFORMANCE OF 316 STAINLESS STEEL

Abstract

Combined plasma nitriding and surface texturing approach were conducted on 316 stainless steel to enhance the tribological performance. Five different surfaces (316 substrates, plasma-nitrided 316, surface-textured 316, plasma-nitrided surface-textured 316, and surface-textured plasma-nitrided 316) were investigated. The tribological behaviors were studied using a ball-on-disk rotary tribometer against counterparts of Si3N4 balls in the air and under oil lubrication conditions. The results were analyzed from the aspects of friction coefficient, mass loss, and surface morphology about the tested specimens. The results presented that the frictional properties of the surface of plasma-nitrided surface-textured 316 were optimal under both friction conditions. Under dry friction conditions, the influence of plasma nitriding on mass loss was greater than that of surface texturing. Under oil lubrication conditions, the influence of surface texturing on mass loss was greater than that of plasma nitriding, and the processing sequence of surface texturing and plasma nitriding had little effect on the mass loss. The better wear resistance of plasma-nitrided surface-textured 316 resulted from the following aspects: first, the nitriding layer improved the surface hardness of the material. Secondly, the surface texture can capture the debris under dry friction conditions and provide continuous lubrication under oil lubrication condition.