Friction properties and lubrication mechanism of self-lubricating composite solid lubricant on laser textured AISI 52100 surface in sliding contact

The frictional behaviour and lubrication mechanism of self-lubricating Gr-MoS2-PI-CNT composite were investigated experimentally, characterised by surface preparation method and texture density. The results indicate that the dimples filled with composite solid lubricant (sample TPL) exhibited the best lubrication mechanism with the lowest friction as compared to the smooth surface without lubrication (sample S), textured surface without lubrication (sample T), textured surface burnished with solid lubricant (sample TSL) and textured surface coated with solid lubricant block (sample TBL). The texture density of 41.7% exhibited good friction properties under both higher loads and speeds. The composite solid lubricant formed stable lubricant-peaks on each dimple the by 'slide extrusion accumulation' mechanism with a gradient phenomenon along the sliding direction which improved the self-lubricating effect of the lubricant. The energy dispersive X-ray spectroscopy (EDS) analysis indicates that the solid lubricant has been transferred from the micro-dimples to the space between dimples which improved lubrication.