Effect of fine particle peening using carbon-black/steel hybridized particles on tribological properties of stainless steel

• Fine particle peening to enrich the surface with carbon black is developed.
• Surface modified with carbon black shows a low and steady friction coefficient.
• Carbon-black tribofilm is formed on the wear scar of the modified surface.
• Carbon black weakly bonded to the surface is necessary for the tribofilm formation.
• We propose a new surface treatment promising excellent tribological properties.

A new fine particle peening (FPP) using carbon-black/steel hybridized particles was developed to improve the tribological properties of stainless steel. FPP using the hybridized particles induced the transfer of carbon black from the particles to the surface. The FPP-treated specimen exhibited a low friction coefficient and little wear because carbon black, acting as a lubricant, was present on the contact surfaces between the specimen and the reciprocating ball used in the test, even after the original FPP-treated surface was worn away. The mechanism of the developed FPP process and its beneficial effect on the tribological properties were clarified.