Lubrication mechanism analysis of nickel-carbon-based tribological layer on sliding interfaces in automotive engines

Automotive engine oils demand superior tribological properties to prolong the lifespan of mechanical components. This study contributes to that objective by investigating the impact of nickel-coated multi-walled carbon nanotubes (Ni-MWCNTs) as additives to engine oil on tribological properties. Tribological tests were conducted utilizing a reciprocating motion tribometer to simulate the tribo-system of the piston ring and cylinder liner in automobile engines. Additionally, advanced characterization techniques were employed to study wear and lubrication mechanisms. Ni-MWCNTs nano-additives diminished the friction coefficient and wear rate by 15-23% and 68-87%, respectively, compared to baseline oil. The lubrication process is ascribed to the generation of a tribofilm brought about by thermophysical and tribochemical mechanisms. Ultimately, this study offers new insights into improving lubrication performance in automobile engines to enhance engine durability and fuel economy.