Synergistic tribological effect between polyisobutylene succinimide-modified molybdenum oxide nanoparticle and zinc dialkyldithiophosphate for reducing friction and wear of diamond-like carbon coating under boundary lubrication

Abstract Organic molybdenum lubricant additive like dialkyl dithiocarbamate (MoDTC) can cause wear acceleration of diamond-like carbon (DLC) coating coupled with steel under boundary lubrication, which hinders its industrial application. Therefore, polyisobutylene succinimide (PIBS), an organo amide, was adopted to modify oxide affording succinimide-molybdenum nanoparticles (MPIBS-MONPs) potential prevent the DLC coating. The thermal stability MPIBS-MONPs evaluated by thermogravimetric analysis. Their tribological properties as additives in di-isooctyl sebacate (DIOS) were MoDTC a control; and their tribomechanism investigated relation tribochemical reactions synergistic effect zinc dialkyldithiophosphate (ZDDP) well worn surface characterizations. Findings indicate that MPIBS-MONPs/ZDDP added DIOS significantly reduce friction coating, being much superior MoDTC. This is because ZDDP jointly take part form composite tribofilm increase resistance Namely, amide on react MoS 2 film excellent friction-reducing ability; release nanoparticle deposited lubrication layer surfaces. as-formed consisting nanocrystal, amorphous polyphosphate, disulfide small amount Mo C accounts for lubrication.