One step synthesis of ZnO nanoparticles from ZDDP and its tribological properties in steel-aluminum contacts

In order to overcome the poor lubricity of zinc dialkyldithiophosphate (ZDDP) in aluminum contacts, ZnO nanoparticles (ZODDP) modified with dialkyldithiophosphoric acid were prepared through one step process from ZDDP. Compared with ZDDP the sulfur and phosphorus contents of ZODDP decreased by 77.9%～82.8% and 77.3～80.7%. respectively. The tribological properties of ZODDP as the additives of diisooctyl sebacate (DIOS) in steel-aluminum contacts were evaluated on ball-on-disk tribometer. Compared with ZDDP the friction coefficient (cof) and wear rate (wr) of ZODDP decreased by 10.37% and 71.74% respectively. The ZnO nano cores in ZODDP enriched on frictional surface, which avoided the direct contact between friction pairs. The weak chemical interaction between ZnO nano-core and modifier promoted the tribological reaction between modifier and aluminum disks. ZODDP is expected to be a cheap and easily available lubricant additive for aluminium-based materials lubricating. •An environmentally friendly nano-additive ZODDP was prepared by in situ oxidation of ZDDP through simple one-step process.•Compared with ZDDP the sulfur and phosphorus contents of ZODDP decreased by 81.63% and 78.55% respectively.•Compared with that of ZDDP the cof and wr of ZODDP as additives in DIOS decreased by 10.37% and 71.74% respectively.•Nano-additive ZODDP overcomes the problem that ZDDP cannot form effective friction film on aluminum-based friction pair.