The Study on the Reducing Friction and Anti-Wear Performance of Zinc Phosphate Nanoparticles as Lubrication Additives

Abstract

Oleic acid-modified zinc phosphate nanoparticles with about 15nm particle size were synthesized by chemical deposition method. The tribological properties of the prepared nanoparticles as lubricant oil additives on MSR-10D four-ball tribotest were investigated. Results indicated that the lubricant oils adding oleic acid-modified zinc phosphate nanoparticles exhibited a good friction-reduction and anti-wear property. The zinc phosphate nanoparticle as lubricant oil additive had the optimum concentration. Friction coefficient decreased 14.2% maximally, and the wear-scar width reduced to 36.5% correspondingly, as compared to the base oil without nanoparticles. The results of the worn surface analysis with SEM and AFM showed that the zinc phosphate nanoparticles could deposit on the worn surface and separate the direct contact between the asperities of the worn surface, which was effective in the reduction of the plough and adhesion between asperities.