A study of P-N compound as multifunctional lubricant additive

A novel P-N compound was synthesised, and its tribological and anti-oxidation behaviours used as lubricant additive for polyalphaolefins (PAO4) were evaluated. The results demonstrate that adding only low amount (<2 wt.%) of P-N compound into PAO4 could improve its anti-wear performance by 10 times, enhance its load-carrying capacity and oxidative stability, verifying the P-N compound is a kind of multifunctional and high-performance additive. The morphology and the chemical composition of the worn surfaces were characterised by scanning electron microscopy and X-ray photoelectron spectroscopy, indicating that the excellent anti-wear and load-carrying performance could be attributed to the forming of boundary lubrication film composed of iron oxide, iron phosphate, organic phosphine and organic amine, and so on. The work reported here is helpful to pave the practical applications and to understand the action mechanism of the multifunctional lubricant additives.