The Tribological Characteristics and Mechanism of Several P-N Type Extreme Pressure and Antiwear Additives in Polyoxyethylene Glycol

In this paper several P-N type extreme pressure and antiwear additives are synthesized. The tribological properties of these additives in Polyoxyethylene Glycol are evaluated using two four-ball tribometers, and the tribofilms are investigated by the X-ray absorption near-edge structure (XANES) spectroscopy. The tribochemical mechanism of the additives are discussed. The results show that the additives have better anti-wear and friction reducing properties than the traditional P-N additive T308B in polyoxyethylene glycol, and the PN1 with shorter length alkyl chain has better anti-wear and friction reducing properties than others. XANES surface analysis results indicate that tribofilms are mainly composed of adsorbed layer and chemical reacted layer, and chemical reacted layer is constituted by phosphate and polyphosphate.