A tribological study of an S,P-containing benzotriazole derivative as an additive in pentaerythritol ester

The load-carrying capacity, antiwear and friction reduction properties of an S,P-containing benzotriazole derivative (BMDDP) added to a synthetic lubricant (pentaerythritol ester) were evaluated using a four-ball test machine. The results when compared with those of tricresyl phosphate (TCP) and zinc dialkyldithiophosphate (ZDDP) show that, in pentaerythritol ester, the novel compound (BMDDP) is an excellent multifunctional additive, which possesses better load-carrying capacity, antiwear and friction reduction properties than either TCP or ZDDP. The rubbed surfaces were analysed using XPS and EPMA, and the antiwear mechanism is discussed.