二烷基二硫代磷酸镧与硼酸酯的协同减摩抗磨作用机理

用四球摩擦磨损试验机考察了油溶性二烷基二硫代磷酸镧(LaDDP)和有机硼酸酯(OB)的减摩抗磨性能，探讨了LaDPP与有机硼酸酯的协同减摩抗磨作用及其协同摩擦化学反应机理；采用X射线光电子能谱仪和俄歇电子能谱仪对比分析了磨斑表面典型元素组成、化学状态和深度分布。结果表明，LaDDP和有机硼酸酯具有优良的减摩抗磨性能，且二者具有优异的协同减摩抗磨作用，其主要原因在于稀土元素镧促进了有机硼酸酯的分解及硼的渗透，生成了由La、La2O3、B2O3、FeS、硫酸盐和磷酸盐等组成的边界润滑膜，形成了镧与硼的渗透层。

Synergistic Friction-Reducing and Antiwear Effect of Lanthanum Dialkyldithiophosphate and Boric Acid Ester

Lanthanum diakyladithiophospate (LaDDP) and boric acid ester (OB) were synthesized. The tribological behaviors of the synthetic products as additives in ISOVG68 machinery oil were investigated on a four-ball machine, while the synergistic tribochemical effects of the two additives were explored based on the analyses of the worn steel surfaces by means of X-ray photoelectron spectroscopy and Auger electron spectroscopy. It was found that both the LaDDP and OB as additives functioned to significantly improving the friction-reducing,antiwear, and extreme-pressure properties of the base stock, which was attributed to the formation of a boundary lubricating and protective film composed of iron oxides and B_2O_3 or of iron oxides, FeS, FeSO_4, and FePO_4, by way of the tribochemical reactions among the additives,the atmospheric O_2, and the frictional pair. The combined additive of the LaDDP and OB was more effective to increasing the friction-reducing, antiwear, and extreme-pressure properties of the base stock, than the individual additive. This was because the tribochemical reaction products of the LaDDP acted to catalyze the decomposition of boric acid ester and promote the diffusion of the resulting B-containing products into the sub-worn-surface. It was therefore concluded that the LaDDP and OB had synergistic friction-reducing, antiwear, and extreme-pressure properties actions, which determined the better tribological behaviors of the combined additive than each individual one.