全配方发动机油SJ/5W-30中二烷基二硫代甲酸钼的摩擦学特性研究(Ⅱ)--二烷基二硫代甲酸钼(MoDTC)的摩擦化学效应

EDX分析表明，摩擦磨损过程中二烷基二硫代甲酸钼(MoDTC)中的活性元素与摩擦副材料表面发生了摩擦化学反应。温度和摩擦机械作用能显著促进：MoDTC与摩擦表面的摩擦化学作用。MoDTC的存在促进了全配方发动机油SJ／5W-30中的多功能添加剂ZDTP的分解。采用添加MoDTC的油样润滑时，在铸铁磨损表面上能形成Mo的化合物(MoO3，MoS2)以及硫化物(FeS)；纯基础油样SJ/5W-30润滑时铸铁磨损表面上只有硫化物形成，而且所形成的硫化物除FeS之外，还有较多的硫酸盐(FeSO4)。MoDTC与ZDTP甲复配时边界反应膜的形成可采用Pearson的硬软酸碱(HSAB)原理来阐释。

Study of Tribological Behavior of Molybdenum Dithiocarbomate (MoDTC) Blended into A Fully Formulated Petroleum Based Engine Oil (SJ/5W - 30) Part Ⅱ Tribo-chemical Effect of Molybdenum Dithiocarbomate (MoDTC)

EDX analysis of worn surfaces of nitrided coating and cast iron have evidenced that there were occurring in the friction and wear processes tribochemical reactions of the activated elements from molybdenum dithiocarbomate (MoDTC) with the surfaces of the tribomaterials, and, the tribochemical reactions between MoDTC and the tribo-surfaces can be enhanced by the temperature and tribomechanical action. In addition, MoDTC can promote the decomposition of ZDTP in the fully formulated engine oil. With the chemical identification by XPS of the worn cast iron surfaces, it has been indicated that there existed Mo compounds (MoO3, MoS2) and sulfide (FeS) on the worn surfaces in presence of MoDTC, whereas only sulfides were detected on the worn surfaces when lubricated with the fully formulated engine oil without addition of MoDTC. An attempted tribochemical modeling was elaborated by means of HSAB principle for describing the formation of boundary reacted films in case of formulation of MoDTC with the conventional multipurpose additive, Zn dialkyldithiophosphate (ZDTP).