油溶性有机钼添加剂的摩擦学性能及其摩擦化学作用机制

Tribological Properties and Tribochemical Mechanisms of Oil-Soluble Organo-Molybdenum Additives

采用四球摩擦磨损试验机考察了2种油溶性有机钼添加剂2 乙基己基 二硫代磷酸氧钼(MoDDP)和硫化 二异丙基 二硫代磷酸钼(MoDTP)的摩擦学性能及其复配体系的抗磨减摩性能,采用扫描电子显微镜和X射线光电子能谱仪分析了磨斑表面形貌和表面膜元素组成,探讨了有机钼添加剂的摩擦化学作用机制.结果表明,有机钼添加剂MoDDP和MoDTP均具有优异的摩擦学性能,其复配体系呈现协同抗磨减摩效应,这是由于有机钼添加剂在摩擦副表面形成由FeS、MoS2及MoO2组成的化学反应膜和由含磷化合物组成的沉积膜所致.

A four-ball machine was performed to investigate the tribological performances of organo-Mo coumpounds (oxymolybdenum dithiophosphate and molybdenum dithiophosphate, coded as MoDDP and MoDTP, respectively) as additives in liquid paraffin. The synergetic friction-reducing and antiwear function of the two additives was also examined on the same test rig. The morphologies of the worn steel surfaces and the elemental distributions thereon under the lubrication of liquid paraffin and liquid paraffin containing different additives were observed and determined by means of scanning electron microscopy and energy dispersive spectrometry. The chemical states of some typical elements on the worn steel surface were analyzed on an X-ray photoelectron spectroscope. It was found that MoDDP and MoDTP as additives in liquid paraffin had good anti-wear and friction-reduction properties to the steel-on-steel system, which was attributed to the formation of a reaction film composed of MoS_2, FeS, and MoO_2, by way of the tribochemical reaction of the additives, and a deposited film composed of phosphate, on the worn steel surface. Moreover, the two additives had synergistic friction-reducing and antiwear effect, which was closely related to the chemical states of S on the worn steel surface.