Six used diesel engine oils from RFWT engine test were studied on changes in physical and chemical properties and were characterized by 31 P NMR. The ZDDP degradation was investigated by NMR spectroscopy and the depth etchings on the surface of RFWT test pieces were analyzed by X- ray photoelectron spectroscopy (XPS ). The results showed that the available phosphorus from bZDDP,nZDDP,and dithiophosphates,the decomposition product in early stage is the key effective an-ti-wear component. The lower the ratio of effective phosphorus to intermediate phosphorus,the lower the wear is. XPS surface analysis revealed a thicker anti-wear film on surface of lower wear test part by ZDDP and its degradation products serves as anti-wear protection. The film contains phosphate,sulfide and sulphate.%对6种柴油机油在滚轮从动件(RFWT)发动机试验后的旧油进行了理化分析、核磁共振磷谱(31 P NMR)分析,对RFWT试验件磨斑表面进行了X射线光电子能谱(XPS)深度刻蚀分析.结果表明:碱性ZDDP、中性ZDDP及其初期降解产物二硫代磷酸酯构成的有效磷是抗磨的主要组分,有效磷转化为中间磷的比例越少,磨损越低;ZDDP及其降解产物在低磨损试验件表面形成了较厚的含有硫化物、硫酸盐、磷酸盐等化合物的保护膜,起到了抗磨作用.
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