The Effect of Additive Chemical Structure on the Tribofilms Derived from Varying Molybdenum-Sulfur Chemistries
The Effect of Additive Chemical Structure on the Tribofilms Derived from Varying Molybdenum-Sulfur Chemistries
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DOI：
10.1007/s11249-021-01493-z
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发表时间：
2021-09
影响因子：
3.2
通讯作者：
Aaron L. Barnes;A. Morina;Rhiann E. Andrew;A. Neville
中科院分区：
文献类型：
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作者：
Aaron L. Barnes;A. Morina;Rhiann E. Andrew;A. Neville
二硫化钼(MoS_2)是一种由油溶性润滑油添加剂在表面形成的有效的摩擦改进剂。可以使用不同的添加剂化学反应在表面上形成MoS2。研究了三种不同钼添加剂(MoDTC二聚体、MoDTC三聚体和钼酸酯)在添加剂单一配方和全配方体系中形成的摩擦膜。用拉曼光谱、XPS和FIB-TEM对所得摩擦膜进行了表征。与其他添加剂相比，钼酸盐酯表面MoS2的分布更为稀疏。拉曼光谱没有观察到晶态钼氧化物的存在，但XPS分析推测了它们的存在。XPS分析表明，每个添加剂的Mo氧化态分布非常相似，因此所有添加剂形成的薄膜的化学性质可能是相似的。观察到每种添加剂摩擦膜的拉曼峰和过硫化物XPS峰都有与无定形MoS3有关的MoS3振动，因此对于所有添加剂来说，这种物种都是共同的摩擦分解产物。MoDTC三聚体由于其结构与配位聚合物MoS3相似，更能在接触表面产生这种无定形物种。
Molybdenum disulfide (MoS2) is an effective friction modifier that can be formed on surfaces from oil-soluble lubricant additives. Different additive chemistries can be used to form MoS2on a surface. The tribofilms formed from three different molybdenum additives (MoDTC Dimer, MoDTC Trimer, and molybdate ester) were studied in additive monoblends and fully formulated systems. The resulting tribofilms were then characterized by Raman spectroscopic spatial mapping, XPS, and FIB-TEM. The distribution of MoS2on the surface was much more sparse for the molybdate ester than the other additives. No crystalline molybdenum oxides were observed by Raman spectroscopy, but their presence was inferred from XPS analysis. XPS analysis showed very similar distributions of Mo oxidation states from each additive, such that the chemical nature of the films formed from all of the additives is likely similar. Each of the additive tribofilms was observed to have MoS3vibrations in Raman and persulfide XPS peaks associated with amorphous MoS3, as such this species is presented as a common frictional decomposition product for all the additives. The MoDTC trimer is more able to produce this amorphous species on the contacting surfaces due to its structural similarities to the co-ordination polymer MoS3.Graphical Abstract