一种含硫氮硼酸酯润滑油添加剂的制备及其摩擦学性能

Preparation of Borate Ester Lubricating Oil Additive Containing Sulfur and Nitrogen and Evaluation of Its Tribological Properties

为了提高硼酸酯的摩擦学性能和水解稳定性,将黄原酸、二乙醇胺等官能团引入其分子结构中,合成了一种含硫氮硼酸酯润滑油添加剂(SNB)。采用红外光谱、元素分析对SNB的分子结构进行了表征,研究了其在基础油聚α-烯烃(PAO)中的溶解性和水解稳定性;用MQ-12-Ep型四球试验机考察了SNB在PAO中不同含量、不同载荷下的摩擦学性能,利用MicroXAM型三维轮廓仪、X射线光电子能谱仪(XPS)分析了4只钢球磨损的表面形态。结果表明,SNB具有良好的油溶性和水解稳定性,当其为1.0%(质量分数)时,钢球的磨斑直径(WSD)和摩擦系数分别比PAO降低43%和47%,PB值提高40%;SNB良好的抗磨、减摩及承载能力归因于其在摩擦过程中发生了摩擦化学反应,并形成了主要由B2O3,含氮化合物,FeSO4和FeS等组成的边界膜。

Borate ester was allowed to react with xanthic acid containing active S and diethanolamine containing active N generating S- and N-containing borate ester (denoted as SNB) . The chemical structure and elemental composition of as-prepared SNB were analyzed with an infrared spectrometer and an elemental analysis facility. Besides,the solubility and hydrolytic stability of SNB in poly-α-olefin (PAO) were determined,and its tribological properties in PAO base oil at different mass fractions and loads were evaluated with a four-ball friction and wear tester. In the meantime,the morphology of worn steel surfaces was measured with a three dimensional optical profiler,and the chemical states of some typical elements on worn steel surfaces were analyzed with an X-ray photoelectron spectroscope. Results showed that the SNB had good solubility and hydrolytic stability in PAO base oil. Besides,when SNB was added into PAO base oil at a mass fraction of 1. 0%,it was able to reduce the wear scar diameter of steel ball and friction coefficient by 43% and 47%,respectively,and increase the P B value by 40%,showing good antiwear,friction-reducing,and extreme pressure properties. SNB additive underwent tribochemical reaction during sliding process thereby forming a boundary lubricating film consisting of B 2 O 3 ,N-containing organic compound,FeSO 4 and FeS on worn steel surfaces.