含硫硼酸酯与磷酸三甲酚酯复合添加剂在菜籽油中的协同效应

The Synergistic Effect between Synthetic S-containing Borate Ester and Tricresyl Phosphate in Rapeseed Oil

合成了 3种含硫硼酸酯 ,利用四球摩擦磨损试验机考察了含硫硼酸酯、磷酸三甲酚酯及其复合添加剂对菜籽油摩擦学性能的影响以及添加剂结构、组成与其摩擦学性能的关系 ,用 X射线光电子能谱仪和扫描电子显微镜观察分析了磨损表面的形貌和元素化学状态 .结果表明 :合成的含硫硼酸酯在一定浓度范围可以改善菜籽油的抗磨性能 ;所考察的添加剂在适当的添加量下均可提高菜籽油的承载能力和抗磨性能 ,但减摩效果不显著 ;含上述添加剂的菜籽油在摩擦过程中发生摩擦化学反应 ,生成由菜籽油甘油酯和添加剂摩擦化学反应产物组成的边界润滑膜 。

Three S containing borate esters (abridged as BS1, BS2 and BS3) were synthesized. The antiwear and friction reducing properties of BS2, commercial additive tricresyl phosphate (coded as TCP) and the mixture of BS2 and TCP of a mass fraction 1:1 as additives in rapeseed oil were examined with four ball machines. The relationship between additive structure, composition and tribological properties was explored, while the lubrication mechanisms of the additives investigated as well. Thus the worn surfaces of the steel ball lubricated with the additive containing rapeseed oil were analyzed by means of X ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It has been found that S containing borate esters as additives in rapeseed oil at proper concentrations are effective in improving the antiwear behavior and BS2 exhibits better antiwear ability than BS1 and BS3. All the additives BS2, TCP and BS2P can improve the load carrying capacity and antiwear ability of rapeseed oil within the tested concentration but are not always effective in improving the friction reducing behavior. The composite additive BS2P shows better tribological behavior than BS2 and TCP. This is attributed to the synergistic effect between BS2 and TCP. The XPS analytical results of the worn steel surfaces indicate that tribochemical reactions were involved for steel steel frictional pair lubricated with BS2P/RO, with the formation of a boundary lubricating and protecting film composed of triester of rapeseed oil and tribochemical reaction products of the lubricants. This contributes to improve the tribological properties of the rapeseed oil base stock.