Efficient and sustainable use of water-based lubricants is essential for energy efficiency.Therefore,the use of water-lubricated mechanical systems instead of conventional oil lubricants is extremely attractive from the viewpoint of resource conservation.In this study,water-soluble Cu nanoparticles of size approximately 3 nm were prepared at room temperature(around 25 °C) via in-situ surface modification.The tribological behavior of the as-synthesized Cu nanoparticles as an additive in distilled water was evaluated using a universal micro-tribotester.The results show that the as-synthesized Cu nanoparticles,as a water-based lubricant additive,can significantly improve the tribological properties of distilled water.In particular,the lowest friction coefficient of 0.06 was obtained via lubrication with a concentration of 0.6 wt% of Cu nanoparticles in distilled water,which is a reduction of 80.6% compared with that obtained via lubrication with distilled water alone.It is considered that some Cu nanoparticles entered the contact area of the friction pairs to form a complex lubricating film and prevent direct contact of the friction pairs.Furthermore,some Cu nanoparticles in the solution accelerate the heat transfer process,which also results in good tribological properties.
润滑油中抗氧剂含量决定着润滑油的剩余寿命,研究一种抗氧剂含量快速、简便的测量方法对于润滑油研究十分重要。研究线性扫描伏安法测定润滑油中抗氧剂含量的原理和方法,基于普林斯顿电化学工作站,探讨电解质溶液和扫描速率对测量体系中抗氧剂产生特征伏安峰的影响。结果表明,扫描速率为5 m V/s时,酚类和胺类抗氧剂在含有十二烷基磺酸钠、乙醇和硫酸的电解质溶液中都出现了特征伏安峰,并且抗氧剂的特征伏安峰高与抗氧剂浓度显示出正相关趋势,表明采用线性扫描伏安法测定润滑油中抗氧剂含量是可行的。线性扫描伏安法快速简便,可用于合成油和矿物油中抗氧剂含量的测定,该方法在合成油和矿物油中T501抗氧剂随着老化时间的延长而不断消耗的表征中取得良好效果。
