Guo Jie, Cheng Jun, Tan Hui, Sun Qichun, Yang Jun, Liu Weimin
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
Nanoscale. 2020 Apr 28;12(16):9208-9218. doi: 10.1039/c9nr10621a. Epub 2020 Apr 20.
The development of a high-performance nanoparticle (NP) additive for lubricating oil is a research hotspot for the tribology and engineering areas. In this study, the concept of a novel liquid nano-additive has been proposed based on the emergence of Ga-based liquid metals (GLMs), which display excellent extreme-pressure and high-temperature lubricity. Herein, the liquid NPs (designated as GLM-NP/C12) were prepared from a GLM droplet through the ultrasonic method, modified with 1-dodecanethiol, and are mainly distributed at 286 ± 21 nm. They have a core-shell structure with liquid-state GLM on the inside, and gallium oxide and a self-assembled alkylthiolate monolayer on the outside. In terms of the tribological performance, GLM-NP/C12s have a wonderful dispersion-stability in PAO10 oil, and provide excellent anti-adhesion, friction-reducing, and wear-resistance properties. When the additive concentration was 0.17 wt% in PAO10, the friction coefficient was reduced by 39% and the wear rate was reduced by 93% compared to those lubricated by the neat PAO10. This kind of liquid nano-additive has the advantages of easy preparation, internal composition regulation and recyclability, compared to conventional solid NPs. In addition, the liquid NPs were readily introduced into the frictional interfaces. More generally, the optimal additive concentration of the liquid NPs was much lower than that of the solid NPs. This observation has important implications for understanding the differences of the lubrication mechanisms between the solid and liquid nano-additives, and may provide a new design method and strategy of nano-additives for lubricating oil.
开发一种用于润滑油的高性能纳米颗粒（NP）添加剂是摩擦学和工程领域的研究热点。在本研究中，基于镓基液态金属（GLMs）的出现，提出了一种新型液体纳米添加剂的概念，镓基液态金属具有优异的极压和高温润滑性。在此，通过超声法由GLM液滴制备了液态NP（命名为GLM-NP/C12），并用1-十二烷硫醇进行了改性，其主要粒径分布在286±21nm。它们具有核壳结构，内部为液态GLM，外部为氧化镓和自组装的烷基硫醇盐单层。在摩擦学性能方面，GLM-NP/C12在PAO10油中具有出色的分散稳定性，并具有优异的抗粘附、减摩和耐磨性能。当PAO10中添加剂浓度为0.17wt%时，与纯PAO10润滑相比，摩擦系数降低了39%，磨损率降低了93%。与传统固体NP相比，这种液体纳米添加剂具有易于制备、内部成分可调控和可回收的优点。此外，液态NP很容易引入到摩擦界面中。更普遍地说，液态NP的最佳添加剂浓度远低于固体NP。这一观察结果对于理解固体和液体纳米添加剂润滑机制的差异具有重要意义，并可能为润滑油纳米添加剂提供一种新的设计方法和策略。
