基于分子动力学的富勒烯润滑油摩擦学特性分析

为探究不同富勒烯(C₇₀和C₆₀)作为润滑油添加剂的摩擦学特性及其减摩抗磨机制。采用球/盘往复式摩擦磨损试验机考察了C₇₀和C₆₀在石蜡(LP)基础油中的摩擦学性能；采用激光扫描显微镜(LSM)、扫描电子显微镜(SEM)、原子力显微镜(AFM)、拉曼光谱(Raman)和光电子能谱(XPS)分析了磨痕的表面形貌及组成；基于分子动力学模拟分析了富勒烯与摩擦副间的范德华能以及富勒烯分子的径向分布函数(RDF)。结果表明：C₇₀和C₆₀润滑下摩擦系数降低，且磨损率分别降低26.92%和 34.56%，富勒烯可改善石蜡的摩擦学性能，减少磨粒磨损，并于摩擦表面生成由富勒烯参与的摩擦反应膜；同时，富勒烯与摩擦副基体间的范德华能较高，优先吸附摩擦表面；径向分布函数表明，富勒烯表面发生了油分子的聚集，有利于形成油膜，从而进一步改善润滑。

Analysis of Tribological Performance of Lubricating Oil With Fullerene by Molecular Dynamics Simulations

In order to explore the tribological behaviour and the lubrication mechanism of different kinds of fullerenes, the tribological behaviour of C₇₀ and C₆₀ in base oil (LP) was evaluated by using ball on-disk reciprocating tribometer. The surface morphology and composition of wear scars were analyzed by laser scanning microscope (LSM), scanning electron microscope (SEM), atomic force microscope (AFM), Raman and X-ray photoelectron spectroscopy (XPS). The van der Waals energies between fullerenes and rubbing substrate surface, as with the radial distribution function (RDF) of C₆₀ or C₇₀ molecules were analyzed based on molecular dynamics simulations. The results show that the friction coefficients of lubricates with C₇₀ and C₆₀ decrease, and the wear rates decrease by 26.92% and 34.56%, respectively. In short, fullerene improves the tribological properties of LP and reduce abrasive wear, which are because of the formation of friction reaction film on surface. The van der Waals energy between fullerene and the rubbing surface is larger and fullerenes are prior to adsorption on the friction surface. The radial distribution function indicates that oil molecules gather on the surface of fullerene, which is beneficial to form the oil film.