Bin Wang,Kai Gao,Kai Wang,Yujie Wang,Qiuying Chang,He Yang
The tribological behavior of carboxylic acids, especially oleic acid, in boundary lubrication conditions is a subject of interest. This study presents the results of four-ball tribological tests conducted under varying contact pressures and sliding speeds. The findings reveal a critical turning speed within a confined zone, which causes a significant change in the frictional performances of oleic acid, leading to the formation of an ultralow wear tribofilm. This tribofilm, predominantly composed of oxyhydrogen compounds and hydrocarbons with more than five carbon atoms, is generated by the molecular action of oleic acid. Reactive nonequilibrium molecular dynamics simulations demonstrate that the shear speed-dependent decomposition modes of oleic acid and the transformation of the lubrication slip interface are the fundamental processes underlying the formation of this ultralow-wear boundary tribofilm.
This study investigated the frictional properties of HPMC under different load and concentration conditions through friction experiments and surface characterization. The study aimed to explore and reveal the influence of load and concentration on the frictional properties of HPMC, as well as its anti−wear mechanism. The results of the study indicated that under the same solution concentration, the effect of load on the friction coefficient of HPMC was not significant. Specifically, for samples with low concentration (C−0.2), the wear ratio of HPMC under a 4 N load (1.01 × 10−11mm3·N−1·m−1) was significantly lower than the wear ratio under a 2 N load (1.71 × 10−10mm3·N−1·m−1). The orientation−driven formation of graphite−like carbon nanosheets, initiated by the decomposition of HPMC short chains, created a tribofilm−containing organic−chain mixed nanosheet on the sliding contact surface, which prevented direct contact between the upper and lower friction pairs. This achieved the anti−wear mechanism of two−body wear (tribo−film of an mDLC−coated ball and tribo−film of a GLC−coated Si wafer), ultimately leading to a state of ultra−low wear at the interface. The excellent anti−wear performance of HPMC suggests its potential as a candidate for the next generation of environmentally friendly bio−based solid lubricants.
危险品化学品经营许可证（带存储）