Origin of the tribofilm from MoS_(2) nanoparticle oil additives: Dependence of oil film thickness on particle aggregation in rolling point contact

作     者：Hongxing WU Liping WANG Guangneng DONG Hongxing WU;Liping WANG;Guangneng DONG

作者机构：State Key Laboratory of Solidification ProcessingCenter of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’an 710072China Petro China Lanzhou Lubricating Oil R&D InstituteLanzhou 730060China Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing SystemXi'an Jiaotong UniversityXi'an 710049China 

出 版 物：《Friction》 (摩擦（英文版）)

年 卷 期：2021年第9卷第6期

页      面：1436-1449页

核心收录：

学科分类：07[理学] 070205[理学-凝聚态物理] 08[工学] 080203[工学-机械设计及理论] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 0702[理学-物理学] 

基　　金：This work was supported by the Fundamental Research Funds for the Central Universities(31020195C001,3102019QD0413,3102019ZD0403) The suggestions from Q.Jane Wang at Northwestern University are appreciated.Hongxing Wu also acknowledges the scholarship support from the China Scholarship Council(CSC,No.201606280181) 

主　　题：nanoparticle lubrication oil film thickness flow pattern particle aggregation 

摘      要：The lubrication effectiveness of MoS_(2) nanoparticles as an oil additive remains unclear,restricting its application in industry to reduce *** goal of this work was to explore the lubrication mechanism of MoS_(2) nanoparticles as an oil *** this study,the oil film thickness behaviors of MoS_(2) nanoparticles in poly-alpha olefin(PAO4)base oil,PAO4 with 3 wt%dispersant(polyisobutyleneamine succinimide,PIBS),and 0W20 engine oil were investigated using an elastohydrodynamic lubrication(EHL)testing *** the EHL tests,the flow patterns around the contact area and the tribofilm covering rate on contact area were studied using optical microscopy to understand the lubrication *** results indicate that both the dispersant and nanoparticle aggregation significantly affected the oil film *** expected oil film thickness increase in the case of 0.1 wt%MoS_(2) in PAO4 base oil was obtained,with an increase from 30 to 60 nm over 15 min at a velocity of 50 mm/*** pattern analysis revealed the formation of particle aggregation on the rolling path when lubricated with 0.1 wt%MoS_(2),which is associated with a tribofilm coverage rate of 41.5%on the contact ***,an oil film thickness increase and particle aggregation were not observed during the tests with 0.1 wt%MoS_(2) blended with 3 wt%PIBS as the dispersant in PAO4 base oil,and for 0.75 wt%MoS_(2) in 0W20 engine *** results suggest that nanoparticles responsible for tribofilm formation originated from aggregates,but not the well-dispersed nanoparticles in point *** understanding should aid the advancement of novel lubricant additive design.