Ionic liquids as boundary additives in water-based and PAO lubricants  

作　　者：Wahyu WIJANARKO Hamid KHANMOHAMMADI Nuria ESPALLARGAS 

机构地区：[1]Norwegian Tribology Center,Department of Mechanical and Industrial Engineering,Norwegian University of Science and Technology(NTNU),Trondheim 7491,Norway [2]Department of Mechanical Engineering,Sepuluh Nopember Institute of Technology(ITS),Surabaya 6011,Indonesia

出　　处：《Friction》2022年第9期1405-1423,共19页摩擦（英文版）

基　　金：The authors would like to acknowledge the financial support from Indonesia Endowment Fund for Education(LPDP),M-ERA;NET GreenCOAT project with Project Number 4153,and the Norwegian Microand Nano-fabrication facility,NorFab,for providing the characterization facilities.

摘　　要：Ionic liquids have been widely discussed as potential lubricants,however,their properties make them also very good potential candidates as lubricant additives(e.g.,friction modifiers and anti-wear).In this work,the tribological study of two ionic liquids(tributylmethylphosphonium dimethylphosphate(PP),and 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate(BMP))as lubricant additives has been performed on stainless steel(AISI 316L)exposed to polar(water-glycol)and non-polar(polyalphaolefin)based lubricants under boundary lubricating conditions.The performance of these ionic liquids as lubricant additives has been compared to a classical organic friction modifier(dodecanoic acid(C12)).The water–glycol lubricant formulated with the two ionic liquids showed friction values higher than the same base lubricant formulated with dodecanoic acid,however,opposite results were observed for polyalphaolefin(PAO).A detailed surface chemical analysis using X-ray photoelectron spectroscopy(XPS)revealed differences in the passive/tribofilm thickness and chemical composition of the stainless steel surface tested in all lubricants.In the case of the polar lubricant additivated with ionic liquids,the tribochemical reaction accompanied by a tribocorrosion process led to the formation of an unstable passive/tribofilm resulting in high friction and wear.However,in the absence of tribocorrosion process(polyalphaolefin base lubricant),the tribochemical reaction led to the formation of a stable passive/tribofilm resulting in low friction and wear.A detailed surface and subsurface investigation of the microstructure using scanning electron microscopy equipped with a focused ion beam(SEM-FIB)showed that high wear rates resulted in thicker recrystallization region under the wear track surface.Among all lubricant additives tested in this work,BMP in non-polar lubricant media showed the best tribological performance.

关 键 词：water lubricant polyalphaolefin(PAO) ionic liquids TRIBOCHEMISTRY TRIBOCORROSION TRIBOFILM 

分 类 号：TH117.22[机械工程—机械设计及理论]