Physicochemical and tribological properties of gemini-type halogen-free dicationic ionic liquids

• Published in: Friction Vol. 9; no. 2; pp. 344 - 355
• Main Authors: Yu, Qiangliang, Zhang, Chaoyang, Dong, Rui, Shi, Yijun, Wang, Yurong, Bai, Yanyan, Zhang, Jiaying, Cai, Meirong, Zhou, Feng, Liu, Weimin
• Format: Journal Article
• Language: English
• Published: Beijing Tsinghua University Press 01.04.2021; Springer Nature B.V; Lubricating Oil Key Laboratory of Petro China,Lanzhou Lubricating Oil Research&Development Institute of Petro China,Lanzhou730060,China%State Key Laboratory of Solid Lubrication,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000,China%State Key Laboratory of Solid Lubrication,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000,China; Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China%Division of Machine Elements,Lule?University of Technology,Lule?97187,Sweden; State Key Laboratory of Solid Lubrication,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000,China
• Subjects: Chains; Contact resistance; Corrosion and Coatings; Corrosion tests; dicationic ionic liquids (ILs); Electric contacts; Engineering; Friction; Friction reduction; halogen-free; Ionic liquids; Ions; lubricant; Lubricants; Machine Elements; Maskinelement; Mechanical Engineering; Mechanical properties; Nanotechnology; Photoelectrons; Physical Chemistry; Research Article; Stability analysis; Surfaces and Interfaces; Thin Films; tribofilm; Tribology; Ultrasonic testing; Wear; X ray photoelectron spectroscopy; dicationic ionic liquids (ILs); tribofilm; halogen-free; lubricant
• ISSN: 2223-7690; 2223-7704; 2223-7704
• DOI: 10.1007/s40544-019-0348-5

A series of new halogen-free dicationic ionic liquids (ILs) with different alkyl chain lengths were prepared, and the relationship between the alkyl chain length, physicochemical and tribological properties of ILs, and their role as neat lubricant for steel-steel friction pairs, was investigated. Evaluation of stability during hydrolysis and copper strip corrosion test results show that synthetic ILs are stable and not corrosive to metal contacts, due to the halogen-free anions. The friction and wear test results indicate that ILs with long alkyl chains have excellent friction-reducing and anti-wear properties, especially at high temperatures. Based on the surface three-dimensional (3D) profiles, electrical contact resistance, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and the X-ray photoelectron spectrometry (XPS) analysis of the worn surfaces of steel discs, we can conclude that the efficiency of ILs is due to the formation of high quality tribofilms that consist of both tribochemical reaction and ordered absorption films.