A novel imidazolium salt with antioxidation and anticorrosion dual functionalities as the additive in poly(ethylene glycol) for steel/steel contacts

Imidazolium ionic liquids (ILs) containing sterically hindered phenol and benzotriazole groups were synthesized and evaluated as combined antiwear (AW), antioxidation, and anticorrosion additive in poly(ethylene glycol) (PEG) for steel/steel contacts at room temperature and 100 °C. The physical properties of the synthetic ILs and PEG with the additive were measured. The antioxidation and anticorrosion properties of the synthetic ILs were assessed via the thermal analysis, an accelerated corrosion test and copper strip corrosion test, which showed the excellent antioxidation and anticorrosion properties in comparison with the pure PEG and the selected conventional ILs having no functional groups. Tribological results indicated that these ILs as the additives could effectively reduce friction and wear of sliding pairs in PEG. The tribological properties were generally better than the common IL (L-P106) in PEG. The wear mechanisms are tentatively discussed according to the morphology observation of worn surfaces of steel discs by scanning electron microscope (SEM) and the surface composition analysis was obtained by X-ray photoelectron spectroscopy (XPS).