TY - JOUR AB - Purpose– The purpose of this paper is to design the crown‐type phosphate ionic liquid additive which can dissolve in poly(ethylene glycol) (shortened to PEG) completely, and evaluate the tribological properties as additive in PEG for steel/steel contacts.Design/methodology/approach– To improve the solubility and the tribological performance of ionic liquid additive in PEG, the crown‐type phosphate ionic liquid additive was prepared. The tribological properties of the crown‐type phosphate ionic liquid additive in PEG were evaluated at different concentrations and rubbing frequencies on an Optimol SRV oscillating friction and wear tester. The morphology and chemical compounds of the wear scars were analyzed by scanning electron microscope (SEM) and X‐ray photoelectron spectroscopy (XPS).Findings– The experimental results show that the crown‐type phosphate ionic liquid additive applied in based oil exhibits better tribological properties for steel/steel contacts at different loads, concentrations and rubbing frequencies. It could improve the anti‐wear ability and reduce the friction coefficients as the increased concentration. By the SEM and XPS analysis, it is found that there were the effective boundary lubricant films in the worn surface. The boundary films were composed of various tribochemical products, ferric oxide, ferric phosphate and pyrophosphate, together with the absorbed films.Originality/value– Compared with the poor miscibility of some ionic liquid in PEG, the crown‐type phosphate ionic liquid additive can dissolve in PEG perfectly. It can improve the anti‐wear ability and reduce the friction coefficient of PEG at different concentrations and rubbing frequencies. VL - 65 IS - 3 SN - 0036-8792 DO - 10.1108/00368791311311204 UR - https://doi.org/10.1108/00368791311311204 AU - Jiang Dong AU - Hu Litian AU - Feng Dapeng PY - 2013 Y1 - 2013/01/01 TI - Tribological properties of crown‐type phosphate ionic liquid as additive in poly(ethylene glycol) for steel/steel contacts T2 - Industrial Lubrication and Tribology PB - Emerald Group Publishing Limited SP - 202 EP - 208 Y2 - 2024/04/24 ER -