Tribological behavior of two novel choline acetate-based deep eutectic solvents

• DESs are easy to synthetize and generally cheaper than ILs. • Acetate-based DESs are non-corrosive. • Choline acetate-based DES used as a lubricant reduce friction and wear. The present work evaluates the tribological behaviour of two novel and eco-friendly Deep Eutectic Solvents based on choline acetate and compares their performance with that of two other lubricants used as reference: a glyceline and a reline that have been the subject of extensive research in tribology. For all of them, the coefficient of friction was determined under different configurations and test conditions, and the wear volume was quantified using a confocal microscope. In addition, these lubricants were subjected to different analyses for physicochemical characterization. These studied Deep Eutectic Solvents were thermally stable and showed no corrosive action. In addition, the choline acetate urea Deep Eutectic Solvent managed to drastically reduce both friction and wear compared to the values determined for other lubricants used as reference. Surface analysis of the wear tracks suggests that these results are related to the interaction of the lubricants with the steel surfaces.