Insights into the tribological behavior of choline chloride—urea and choline chloride—thiourea deep eutectic solvents

Abstract Deep eutectic solvents (DESs) have been considered as novel and economic alternatives to traditional lubricants because of their similar physicochemical performance. In this study, choline chloride (ChCl) DESs were successfully synthesized via hydrogen-bonding networks urea thiourea the hydrogen bond donors (HBDs). The as-synthesized ChCl-urea ChCl-thiourea had excellent thermal stability displayed good lubrication between steel/steel tribo-pairs. friction coefficient wear rate DES 50.1% 80.6%, respectively, lower than those for GCr15/45 steel However, GCr15/Q45 steel, decreased by 85.0% in comparison DES. Under lubrication, tribo-chemical reaction film composed FeS formed at interfaces contributed low wear. under high von Mises stress, could not be stably retained serious was obtained through direct contact pairs. This illustrated that evolution responsible anti-friction anti-wear properties DESs.