MoS₂/WS₂ Quantum Dots as High‐Performance Lubricant Additive in Polyalkylene Glycol for Steel/Steel Contact at Elevated Temperature

Abstract

Abstract Herein, molybdenum disulfide (MoS 2 ) and tungsten disulfide (WS 2 ) quantum dots (QDs) are prepared by a facile and green technique, and characterized by microscopy and spectroscopy. The resulting products display exceptional stability in polyalkylene glycol (PAG) base oil, and are used for the first time as friction reducing and antiwear additives in PAG for steel/steel contact. Tribological measurements indicate that the stable dispersion consisting of PAG mixed with MoS 2 /WS 2 QDs exhibits significant tribological properties compared with pure PAG and PAG containing MoS 2 /WS 2 QDs nanosheets under different loads at elevated temperatures. The excellent tribological behaviors of MoS 2 /WS 2 QDs are attributed to the formation of a boundary lubrication film, which can be generated not only by the physical entrapment of MoS 2 /WS 2 QDs at the ball‐disk contact surfaces, but also by tribochemical reaction between MoS 2 /WS 2 and the iron atoms/iron oxide species.