Synthesis of phosphorus-free thiazole-based organomolybdate as a high-performance lubricant additive

Abstract

In this study, a novel phosphorus-free organic molybdate (BMVMo) was synthesized by a simple method and its tribological performance as an additive in lithium grease was evaluated. Tribological tests demonstrated that the combination of BMVMo and zinc dialkyl dithiophosphate (ZDDP) exhibited remarkable synergistic friction-reducing and anti-wear properties. The incorporation of 1% BMVMo and 1% ZDDP into lithium grease resulted in a reduction of the average coefficient of friction (ACOF) and wear volume by 43.97% and 77.05%, respectively. Further analysis of the friction surface led to the proposal of a lubrication mechanism comprising physical adsorption and a complex tribochemical reaction, resulting in the formation of a protective film. The formation of a continuous and stable tribofilm of 20–40 nm effectively reduced shear stress, thus providing optimal reduction of friction and anti-wear effects.