In situ preparation of Cu-Mo-S nanoparticle additive with multi-functional tribological properties

Complex operating conditions pose greater challenges for lubricants, making the development of multi-functional additives a trend. This research introduces a multifunctional Cu-Mo-S nanoparticle (CMS) additive, synthesized using a unique one-pot in situ method. The CMS significantly improved the tribological performance and oxidation stability of base oils. Specifically, 0.5 wt% CMS manifested a remarkable reduction in the friction coefficient and wear volume of ester-based oils by 74.75% and 95.91%, accompanied by a noteworthy increase in the extreme pressure capabilities exceeding 50%, outperforming the individual copper nanoparticles, organic molybdenum, and their mixtures. The remarkable results are attributed to the distinctive structure of CMS, which decomposed during the friction process, forming a continuous friction film containing copper, molybdenum, and iron compounds.