Synthesizing basic lead (II) carbonate/graphene nanocomposite as a lubricating grease additive at elevated temperature

Graphene-based nano lubricant additives have attracted much attention due to their structure and exceptional physical properties. However, some issues still hinder graphene’s practical application for grease lubricants: graphene-based additives are difficult to disperse in grease, and lubrication failure is easy under extreme working conditions. In this study, basic lead (II) carbonate/graphene (Pb 3 (CO 3 ) 2 (OH) 2 #G) nano-composites are synthesized by a facile solution reaction method. To improve the dispersity, the Pb 3 (CO 3 ) 2 (OH) 2 #G is modified by a silane coupling agent (SCA) via the mechanochemical method (Pb 3 (CO 3 ) 2 (OH) 2 #G-SCA). The tribological properties of base greases can be significantly improved via adding a few of Pb 3 (CO 3 ) 2 (OH) 2 #G-SCA (0.5 wt.%). Especially, the COF and wear depth of greases could be reduced respectively by 30% and 60% at elevated temperature (150 °C). The grease with Pb 3 (CO 3 ) 2 (OH) 2 #G-SCA can still provide good lubrication properties at a higher temperature (175 °C). It is believed that the improved lubrication property with Pb 3 (CO 3 ) 2 (OH) 2 #G-SCA is due to the synergistic effect between graphene sheets and basic lead (II) carbonate nanoparticles. This work opens a good way to prepare graphene-based lubricant additives for high temperature applications.