Amphiphilic Zirconium Phosphate Nanoparticles as Tribo-Catalytic Additives of Multi-Performance Lubricants

Abstract

The advancement of electric vehicles demands lubricants with multifunction and performance. In this research, we investigated amphiphilic ZrP nanoparticles as lubricant additives. Experiments showed that the nanolubricant produced a tribofilm reduced the friction for 40% and wear 90%, while the electrical conductivity remained to be stable during tribotesting. Surface characterization of the tribofilm showed that there was a layered pyrophosphate on the wear track. The in situ impedance study about tribochemical kinetics revealed that the process in formation of a tribofilm involved simultaneous growth and wear. During growth, the coefficient of friction increased with continued formation of such film. During wear, the material removal rate was a function of friction, i.e., the higher the wear-rate, the higher the friction coefficient. The competing mechanisms of film growth and wear resulted in an electrically uniformed surface.