Effects of hBN and CaCO3 Nanoparticles on Tribological and Vibration Properties of Polyurea Grease on Rolling Bearing

The influences of Hexagonal boron nitride (hBN) and Calcium carbonate (CaCO3) nanoparticles on tribological and bearing vibration properties of polyurea grease (PG) were investigated. The microstructure, friction coefficient, wear morphology, and bearing vibration test of five components of greases were conducted. The results showed that the addition of 1 wt% hBN, playing the role of isolation protection and nano-abrasive, could improve the wear and vibration reduction performance of PG. However, the addition of CaCO3 nanoparticles at the same time, playing the role of deposition and recovery, could further improve the tribological and vibration reduction performance of PG, which was attributed to the synergistic effect of CaCO3 and hBN particles. The findings revealed that PG with the addition of 1 wt% hBN + 5 wt% CaCO3 nanoparticles had the greatest tribological and vibration suppression performance, which is due to the synergistic effect of hBN and CaCO3 nanoparticles. Additionally, the wettability tests showed that the addition of hBN and CaCO3 nanoparticles could significantly increase the flow of base oil on the PG soap fibers, resulting in the most effective bearing vibration suppression.