Effect of interfacial interaction between Nano-SiO2 and NBR on tribological properties of NBR water-lubricated bearings

This paper investigates how nano-SiO2 interacts with NBR to affect the tribological properties of water-lubricated NBR-based composites using the Rtec friction and wear tester and the molecular dynamics simulation method. The surface-modified nano-SiO2 (SiO2(TESPT)) particles were prepared by modifying the hydroxyl groups on the surface of nano-SiO2 with Silicon 69 (TESPT), and cast copper alloy (ZCuSn10Zn2) was used as the counterface material in the friction test and wear test. The results showed that different interfacial interplay between nano-SiO2 and NBR makes for distinct wear mechanisms of NBR-based composites. With weak interface bonding between nano-SiO2 and NBR, NBR/SiO2 can easily get worn as nano-SiO2 particles detach from the matrix during the wear process, leaving pits and cracks on the worn surface. Instead, SiO2(TESPT) has stronger interface bonding with the matrix, which can prevent the detachment of SiO2(TESPT) restrict the movement of molecular chains in NBR, and reduce the temperature peak of the friction pair. SiO2(TESPT) exerts a dual influence on the tribological properties of NBR: while significantly improving the wear resistance of NBR, it can also notably increase the friction coefficient of the composite.