LAUSR

Abstract This study systematically investigated the physicochemical characteristics of hexagonal boron nitride (h-BN) nanoparticles dispersed in polyalphaolefin 6 (PAO6) from a molecular level to explore the thermal stability of nano-lubricants. The nanoparticles were characterized via transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and energy-dispersive spectrometry (EDS) to analyze the chemical bonds, element distribution, and impurity. We not only theoretically reveal the rheological behavior of nano-lubricants but also propose precise models to predict the viscosity. Moreover, this study comprehensively analyzed the thermal stability of nano-lubricants under different gas environments through thermogravimetric analysis and revealed that the nanofluid thermal stability was improved owing to the small-size effect. The results show that the thermal conductivity of the nano-lubricants was significantly higher than that of PAO6. Finally, the mechanism of thermal property enhancement by the h-BN nanoparticles is revealed.