Both Nano-SiO2 (Silicon dioxide nanoparticles) additive concentration and axial load have profound effects on the friction and wear of Tungsten Carbide bearings in the drilling fluid environment. However, the coordinated role of them remains unknown. In this work, the effects of Nano-SiO2 concentrations and axial loads on the tribological behavior of bearing materials were investigated simultaneously. Results show that the water-based drilling fluid containing Nano-SiO2 exhibits more excellent lubrication properties under 200 N as compared with 70 N, and the optimal concentration of Nano-SiO2 additive is 1.0 wt% under all loads. High axial loads are conducive to improve the lubrication performance, and the lubrication mechanisms of Nano-SiO2 under different loads in water-based drilling fluid are the multitudinousness of synergistic effects, including rolling bearing, polishing, shielding, and self-healing effect, which all manifested there is an remarkable load dependence of Nano-SiO2 particles.
