Tribological behavior and lubrication mechanism of nano g-C3N4 lubricant additive in paraffin oil on bearing steel disk

Purpose - Nano graphitic-carbon nitride (g-C3N4) is an emerging lubrication technology with excellent performance and significant potential for future applications. This study aims to investigate the effect of nano g-C3N4 as a lubricant additive on the wear performance of bearing steel disk. Design/methodology/approach - Various mass fractions of g-C3N4 were introduced into the base oil. Combining tribological testing, rheological testing and surface analysis methods, the anti-wear properties and lubrication mechanisms were analyzed. Findings - Transmission electron microscopy images revealed that the size of the nanoparticles of g-C3N4 ranges from 10 to 100 nm. Phase analysis of the g-C3N4 sample was conducted using X-ray diffraction. Further, 1.0% mass fraction of g-C3N4 in the base oil provides excellent anti-wear and friction-reducing performance. Compared to the base oil alone, it reduces the average friction coefficient by 63.8% and decreases the wear rate by 43.1%, significantly reducing the depth and width of the wear scar. Energy-dispersive X-ray spectroscopy and scanning electron microscope analysis revealed that the oil sample containing nano g-C3N4 can form a lubricating film on the sliding surface of bearing steel after wear, which enhances the lubricating properties of the base oil. Originality/value - The synergistic effect of the base oil and nanoparticles reduces friction and wear and is expected to extend the service life of bearing steel. These findings suggest that incorporating nano g-C3N4 as a lubricant additive offers significant potential for improving the performance of mechanical components. Peer review - The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2024-0456/