Enhancement of Triboactivity of Nanolamellar Graphitic-C3N4 by N-Doped ZnO Nanorods

Low-Temperature-Graphitized and Interpenetrating Network C/Fe3O4 Magnetic Nanocomposites with Enhanced Tribological Properties under High Temperature

Although the core-shell structure magnetic nanocomposites have been widely used as lubricant additives, their tribological properties are still poor under high temperature and high load. Herein, the graphitized C/Fe3O4 magnetic nanocomposites (g-C/Fe3O4) with an interpenetrating network structure were successfully fabricated by an in situ hydrothermal carbonization method combined with a subsequent ball milling process at room temperature. The results showed that the ball milling process not only promoted the transformation of graphitized carbon but also effectively eliminated the interfacial effect between carbon and Fe3O4. Moreover, the g-C/Fe3O4 used as a lubricant additive in rapeseed oil exhibited excellent tribological properties and high thermo-stability under 155 °C and 980 N, with the friction coefficient reduced by 32.8% compared to the independent Fe3O4. The enhanced tribological performance of g-C/Fe3O4 could be attributed to the graphitized carbon and its interpenetrating network structure under low load force (392 N), while under high load force (980 N), it could be ascribed to the synergistic effect between the graphitized carbon and magnetic Fe3O4 nanoparticles. This work not only offers a method for the synthesis of nanocomposite lubricant additives but also shows great potential in practical applications for high-temperature tribology.

Reinforcement of nanoporous lanthanum-doped zinc borate by vanadium selenide nanosheets for improved tribological activity

Nanoporous zinc borate (ZB) and 10% lanthanum-doped porous zinc borate (LZB) were synthesized to explore the role of porosity and doping in zinc borate during lubrication. HR-SEM, TEM, and HR-TEM authenticated nanoporous structures. The tribological properties of their blends with paraffin oil (PO) were compared by employing ASTM D4172 and ASTM D5183 norms on a four-ball tester. Vanadium selenide nanosheets (VSe₂) were used to reinforce the structure of LZB for further advancement of the tribological properties. The superiority of the LZB/VSe₂ over LZB and VSe₂ nanosheets could be adjudged by tribological data. The porosity and lanthanum doping have yielded commendable tribological activity. The VSe₂ nanosheets have strengthened the LZB matrix. The other constituent oxides of tribofilm from the LZB matrix, based on EDX analysis and XPS studies of the worn surface, ZnO, B₂O₃, La₂O₃, and V₂O₅, have abetted lubrication. The AFM and SEM investigations of wear track corroborated the tribological results.

Successful reinforcement of nanoporous lanthanum-doped zinc borate by vanadium selenide nanosheets and their utilization in Tribology has been described.