Core-rim structured MXene@SiO₂ composites as oil-based additives for enhanced tribological properties

Herein, we have prepared SiO₂ particles uploaded MXene nanosheets via in-situ hydrolysis of tetraetholothosilicate. Due to the large number of groups at the edges of MXene, SiO₂ grows at the edges first, forming MXene@SiO₂ composites with a unique core-rim structure. The tribological properties of MXene@SiO₂ as lubricating additive in 500 SN are evaluated by SRV-5. The results show that MXene@SiO₂ can reduce the friction coefficient of 500 SN from 0.572 to 0.108, the wear volume is reduced by 73.7%, and the load capacity is increased to 800 N. The superior lubricity of MXene@SiO₂ is attributed to the synergistic effect of MXene and SiO₂. The rolling friction caused by SiO₂ not only improves the bearing capacity but also increases the interlayer distance of MXene, avoiding accumulation and making it more prone to interlayer slip. MXene@SiO₂ is adsorbed on the friction interface to form a physical adsorption film and isolate the friction pair. In addition, the high temperature and high load induce the tribochemical reaction and form a chemical protection film during in the friction process. Ultimately, the presence of these protective films results in MXene@SiO₂ having good lubricating properties.