Hierarchical CuCo-LDH/FeOCl nanocomposites for synergistic and stable superlubricity under elevated loads

A CuCo-LDH/FeOCl nanocomposite for macroscopic superlubricity is designed. • Stable macroscopic superlubricity is achieved under elevated loads (up to 75 N). • An ultralow friction coefficient ( ca. 0.0037) is realized in PEG200. Achieving stable superlubricity under elevated loads remains a significant challenge due to the fragility of conventional lubrication interfaces. Herein, a hierarchical CuCo layered double hydroxide/FeOCl nanocomposite is rationally designed via a microwave-assisted method to realize macroscopic superlubricity under elevated applied loads. The ultralow friction coefficient of ca . 0.0037 and the maintained superlubricity under loads up to 75 N may be attributed to the synergistic effects of the layered architecture, interlayer interactions and reactions, and tribochemical processes. Detailed characterization suggests that tribochemical evolution occurs during sliding, accompanied by possible Fe-O-M (M = Cu, Co) interfacial interactions, which may facilitate shear-induced structural evolution and interlayer sliding. Meanwhile, the synergistic effect between FeOCl and CuCo-LDH may contribute to the formation of a protective tribofilm at the friction interface. Repeated start-stop tests indicate that the real-time COF mainly fluctuates within 0.001–0.0075, maintaining stable superlubricity. This work provides new insights into the design of high-performance lubricating materials and offers a promising strategy for achieving stable superlubricity under elevated loads. Download: Download high-res image (202KB) Download: Download full-size image