Tribology study of lanthanum-treated graphene oxide thin film on silicon substrate

Abstract

Low friction coefficient and wear rate of components are crucial for nano-electromechanical-systems (NEMS). Herein, we have prepared carboxylated graphene oxide (GO) complexes with lanthanum on silicon substrate in order to form a two-dimensional self-assembled monolayer using 3-aminopropyl triethoxysilane (APTES) silane coupling agent (marked as APTES–GO–La). The chemical compositions, microstructures, and surface morphologies of samples were analysed by X-ray photoelectron spectroscopy (XPS), water contact angle (WCA), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The tribology behaviour of the as-prepared thin films was tested by UMT-2 tribometer. Results show that GO sheets were successfully grafted on a silicon substrate and lanthanum was attached to a GO sheet by coordination reaction. The obtained APTES–GO–La film has a low friction coefficient and good wear-resistant properties. Its remarkable tribological properties are attributed to the strong bond of the film to the substrate and the special characteristics of the rare earth (RE) element and GO sheet. This film has potential applications in NEMS.