Ultralow friction of graphene-coated silica nanoparticle film

Abstract

Reductions in friction and wear are widely sought to promote energy-saving and reliability in ubiquitous moving machine components. In this work, we demonstrate ultralow friction of graphene-coated silica nanoparticle films on diamond (111) surfaces by performing molecular dynamics simulations. Coated nanoparticles are prepared by enclosing 2.7 nm sized silica nanoparticles in C720 fullerene cages, which are used to construct a monolayer film with the face-centered-cubic (111) structure. Results indicate an ultralow friction coefficient, μ ∼ 0.07, for loads up to 18 GPa. The ultralow friction and high compressive strength are attributed to the coated structure that synergizes the outstanding low friction coefficient of C720 fullerenes with the nanobearing capability of silica nanoparticles. The realization of coated nanoparticles film-based ultralow friction has the potential to enhance the reliability and extend the working life of machines and devices while reducing their operating energy requirements.