Effect of interlayer bonding and stacking structure on the tribological properties of graphene oxide coatings

Abstract

Graphene oxide (GO) coating is widely used while its lubricating performance depends on the stacking structure and operational environment. Here, GO coatings were fabricated by spraying, spinning, and electrostatic self-assembly using Cu²⁺ ion as the coordination. The influence of stacking structure on the tribological properties in humid air, dry nitrogen, and vacuum were evaluated. The results show that Cu²⁺-coordinated self-assembled coatings with strong interlaminar bonding and ordered stacking structure exhibit lower wear under test conditions, especially in a vacuum with a stable friction coefficient of ∼0.03, benefit from the increased contact area between GO sheets, reduced stress concentration, inhibited hydrogen bonding between GO and environmental water, and passivates the surface defects of the coating when subjected to shear stress.