Strain engineering induces the achievement of superlubricity in a double-walled carbon nanotube due to the formation of a mismatched lattice constant between the two carbon nanotubes.

Graphene is a promising nano-additive in polymer-based coatings to improve their tribology performance under current-carrying conditions due to its unique electrical, thermal and mechanical properties. Here, the current-carrying friction behavior of polyamide-imide (PAI) matrix composite coating incorporated with graphene prepared by high-temperature solicitation is studied using a homemade ball-on-disc tribometer. It is revealed that both coefficient of friction and wear rate of graphene/PAI composite coating are lower than those of pure PAI coating. The reduction in wear rate of PAI coating by the addition of graphene is increased by >7 times when the current intensity rises from 0 to 4.5 A, indicating better tribology enhancement of graphene under current-carrying conditions than under dry conditions. Post-test surface analyses demonstrate that the tribology enhancement mechanism mainly arises from the quick in-situ formation of graphene-rich transfer film promoted by current heat and the highly suppressed arc erosion on worn surface. This work provides a novel method to broaden wear resistant polymer-based coatings in the field of current-carrying lubrication application.