Simple preparation of ultra‐thin white g‐<scp>C₃N₄</scp> nano‐sheets and their use as nanofillers to enhance the tribological properties of epoxy composite coating

Abstract Graphite phase carbon nitride (g‐C 3 N 4 ) has shown great promise as a functional filler in the field of friction. But at present, research in the field of friction mainly focuses on bulk g‐C 3 N 4 or obtaining g‐C 3 N 4 nano‐sheets through inefficient exfoliation strategies, which greatly limits its industrial applications. In the study, a simple and effective secondary calcination method has been developed to successfully fabricate ultrathin white g‐C 3 N 4 nano‐sheets. The mass ratio of the same volume of bulk g‐C 3 N 4 and white g‐C 3 N 4 nano‐sheets was as high as 50:1. Subsequently, the tribological performance of epoxy (EP) composite coatings containing different contents of bulk g‐C 3 N 4 and g‐C 3 N 4 nano‐sheets were researched. The EP composite coatings containing 1 wt.% g‐C 3 N 4 nano‐sheets possess the lowest wear rate and friction coefficient in all samples, which is attributed to the two‐dimensional planar structure and high specific surface area of g‐C 3 N 4 nano‐sheets make it easier to transfer to the dual surface to form the excellent transfer film under the action of friction force, so that the friction mainly occurs between a dual surface and a transfer film, which effectively improves the tribological performance of the coatings. Highlights Ultrathin white g‐C 3 N 4 nano‐sheets were prepared by secondary calcination. EP‐1 wt.% g‐C 3 N 4 nanosheets show the best tribological properties. g‐C 3 N 4 nanosheet is easy to transfer to dual surfaces to form transfer films. This work provides guidance for the application of nanofillers in tribology.