▎ 摘　　要

Frictional behaviors of graphene, which have been generally investigated on elastic or rigid substrates, are carefully discussed here in metal-graphene systems through molecular dynamics simulations. The nanoscratched process and topography analysis are conducted to study the friction on a composite surface, where the layer number, embedding depth, and interval of graphene are considered as major factors. The friction coefficient of monolayer graphene on an Al surface is obviously higher than the reported results on an elastic or rigid substrate, while the variety of substrates seems to make no much difference to frictional results on multilayer graphene. Graphene is actually helpful for reducing friction on composite surfaces, but the friction coefficient on composite surfaces will rocket from 0.045 to 0.835 with the rise in the embedding depth of graphene, and this range of data is consistent with experimental values measured on Al-graphene composite coatings. Moreover, a larger distance between graphene may lead to an increase in the overall friction coefficient, which can also be proved by electroplating experiments under a low concentration of graphene. (c) 2021 Author(s).