▎ 摘　　要

Graphene oxide (GO) nanosheet coatings are considered as promising solid lubricants. They, however, still suffer short lifetime and low load capability, limiting their further mechanical engineering industrial application. In this work, copper ions are in-situ incorporated into GO nanosheet coatings by applying a low potential towards a copper substrate in a GO suspension. The generated copper ions not only induce chemical cross-linking of neighboring GO nanosheets via bounding to carboxylic acid groups at the edges of individual GO nanosheets but also reduces the C-O functional groups on their basal planes. These factors facilitate retaining GO nanosheets with few structural deteriorations in the contact interface when copper covered with these coatings slides against steel ball. Consequently, the COF is as low as 0.17 even under a maximum Hertz contact pressure of 1.1 GPa, the durability is 10 times higher than the air-sprayed GO coating and the wear rate of the copper substrate is reduced more than 20 times compared with the bare copper substrate.