▎ 摘　　要

Ceramic coatings were formed on the surface of Ti6Al4V alloy drill pipe by plasma electrolytic oxidation (PEO) technology in the silicate electrolyte with and without graphene nanosheets. Voltage-time responses were recorded. The microstructure, elements distribution and phase composition were investigated by SEM, TEM, EDS and XRD. The basic physical properties and wear resistance were studied. The morphology of wear tracks was observed by SEM and three-dimensional microscope. Results indicated graphene nanosheets successfully incorporated in the ceramic coating. The main elemental components were Ti, Si and O. They were crystallized and composed of anatase and rutile. The coating with graphene nanosheets showing the morphology and structure of flatter and less pores was superior to the coating without graphene nanosheets exhibiting rugged and more pores, and the microhardness of the coating with graphene nanosheets was 1250 HV which was noteworthy improved in contrast with the coating without graphene nanosheets of 870 HV. Wear test results showed the coating with graphene nanosheets displayed extremely significant wear resistance due to the physical barrier of graphene nanosheets. In summary, the application of graphene nanosheets to improve the wear resistance of titanium alloy drill pipe is a promising and promotional research. (C) 2019 Elsevier B.V. All rights reserved.