Lubrication properties of graphene under harsh working conditions

Graphene materials considered to be promising candidates for next-generation lubricants has been explored and summarized extensively, owing to their atomic-level lamellar structure and extremely low interlayer shear van der Waals barrier. However, the lubrication properties of graphene under harsh working conditions, including elevated temperature, heavy load, high vacuum, special atmosphere environment and electric or magnetic field environment, have not been systematically summarized and thoroughly analyzed. Meanwhile, the effect of graphene on the behavior of boundary tribofilm have not been systematically reviewed. This review focuses on the application of graphene family materials in harsh working conditions. Firstly, an overview of the graphene categories is presented, and then the application of graphene in harsh working conditions is summarized. Besides, the effect of graphene family materials on the behavior of boundary tribofilm is examined. Accordingly, the lubrication mechanisms of graphene are summarized, which mainly include adsorption protection of boundary tribofilm, graphene microstructural transformation, graphene internal slippage, and micro bearing rolling-sliding effect. Finally, the critical challenges and future prospects for the application of graphene as next generation lubrication materials are discussed. This article aims to boost further development of graphene as a candidate to solve the lubrication bottleneck of equipment in harsh working conditions such as space, deep sea, deep earth, nuclear energy and MEMS. (c) 2023 The Authors. Published by Elsevier Ltd.