爆炸喷涂石墨烯改性涂层的工艺及自润滑耐磨机制研究

Study on Prepare ProcessTechnology and Self-lubrication and Wear Resistance Mechanism of Graphene Modified Coating by Detonation Spraying

摘要:

为了降低WC-12Co耐磨涂层的摩擦系数，采用四种制粉工艺（湿法球磨、湿法搅拌、烧结破碎、喷雾造粒）将石墨烯复合于WC-12Co粉末中，基于爆炸喷涂技术制备了石墨烯自润滑耐磨涂层。借助SEM、EDS、Raman等手段分析了不同制粉工艺对获得粉末及涂层中石墨烯的组织形貌、物相组成。采用显微硬度计、万能拉伸机研究了涂层的力学性能。采用UMT-2摩擦磨损试验机研究了涂层的摩擦磨损性能。结果表明，喷雾造粒工艺可实现更多的石墨烯在WC-12Co颗粒表面的均匀、紧密粘附，涂层内部石墨烯含量较高，且仍以透明状、薄层状态嵌合在组织内部，结合强度约68MPa，硬度约940HV0.3，石墨烯涂层摩擦系数降低约25%，石墨烯在摩擦过程中不断裸露于磨痕表面，在微区内形成润滑膜，起到较好的自润滑、减磨效果。

Abstract:

Aiming to reduce the friction coefficient of WC-12Co wear-resistant coating, the self-lubricating coating was developed by adding graphene to WC–Co coating deposited via detonation gun spraying. In this study, four powder processes, including wet ball milling, wet mixing, spray granulation, and sintering and crushing, were used to obtaingraphene/WC–Co composite powders. The presence, microstructure and phase composition of graphene in powder and coating were analyzed by means of SEM, EDS and Raman. The mechanical properties of the coating were studied by the microhardness tester and the universal tensile machine. When the spray granulation process is used to prepare the composite powder, a greater amount of graphene covers the surface of the WC–Copowder, and the transparent thin-layered structure of the graphene remains unchanged. The bonding strength and hardness of the resultant coating are approximately 68 MPa and 940 HV0.3, respectively. Graphene modification causes a 25% reduction in the friction coefficient. During the friction process, the graphene constantly forms a lubricating film that serves as an excellent self-lubricating layer.