石墨烯/碳纤维多尺度混杂铜基自润滑材料构建及减摩耐磨机制研究

For high-performance copper matrix self-lubrication composites, the novel spatial configuration and its controllable preparation of solid lubricants are the important researching contents. In the current composites, the antiwear and friction-reducing properties can not be reasonably concerned simultaneously. Moreover, the solid lubricants are hard to be uniformly dispersed. Aiming at these problems, we propose to introduce a two-dimensional layered graphene and short carbon fiber multi-scale hybrid lubricants to collaboratively modified the copper matrix. By the combination of graphene oxide aqueous solution as a dispersion medium, freeze-drying and reduction methods, the uniformly mixed powders containing graphene, carbon fiber and copper particles will be fabricated, and then which are rapidly sintered to the high-dense bulk composite using the spark plasma sintering. Based on our preliminary research, such bulk composite exhibited the remarkable antiwear and friction-reducing effect. The structure and interface of the composites will be systematically investigated, and whose evolution law and formation mechanism will be clarified. The effect of microstructure and preparation parameter on friction and wear properties will also be studied. The research work will establish the relationship between microstructure and macroscopic properties of composites, and then reveal the role and corresponding mechanism of graphene and carbon fiber multi-scale architecture on improving friction and wear properties of copper matrix, which will provide the necessary theoretical and experimental basis for the application and exploration of the high-performance composites.

润滑组元空间配置新模式及其可控制备新策略是高性能铜基自润滑材料研究领域的重要内容。针对目前铜基自润滑材料减摩性能和耐磨性能不能合理兼顾、固体润滑剂难以分散的难题，本项目提出二维层状石墨烯和碳纤维多尺度混杂协同改性新技术，探索利用氧化石墨烯水溶液作为分散介质辅以冷冻干燥还原方式获得分散性良好的石墨烯/碳纤维/铜复合粉体，结合放电等离子快速烧结技术最终实现高致密多尺度新型铜基自润滑材料的构建，初步研究结果显示材料减摩耐磨效果显著。与此同时，系统研究材料的界面特性和显微组织结构特征，阐述材料微结构的影响演化规律及其组装形成机制；探究材料组分结构和制备工艺参数对该多尺度自润滑材料摩擦磨损性能的影响，深入挖掘材料的减摩耐磨潜力，建立材料微结构减摩耐磨关系模型，揭示石墨烯/碳纤维多尺度复合构型优化铜基体摩擦磨损性能的作用，并阐明相关作用机制，为高性能铜基自润滑材料的应用开发提供必要的理论和实验依据。

固体自润滑材料在无油或少油润滑状态下具有独特的优越性。铜基自润滑材料具有优异摩擦学特性和良好的导电导热性能等，其在机械电气工程中有着广泛的应用，而润滑组元空间配置新模式及其可控制备新策略是高性能铜基自润滑材料研究领域的重要内容。本研究针对目前铜基自润滑材料减摩性能和耐磨性能不能合理兼顾、固体润滑剂难以分散的难题，利用二维层状石墨烯和碳纤维多尺度混杂协同改性新技术，将氧化石墨烯水溶液作为分散介质并辅以冷冻干燥还原方式获得了石墨烯/碳纤维/铜复合粉体，石墨烯/碳纤维固体混合润滑剂和电解铜粉颗粒呈现良好的分散性状态，部分表面褶皱片层状石墨烯贴覆在铜粉和碳纤维表面。本研究借助粉末固态烧结法实现了石墨烯/碳纤维多尺度混杂铜基自润滑材料的构建，系统研究了材料的界面特性和显微组织结构特征，阐述材料微结构的影响演化规律及其组装形成机制，石墨烯/碳纤维均匀分布在铜基体中，碳纤维呈现不同的空间取向分布，石墨烯呈现三维非连续网状分布特点。本研究深入研究了材料组分结构对石墨烯/碳纤维多尺度自润滑材料力学和摩擦磨损性能的影响，石墨烯/碳纤维多尺度混杂增强体相比石墨烯或碳纤维单一增强介质对铜基体的硬度和室温杨氏强度具有更好的增强效果，且铜基复合材料的硬度和室温拉伸杨氏强度随着石墨烯添加量的增加而增加；对比纯铜和单一石墨烯增强铜基复合材料，石墨烯/碳纤维多尺度混杂铜基自润滑材料减摩耐磨效果显著，具有更低的摩擦系数和磨损率；揭示并阐明了石墨烯/碳纤维多尺度复合构型优化铜基体摩擦磨损性能的作用和相关作用机制，为高性能铜基自润滑材料的应用开发提供必要的理论和实验依据。