碳纳米管束/石墨超润滑电刷摩擦磨损研究

Electric brushes are common devices in the electric drive machines. Due to friction and wear, the life of brushes is extremely short. However, in some harsh conditions, electric brushes still exhibit excellent performances and remain irreplaceable. In recent years, we have witnessed the rapid development of the high-speed railway in China. It turns out that the traditional pantograph slider material can be easily worn and destroyed. This poses a number of problems and, in particular, limits the further speed increase. New pantograph slider materials are urgently and intensely needed. Opportunity is now presented to develop a whole new class of high-performance superlubricity brushes using aligned films of carbon nanotubes and graphite, possessing super-compressibility, high electrical and thermal conductivity, excellent mechanical strength, tunable friction behavior and environmental insensitivity. However there are barely thorough works on the mechanisms of carbon nanotube/graphite brushes. The present project aims to systematically study the effects of environment, normal pressure and current density on carbon nanotube/graphite brushes through experimental and theoretical investigations. The objectives are to reveal the governing mechanisms and develop specific experimental techniques which serve as bases for designing and fabricating efficient carbon nanotube/graphite brushes for the railway industry.

电刷在接触电动机构中无处不在，有刷电机摩擦磨损严重，寿命短，但有刷电机在重载、高电流密度、腐蚀环境、高温等特殊环境下依然有着不可替代的优势。另一方面，随着中国高速铁路的快速发展，速度的提高对高铁受电弓滑块材料的性能要求越来越高，传统的滑板材料容易因摩擦磨损而损坏，远不能满足需求。在接触的电极上分别生长或转移石墨和碳纳米管束，利用碳纳米管束与石墨的超润滑性质可制成一种全新的、性能优越的超润滑电刷。目前还未见碳纳米管束/石墨超润滑电刷的相关研究，摩擦力与滑移速度的依赖关系不清楚，超润滑电刷界面的导电性与滑移速度和正压力的关系，环境对碳纳米管电刷的影响，至今只有极少的报道。本项目拟开展对这个方面系统、深入的实验和理论研究，目标是发现碳纳米管束/石墨电刷的独特新现象、揭示有关机理、初步建立起一套碳纳米管束/石墨电刷的理论体系，为碳纳米管电刷的实际应用提供指导作用。

有刷电机在重载、高电流密度、腐蚀环境、高温等特殊条件下有着不可替代的优势，但是有机摩擦磨损严重，寿命短。另一方面，随着中国高速铁路的快速发展，速度的提高对高铁受电弓滑块材料的性能要求越来越高，传统的滑板材料容易因摩擦磨损而损坏，远不能满足需求。在接触的电极上生长或转移碳纳米管束/石墨，利用碳纳米管束/石墨的超润滑性质可制成一种全新的、性能优越的超润滑电刷。为此，本项目系统地开展了碳纳米管束/石墨超润滑电刷的摩擦磨损性能研究。首先，从微纳米尺度出发研究了摩擦磨损的机理，主要开展了电子摩擦的作用机理、纳米尺度磨损和非公度角对超润滑的影响机理研究，建立了摩擦磨损的理论模型，这为后续的宏观尺度超润滑的应用研究奠定了理论基础；其次，为了满足超润滑电刷的研究需求，搭建了超润滑电刷摩擦磨损测量平台，这为宏观尺度机理研究提供了工具；然后，在宏观尺度开展了电刷机理研究，揭示了环境、温度和速度等主要因素对电刷性能影响的机理；最后，利用分子结构力学方法分析了三维碳纳米管电刷的破坏和屈曲。本项目不仅可以丰富摩擦学和超润滑的基础理论，而且也有助于制造接触式电刷和高铁受电弓滑板系统。