高速列车受电弓纯炭滑板材料的结构-功能一体化调控及抗磨机理研究

Pantograph contact strip is the core component of electric locomotive and nearly all of the existing contact strip materials of high-speed trains are made from carbon materials. The relationship between "graphene functional modification-mechanical property, electrical property coordination-microstructure characterization-organizational structure optimization" is taken as the research idea of this project, which is aimed at the defects of the existing pantograph pure carbon strip materials that difficult to both acquired wear resistance, inhibition arc erosion and high conductivity of the overall performance. Intend to use amphoteric sulfonated graphene to improve the comprehensive performance of pure carbon strip materials, the structure of "skeleton-branched chain" is designed, that is, sulfonated graphene as the carbon phase of the "skeleton", with its own hydrophilic and modified imported lipophilic group as a "branch chain" anchored on different carbon phases, a new type of pure carbon strip material was prepared by dispersion and kneading, rolling and grinding, extrusion and calcination. The effects of sulfonated graphene on the homogeneity of paste and the interfacial properties of carbon strip were systematically investigated. Under high-current conditions, we will study the effects of sulfonated graphene on the wear resistance performance of pure carbon strip, and expound in depth the mechanism of sulfonated graphene with the pull effect among different charcoal phase and in inhibiting the form and spread of the microcracks, and then construct a new ways in regulating the structure-functional integration of carbon strip. The research results will provide the guidance and theoretical basis for the research and design of high performance carbon graphite materials, which will be helpful to improve the comprehensive performance of carbon strip materials.

受电弓滑板是电力机车的核心部件，现有高速列车受电弓滑板的选材均来源于炭质材料。本项目针对现有受电弓纯炭滑板材料难以兼具抗折抗磨、抑弧高导综合性能的缺陷，提出以“石墨烯官能团改性-力、电学性能协调-微结构表征-组织结构优化”之间的关联为研究思路，拟采用双亲型磺化石墨烯改善纯炭滑板材料的综合性能，通过设计“骨架-支链”结构，即以磺化石墨烯作为炭相间的“骨架”，以其自带的亲水和改性导入的亲油基团作为锚定在不同炭相上的“支链”，经分散混捏、轧片磨粉、挤压焙烧制得新型纯炭滑板材料。考察磺化石墨烯对糊料均质性及炭滑板材料界面性能的影响；研究在高载流条件下，磺化石墨烯对纯炭滑板材料抗磨性能的影响；阐明磺化石墨烯在不同炭相间的拉拽效应和抑制微裂纹萌生、扩展的机制，进而构建炭滑板材料结构-功能一体化的调控新方法。研究成果将为高性能炭石墨材料的研究和设计提供理论基础，对改善炭滑板材料的综合性能具有指导意义。

本项目针对现有受电弓纯炭滑板材料难以兼具抗折抗磨、抑弧高导性能的缺陷，采用双亲型磺化石墨烯改善纯炭滑板材料的综合性能，通过设计“骨架-支链”结构，即以磺化石墨烯作为炭相间的“骨架”，以其亲油基团作为锚定在不同炭相上的“支链”，按典型炭素材料制备工艺制得新型炭质复合材料。项目借助微结构表征及分析方法，以“石墨烯官能团改性-力、电学性能协调-微结构表征-组织结构优化”为研究思路，阐明磺化石墨烯在不同炭相间的拉拽效应和抑制微裂纹萌生、扩展机制，探究磺化石墨烯对炭质复合材料力学及抗磨性能的影响机制。研究发现：(1)磺化石墨烯的均匀引入有效抑制炭石墨材料在制备及服役过程中的微裂纹产生与扩展，采用热模压掺入1wt%磺化石墨烯增强复合材料的力学性能明显提高，抗折强度和抗压强度达到57.5± 3.8MPa和121.0± 2.3MPa，分别是未添加磺化石墨烯炭石墨材料的2.6倍和2.4倍；(2)采用模压预成型、热挤压定型和一次焙烧制得含1wt.%磺化石墨烯的炭滑板较未添加磺化石墨烯的炭滑板的载流抗磨性能有显著改善。在220V、转速12000r/min下，与未添加样相比，用1wt.%磺化石墨烯增强的炭滑板材料的磨损率在正常条件下降低了50.0%，在潮湿条件下降低了51.0%。(3)采用真空热压烧结在钴合金化的铜基电接触材料中引入均匀分散的石墨烯，充分发挥石墨烯固体润滑剂的作用，改善复合材料的耐磨性。Cu-0.2GNPs-0.25Co的磨损率8.3×10-5 mm3/(N·m)，仅为纯铜磨损率41.6×10-5 mm3/(N·m)的20%。含石墨烯的电接触复合材料耐磨性能的提高归因于钴合金化诱导形成界面无定形层，增强了Cu/GNPs界面结合力；(4)在糊料中均匀分散的低维材料在碳石墨材料中的导入可实现不同碳相同步热缩的调控。引入磺化石墨烯构筑的骨架结构可有效改善不同碳相之间的相互作用形式，提高了焙烧过程中的结焦值，从而提高了炭质复合材料的结构完整性、力学及抗磨性能。该研究成果为纯炭滑板材料及炭质复合材料结构-功能一体化的调控提供了新方法，为高性能炭石墨材料的研究和设计提供理论基础。