真空环境下滑动电接触部件损伤机理及长寿命摩擦副体系设计

Friction and wear behaviors of electrical contacting friction counterpart materials have been found to play a significant role on the reliability and stability of aerospace system during signal switch and transmission process. However, it also suffers many influences of complicated factors such as material structure, environment, operating condition etc. This project aims to satisfy the urgent necessary for electrical contacting friction counterpart materials in space field with long life-time, low friction, high wear resistance and cruel environment resistance. Systemic studies are carried out on the friction and wear properties in coupling of material composition and structure, multiple environments (atmosphere, vacuum, atomic oxygen and irradiation), multiple factors (current carrying, temperature/pressure, microelectric arc) etc., and then the interaction mechanism of micro-discharge, the scientific essence of wear dynamics, and the design principle for electrical contact friction counterpart materials are established on the basis of calculation simulation and experimental results. Bearing these aspects in mind, we propose to utilize the epitaxial growth, low-temperature vapor deposition, catalytic induction etc. technologies, and develop new types of long life-time, low friction, high wear resistance and high conductivity electrical contact friction counterpart materials through the component design and structure controlling. The acquisition of those technologies and life extension methods of high-performance electrical contacting materials is of great theoretical and practical values for improving the service performance of electric contact parts, solving the bottleneck problem of the spacecraft reliability and development of long life-time orbiting spacecrafts.

航天工程电接触摩擦副材料的摩擦磨损行为是决定系统信号转换和传输的可靠性、稳定性、精确性和使用寿命的关键，但其受到材料结构、环境、工况等诸多复杂因素的综合影响。本项目针对航天器对长寿命、低摩擦、高耐磨、耐苛刻环境电接触摩擦副材料的需求，系统研究材料组成和结构、多环境（大气，空间真空、原子氧、辐照环境）、多因素（载流、温度/压力、微电弧）等耦合作用下的摩擦磨损性能，通过计算模拟和实验相结合，明确微放电交互作用机制及磨损动力学的科学本质，建立多因素耦合作用下电接触摩擦设计和磨损寿命预测的理论模型；在此基础上，利用外延生长、低温气相沉积、催化诱导等技术，通过组分设计和结构控制，研制出新型长寿命、低摩擦、高耐磨、高电导的电接触摩擦副材料，掌握高性能摩擦副材料的制备技术和延寿方法，这对改善电接触部件的摩擦状态、解决制约航天器可靠性和寿命的瓶颈问题、发展长寿命在轨航天器具有重要的理论意义和重大应用价值。

针对空间滑环电传输滑动服役特殊工况，建立了真空载流模拟评价条件，可在线监测摩擦系数、电噪音以及接触电压的变化，进一步结合电接触理论仿真模拟，揭示了金基（高导电、高摩擦）和二硫化物基（低导电、低摩擦）两类主要空间润滑材料在真空载流-温度/压力耦合环境的微放电交互作用机制，提出了电接触摩擦副优化接触模型以及硬承载+软润滑功能层材料设计原则。基于上述机理认识指导，在现役电镀金材料体系方面，突破低应力叠层择优取向和晶粒尺寸调控设计以及电接触条件优化等关键技术，实现了寿命的大幅提高，完成等效8年的台架跑合试验验证，通过了航天系统组织的工艺鉴定，满足了现有型号可靠服役要求；在新型导电润滑材料体系探索方面，突破了低温沉积关键技术，利用真空气相沉积方法发展出金薄膜材料，较传统电镀金膜层，展现出光滑致密、高硬度等优势，大幅抑制了载流电弧的产生，真空载流耐磨与接触电噪音性能进一步显著提高；突破外场催化诱导石墨烯结构碳膜制备、宏观超滑摩擦表界面设计、多层精细结构设计等关键技术，发展出Au/石墨烯以及Au/二硒化铌多层复合薄膜，实现了在保持接触高电导性的基础上，摩擦系数、寿命等关键性能指标较现役金电镀膜层改善1个数量级以上。目前已完成实际滑环零件（信号盘和功率盘）的镀制，择机应用考评。本项目在真空载流润滑机理、宏观超滑表界面设计原理以及在材料关键技术方面的突破，为解决制约我国现役航天器可靠性和寿命的瓶颈问题以及未来发展超长寿命在轨航天器都提供了有利的理论和技术支持。