不锈钢滚动摩擦/载流行为的耦合关系及机制研究

Rolling tribology with current was a fundamental issue in the traction power return system, high-voltage motor, etc, which was a key safety factor in such engineerings. Unlike the close sliding contact, the rapid touching and separating of materials in contact area resulted in the variational statuses of loading and current-carrying on the surfaces during rolling. However, the related researches have not been carried out up to now. Due to the coupling effects of tribology and current, the present issue was not a simple extension or superimposition of pure mechanical rolling and electric sliding. The proposed project is hereby focused on investigating the triboelectric coupling behaviors and the related mechanism of steel self-matched rolling pairs. Firstly, the effects of various experimental conditions on the triboelectric properties and their coupling relationships will be investigated. Based on the analysis of the microstructures and components on the worn surfaces and wear debris, the micro mechanisms of mechanical and electrical damages can be revealed and their correlation will be clarified. Finally, the coupling framework of tribology/current during the rolling contact will be set up, and the specials of rolling triboelectric behaviors will also be discussed. The proposed project research is expected to enrich the art of the current state of triboelectric theory, and also to supply constructive suggestions for the design and safe operation of the engineerings in traffic, energy, etc.

滚动载流摩擦广泛存在于轨道交通回流系统、高压机电等工程领域，已经成为影响设备安全运行的关键因素。与滑动载流摩擦不同，滚动摩擦副接触区材料快速的接触和分离导致其承载和受流始终处于动态变化，但相关研究相对滞后。由于摩擦因素与载流因素之间的耦合作用，现有纯机械滚动与滑动载流研究的简单延伸或叠加并不适用于滚动载流摩擦。为此，本项目拟以不锈钢自配副为例，系统开展滚动摩擦/载流行为的变化规律、耦合关系及机制研究。在阐明不同载流摩擦条件下材料滚动摩擦学性能、载流性能变化规律和耦合关系的基础上，结合结构分析和成分分析等手段，揭示摩擦过程中材料机械损伤和载流损伤的微观机理及耦合关系，进而建立滚动摩擦/载流耦合机制并探讨滚动载流摩擦的行为特性。该研究不仅有助于丰富载流摩擦学理论，而且有望为交通、能源等领域的滚动载流摩擦学问题提供有益借鉴。

利用载流摩擦副传导电流是运动部件之间输送电功率和电信号的主要方式之一。基于滚动摩擦低摩擦系数、低磨损率的先天优势，滚动汇流环应运而生，已应用于航母预警雷达、导弹信号传输系统、国际空间站太阳能电池板。滚动载流摩擦副性能特性和失效机制的基础研究，是实现其高可靠性运行和合理设计的理论前提。.为此，本项目首先完成了滚动载流摩擦试验机试制，然后研究了载荷、电流、湿度等工况对摩擦/载流性能的影响规律，不同工况下滚动载流摩擦失效规律和失效机制。比较重要的结果有：.1、对滚动载流摩擦副平稳运行状态下摩擦/导电行为开展研究，试验结果表明其性能受到载荷和电压的耦合影响：随着载荷的增加，纯机械摩擦系数和载流摩擦系数下降并趋于稳定；较高载荷有利于接触表面微凸峰形变因而真实接触面积增加，进而降低接触电阻。相同载荷下载流摩擦面粗糙度更低，但可能由于电阻热引起的材料黏着，使得载流摩擦系数高于同等载荷下的单纯机械摩擦系数，并随着电压的增加而增加。 .2、滚动载流摩擦副失效受载荷、电流影响：滚动载流摩擦副寿命随载荷的增加而降低、随电流的增加而降低，失效时主要体现为摩擦系数的持续上升。.3、湿度是影响滚动载流摩擦性能和失效的显著因素。相对湿度的增加和电流的介入均增加表面氧化，载流磨损表面氧化机制包括机械作用引发的摩擦化学氧化和电流引发的电化学氧化。相对湿度的增加能够显著降低滚动载流摩擦副寿命。.本项目揭示了滚动载流摩擦副性能基本规律和失效机制，有望为未来航天器、雷达等高端装备中滚动汇流装置的长寿命设计和安全服役提供基础理论支撑。