真空电场下碳膜-离子液体的界面行为特征与摩擦学性能研究

Carbon-based film-ionic liquids synergetic lubricating materials have broad application prospects in the field of space mechanism. With the rapid development of the sapce technology in China, many urgent scientific problems need to be solved for the lubrication materials. The relationship between the wetting behaviours and lubricating properties of lubricating materials under an external electric field in a vacuum environment are one of the most important basic scientific problems. But the research about it is rarely investigated. The ionic liquids with the differen surface tension and the carbon-based coatings with the different microstructures and composition will be prepared to realize the solid-liquid synergetic lubircating materials. The wetting, adhesion and tribological behavior of synergetic lubricating materials under an external electric field in a vacuum environment will be investigated, finding the relationship of wetting and lubricating. The effect of the microstructure and composition of the carbon films, the cation-anion and functional group of the ionic liquids on the wetting, adhesion, slip behavior and tribolgical properties will be investigated. The relationship between the surface and interfacial behavior and tribological characteristic and impact mechanism under a vacuum condition will be discussed. The electrowetting model and voltage-controlled friction mechanism will be revealed. This proposal will promote a new understanding of the wetting behavior and the voltage-controlled friction performance for the synergetic lubricating materials, and have the important theoretical significance and applicable value for improving the lubrication properties and technologies of the space charged-moving components.

碳基薄膜-离子液体复合润滑材料在空间机械领域具有广阔应用前景。随着我国空间机械领域的飞速发展，润滑材料面临许多亟需解决的科学问题，其中真空带电运行部件的表面润湿行为与润滑性能关系规律是重要的基础科学问题之一，而有关真空电场对离子液体在碳膜表面润湿行为、摩擦学性能及其关系规律的研究鲜见报道。本项目拟以选择不同表面张力的离子液体与不同表面形貌、组分碳基薄膜组成的复合润滑体系为研究对象，考察碳膜微观结构、组分、离子液体的阴阳离子、官能团等对真空电场条件下离子液体在碳膜表面的润湿、粘附、滑移等行为和摩擦学性能的影响，探讨该复合润滑材料的润湿、粘附、滑移等行为与润滑性能间的关系规律及机理，揭示真空环境中离子液体的电润湿模型和复合材料的电控摩擦机理。该项目的实施将对真空电场环境下碳膜-离子液体的润湿等界面行为特征和电控润滑性能有新的认识，对提高空间带电运行部件的润滑性能和润滑技术具有重要的意义。

随着我国航空航天等空间领域的快速发展，运动部件的摩擦与润滑关系到其长效稳定地运行，而真空带电运行部件表面固-液间的润湿与润滑关系规律也是急需解决的科学问题之一。碳基薄膜-离子液体复合润滑材料在空间机械领域具有广阔的应用前景。本项目设计合成了多种无腐蚀、热稳定性能良好和润滑性能优异的离子液体。利用物理气相沉积技术制备了具有致密结构和良好机械性能的掺杂元素的碳基薄膜。较低的碳膜表面粗糙度、离子液体表面张力和离子液体与基底间较高的粘附力均有利于离子液体在碳膜表面的铺展和润湿。真空摩擦条件下碳基薄膜提供了良好的承载性能，离子液体不但起到阻止了碳膜与金属对偶间的直接接触，有效避免了薄膜和钢球间的粘着和冷焊现象，还起到了液体润滑剂的良好润滑作用，因此碳基薄膜-离子液体复合润滑材料在真空条件下具有良好的摩擦学性能。离子液体在碳基薄膜表面的润湿现象用Wenzel方程来表达，电润湿符合Young-Lippmann方程。离子液体在碳基薄膜表面的接触角随着外加电压的增大而减小，这是由于外加电场降低了离子液体的表面张力所致。真空环境中碳膜-离子液体复合润滑材料的电控摩擦机理为外加电场降低了离子液体的表面张力，增加了碳基薄膜-离子液体界面间对阴阳离子的吸附力，改变了摩擦对偶间边界润滑膜的组分和厚度，从而提高了其润滑性能。这些研究结果不但拓宽了离子液体和碳基薄膜的应用范围，而且对丰富和发展润湿与润滑关系规律、电控摩擦机理等摩擦学理论具有重要的学术价值，为空间带电运行部件的润滑防护提供一定的技术和理论支持。