航天器钛合金表面强韧-润滑梯度涂层构筑及其表界面行为研究

单一强韧、或润滑防护难以满足航天器轻量化钛合金运动部件表面对高承载、耐磨、减摩的综合性能需求。本项目拟借助等离子渗氮/渗碳结合气相沉积技术在涂层结构及其表界面特性方面高度可调的突出性优势，设计发展钛合金表面强韧-润滑梯度涂层；探讨模拟空间环境条件交变耦合摩擦过程诱导的润滑表层重构行为规律及其对低摩擦、高耐磨、低（摩擦）噪声性能的影响机理；研究强韧-润滑子层界面、强韧子层-钛合金基体界面间的结构与力学适配行为，揭示其对摩擦学性能的影响规律；基于涂层生长热力学与动力学理论、涂层接触力学、以及涂层拟服役空间环境下的性能需求，优化梯度涂层组分与结构，实现对梯度涂层结构、界面结构与力学适配以及跨环境适应性能的精确调控，赋予钛合金表面强韧、耐磨、低摩擦、低噪声、跨环境适应性能的有效统一。研究工作将为我国未来航天工程轻合金运动部件的表面润滑防护提供理论依据和技术支撑。

The high strength-to-weight ratio titanium alloy moving components in the coming spacecraft asks for a package of high bearing performance, high wear resistance and low friction behaviors, the need of which can’t be met by the simplex coating only with high strength-toughness, or lubrication performance. To sort out this fundamental scientific problem, we are planning to design and construct the gradient coating consisting of the underlying strength-toughness sub-layer and top lubrication sub-layer, via a duplex technology of plasma nitriding/carburizing and vapor deposition, which possesses the highly adjustable advantage for the coating structure and surface/interface behaviors. The restructure behaviors of the lubricant layer surface caused by rubbing under the simulated variable space environments will be systemically studied to reveal the mechanism of the effect of restructure behaviors on the friction, wear and rubbing noise of coating. Furthermore, the coating adaptive behaviors of structure and mechanical properties of the interfaces between strength-toughness sub-layer and lubrication sub-layer, and the one between strength-toughness sub-layer and titanium alloy substrate will be studied to clarify the effect of the adaptive behavior on the tribological performances under the simulated variable space environments. On basis of the thermodynamic and kinetic theories of film growth in plasma, contact mechanics of coating and the integrate requires of excellent performances of lubricant spacecraft coating under the service environment, the composition and structure of coating will be further tailored to optimize the structure, the interface behaviors (between strength-toughness sub-layer and lubrication sub-layer, and the one between strength-toughness sub-layer and titanium alloy substrate) and the excellent environmental adaptability to finally endow the high strength/toughness, high wear resistance, low friction, low rubbing noise, good environmental adaptability of coating. Our aim is to develop high performance gradient coating to provide the theory basis for the advanced material and technology for some light alloy moving components in the coming spacecraft in China.