高真空环境下a-C:H复合薄膜的结构演变、超润滑失效机制与延寿

In recent years, the development of national aerospace technology urgently needs to use the super-lubricating films with ultralow friction, long wear-life and high reliability in high vacuum. Amorphous hygdrogenated carbon (a-C:H) film presents ultralow friction coefficient (as low as 0.004), while its wear-life is very short, which inhibit the use in space. In this project, the friction and wear behaviors of the a-C:H film will be investigated systematically in different vacuum environments (as different vacuum degree, partial pressure of N2, O2 and H2 and different temperature) to reveal the effect of gas adsorption, frictional temperature-rise and contact stress on the vacuum tribological properties. Emphasis will be on the evolution rules of film microstructure as surface morphology, composition and chemical-state, and on the chemical/physical essence on the worn surface during the vacuum friction. The theoretic mechanisms of super-lubricating failure of a-C:H film in high vacuum will be established from the intrinsic factors (as film microstructure) and external factors (as environment and friction conditions). Based on the above researching results, novel super-lubricating a-C:H films with ultralow friction (<0.005), long wear-life and high reliability in high vacuum environment will be developed via unbalanced magnetron sputtering combined with plasma enhanced chemical vapor deposition. The multiplex-composited microstructure of the films are designed and dominated by choosing traditional vacuum lubricants as MoS2 and/or WS2 embedded in the film matrix. The major research achienements of the project have great theoretical significances and application values to resolve the space lubricating problems.

我国空间技术的发展，对真空中具有极低摩擦系数和长寿命的超润滑薄膜提出了迫切要求。非晶含氢碳膜（a-C:H）在真空中具有极低摩擦系数（～0.004），但寿命非常有限。因此，本项目将系统研究a-C:H薄膜在不同真空环境中（真空度，N2、O2、H2分压，温度）的摩擦学行为，考察摩擦前后薄膜表面形貌、组成、化学状态等微观结构演变规律及其与真空摩擦学性能的关系，明确气体吸附、摩擦温升、接触应力等对真空摩擦磨损性能的影响，从内因（材料微观结构）和外因（环境因素、摩擦工况）两方面建立薄膜在高真空中的超润滑失效机理。在此基础上，利用非平衡磁控溅射和等离子体增强化学气相沉积相结合，将传统真空润滑材料如MoS2、WS2等与a-C:H薄膜通过多元复合，发展出在真空中具有极低摩擦（<0.005）、长寿命（>100万转）和高可靠性的新型超润滑薄膜，这对解决我国空间技术所面临的润滑问题具有重要理论意义和重大应用价值。

我国空间技术的发展，对真空中具有极低摩擦系数和长寿命的超润滑薄膜提出了迫切要求。非晶含氢碳膜（a-C:H）在真空中具有极低摩擦系数（～0.004），但寿命非常有限。因此，本项目从内因（材料微观结构）和外因（环境因素、摩擦工况）角度分别研究了a-C:H薄膜在真空环境下摩擦学性能的影响因素，系统研究了a-C:H薄膜在不同真空环境中（真空度，N2、O2、H2分压，温度）的摩擦学行为，考察摩擦前后薄膜表面形貌、组成、化学状态等微观结构演变规律及其与真空摩擦学性能的关系，发现除了氢含量，薄膜内应力、骨架结构等因素的重要作用机制，建立了非晶碳膜在真空环境下的动态摩擦失效机理。在此基础上，从表/界面、纳米多层/复合、非晶结构中程有序纳米结构设计三方面入手，改善薄膜内应力和微结构，探究出不同的非晶碳膜延寿途径，实现了非晶碳薄膜材料真空寿命跨数量级的提升，真空性能全面达到现役MoS2空间润滑薄膜GJB3032-97性能指标要求。而且相比于现役MoS2薄膜材料，其具有高硬度、大气存储稳定、大气高湿等其他环境润滑性能优异等优势。这将对解决我国空间技术所面临的润滑问题具有重要理论意义和重大应用价值。