Li Ruiyun, Yang Xing, Li Jiacheng, Wang Yongfu, Ma Ming
Institute of Superlubricity Technology, Research Institute of Tsinghua University in Shenzhen, Shenzhen, 518057, China.
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou, 730000, China.
Nat Commun. 2024 Oct 24;15(1):9197. doi: 10.1038/s41467-024-53462-4.
Achieving solid superlubricity in high-humidity environments is of great practical importance yet remains challenging nowadays, due to the complex physicochemical roles of water and concomitant oxidation on solid surfaces. Here we report a facile way to access humidity-insensitive solid superlubricity (coefficient of friction 0.0035) without detectable wear and running-in at a humidity range of 2-80%. Inspired by the concept of structural superlubricity, this is achieved between Au-capped microscale graphite flake and graphene nanoflake-covered hydrogen-free amorphous carbon (GNC a-C). Such GNC a-C exhibits reduced pinning effects of water molecules and weak oxidation, which demonstrates stable structural superlubricity even after air exposure of the surfaces for 365 days. The manufacturability of such design enables the macroscopic scale-up of structural superlubricity, achieving the leap from 4 μm × 4 μm contact to 3 mm ball-supported contact with a wide range of materials. Our results suggest a strategy for the macroscale application of structural superlubricity under ambient condition.
在高湿度环境中实现稳定的超润滑具有重要的实际意义，但由于水在固体表面的复杂物理化学作用以及随之而来的氧化反应，目前仍然具有挑战性。在此，我们报告了一种简便的方法，可在2%-80%的湿度范围内实现对湿度不敏感的固体超润滑（摩擦系数为0.0035），且无明显磨损和磨合。受结构超润滑概念的启发，这种超润滑是在金包覆的微米级石墨薄片与覆盖有石墨烯纳米薄片的无氢非晶碳（GNC a-C）之间实现的。这种GNC a-C表现出降低的水分子钉扎效应和较弱的氧化作用，即使在表面暴露于空气中365天后仍能表现出稳定的结构超润滑。这种设计的可制造性能够实现结构超润滑的宏观放大，实现从4μm×4μm接触到3mm滚珠支撑接触的跨越，适用于多种材料。我们的结果为在环境条件下结构超润滑的宏观应用提供了一种策略。
