Wang Yongfu, Yang Xing, Liang Huiting, Zhao Jun, Zhang Junyan
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou, 730000, China.
Key Laboratory of Science and Technology on Wear and Protection of Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.
Adv Sci (Weinh). 2024 May;11(19):e2309701. doi: 10.1002/advs.202309701. Epub 2024 Mar 14.
Interlayer incommensurateness slippage is an excellent pathway to realize superlubricity of van der Waals materials; however, it is instable and heavily depends on twisted angle and super-smooth substrate which pose great challenges for the practical application of superlubricity. Here, macroscale superlubricity (0.001) is reported on countless nanoscale graphene moiré structure (GMS)-assembled surface via counterface hydrogen (H) modulation. The GMS-assembled surface is formed on grinding balls via sphere-triggered strain engineering. By the H modulation of counterface diamond-like carbon (25 at.% H), the wear of GMS-assembled surface is significantly reduced and a steadily superlubric sliding interface between them is achieved, based on assembly face charge depletion and H-induced assembly edge weakening. Furthermore, the superlubricity between GMS-assembled and DLC25 surfaces holds true in wide ranges of normal load (7-11 N), sliding velocity (0.5-27 cm s), contact area (0.4×10-3.7×10 µm), and contact pressure (0.19-1.82 GPa). Atomistic simulations confirm the preferential formation of GMS on a sphere, and demonstrate the superlubricity on GMS-assembled surface via counterface H modulation. The results provide an efficient tribo-pairing strategy to achieve robust superlubricity, which is of significance for the engineering application of superlubricity.
层间失配滑移是实现范德华材料超润滑性的一条极佳途径；然而，它并不稳定，且严重依赖于扭曲角和超光滑基底，这给超润滑性的实际应用带来了巨大挑战。在此，通过对偶面氢（H）调制，在无数纳米级石墨烯莫尔结构（GMS）组装表面上实现了宏观尺度的超润滑性（0.001）。GMS组装表面通过球体触发应变工程在磨球上形成。通过对偶面类金刚石碳（含25原子%的H）的H调制，基于组装面电荷耗尽和H诱导的组装边缘弱化，GMS组装表面的磨损显著降低，并在它们之间实现了稳定的超润滑滑动界面。此外，GMS组装表面与DLC25表面之间的超润滑性在较宽的法向载荷（7 - 11 N）、滑动速度（0.5 - 27 cm/s）、接触面积（0.4×10 - 3.7×10 µm）和接触压力（0.19 - 1.82 GPa）范围内均成立。原子模拟证实了GMS在球体上的优先形成，并通过对偶面H调制证明了GMS组装表面的超润滑性。这些结果提供了一种实现稳健超润滑性的有效摩擦副配对策略，这对超润滑性的工程应用具有重要意义。
