Pei Lulu, Chen Weiqi, Ju Pengfei, Zhou Hong, Xu Zhou, Ji Li, Ma Tianbao, Li Hongxuan, Liu Xiaohong, Zhou Huidi, Chen Jianmin
Key Laboratory of Science and Technology on Wear and Protection of Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
J Phys Chem Lett. 2021 Oct 28;12(42):10333-10338. doi: 10.1021/acs.jpclett.1c02841. Epub 2021 Oct 19.
A hydrogenated amorphous carbon (a-C:H) film shows an ultralow friction coefficient (COF, lower than 0.01); however, its wear life is short in vacuum, and the mechanisms are still not well-understood. This study demonstrates the vacuum tribological behaviors of the a-C:H film can be regulated by interfacial activity. The strong interfacial activity induced continuous transfer of carbon from the film to counterface, causing the formation of a porous transfer film and severe wear of the a-C:H film. Interestingly, weak interfacial activity is beneficial to form spherical-like carbon at the sliding interface, which shields the interaction of dangling bonds and contributes to lower COF and wear of film. Notably, the catalytic nature of Au induced perfect graphene nanoscrolls around Au nanoparticles at the sliding interface, achieving ultralong vacuum wear life. This Letter unifies the understanding of vacuum tribological properties of a-C:H film and provides new insight for prolonging the life of carbon films in vacuum.
氢化非晶碳（a-C:H）薄膜表现出超低摩擦系数（摩擦系数低于0.01）；然而，其在真空中的磨损寿命较短，且相关机制仍未得到很好的理解。本研究表明，a-C:H薄膜的真空摩擦学行为可通过界面活性来调节。强界面活性导致碳从薄膜持续转移到对偶表面，从而形成多孔转移膜并使a-C:H薄膜发生严重磨损。有趣的是，弱界面活性有利于在滑动界面形成球状碳，这屏蔽了悬空键的相互作用，有助于降低薄膜的摩擦系数和磨损。值得注意的是，金的催化性质在滑动界面诱导金纳米颗粒周围形成完美的石墨烯纳米卷轴，实现了超长的真空磨损寿命。本文统一了对a-C:H薄膜真空摩擦学性能的认识，并为延长碳薄膜在真空中的寿命提供了新的见解。
