100 km wear-free sliding achieved by microscale superlubric graphite/DLC heterojunctions under ambient conditions  

作　　者：Deli Peng Jin Wang Haiyang Jiang Shuji Zhao Zhanghui Wu Kaiwen Tian Ming Ma Quanshui Zheng 

机构地区：[1]Department of Engineeiing Mechanics,Tsinghua University,Beijing 100084,China [2]Center for Nano and Micro Mechanics,Tsinghua University,Beijing 100084,China [3]Institute of Superlubricity Technology,Research Institute of Tsinghua University in Shenzhen,Shenzhen 518057,China [4]State Key Laboratory of Tribology,Tsinghua University,Beijing 100084,China [5]Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China

出　　处：《National Science Review》2022年第1期12-19,共8页国家科学评论（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(11890671 and 51961145304 to Q.Z.,11890673 and 11772168 to M.M.).

摘　　要：Wear-free sliding between two contacted solid surfaces is the ultimate goal in the effort to extend the lifetime of mechanical devices,especially when it comes to inventing new types of micro-ele ctromechanical systems where wear is often a major obstacle.Here we report experimental observations of wear-free sliding for a micrometer-sized graphite flake on a diamond-like-carbon(DLC) surface under ambient conditions with speeds up to 2.5 m/s,and over a distance of 100 km.The coefficient of friction(COF) between the microscale graphite flake,a van der Waals(vdW) layered material and DLC,a non-vdW-layered material,is measured to be of the order of 10^(-3),which belongs to the superlubric regime.Such ultra-low COFs are also demonstrated for a microscale graphite flake sliding on six other kinds of non-vdW-layered materials with sub-nanometer roughness.With a synergistic analysis approach,we reve al the underlying mechanism to be the combination of interfacial vdW interaction,atomic-smooth interfaces and the low normal stiffness of the graphite flake.These features guarantee a persistent full contact of the interface with weak interaction,which contributes to the ultra-low COFs.Together with the extremely high in-plane strength of graphene,wear-free sliding is achieve d.Our results broaden the scope of superlubricity and promote its wider application in the future.

关 键 词：structural superlubricity wear-free MICROSCALE GRAPHITE DLC 

分 类 号：O313.5[理学—一般力学与力学基础] TH117.1[理学—力学]