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Zhang Y, Li J, Wang Y, Nie J, Wang C, Tian K, Ma M. Loading Mode-Induced Enhancement in Friction for Microscale Graphite/Hexagonal Boron Nitride Heterojunction. ACS APPLIED MATERIALS & INTERFACES 2024; 16:5308-5315. [PMID: 38235683 DOI: 10.1021/acsami.3c16962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Classical friction laws traditionally assume that the friction between solid pairs remains constant with a given normal load. However, our study has unveiled a remarkable deviation from conventional wisdom. In this paper, we discovered that altering the loading mode of micro graphite flakes led to significant changes in the lateral friction under identical normal loads. By adding a cap onto a single graphite flake to disperse the normal load applied by an atomic force microscope (AFM) tip, we were able to distribute the concentrated force. Astonishingly, our results demonstrated a notable 4-7 times increase in friction as a consequence of load dispersion. Finite element analysis (FEA) further confirmed that the increase in compressive stress at the edges of the graphite flake, resulting from load dispersion, led to a significant increase in friction. This study underscores the critical role of the loading mode in microscale friction dynamics, challenging the prevailing notion that friction remains static with a given normal force. Importantly, our research sheds light on the potential for achieving macroscale structural superlubricity (SSL) by assembling microscale SSL graphite flakes by using a larger cap.
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Affiliation(s)
- Yize Zhang
- State Key Laboratory of Tribology in Advanced Equipment & Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
- Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China
| | - Jiacheng Li
- State Key Laboratory of Tribology in Advanced Equipment & Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
| | - Yiran Wang
- State Key Laboratory of Tribology in Advanced Equipment & Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
| | - Jinhui Nie
- Institute of Superlubricity Technology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
| | - Chen Wang
- Laboratory of Advanced Energy Storage Materials & devices, Center for Advanced Materials & Biotechnology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
| | - Kaiwen Tian
- Institute of Superlubricity Technology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
| | - Ming Ma
- State Key Laboratory of Tribology in Advanced Equipment & Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
- Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China
- Institute of Superlubricity Technology, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057, China
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