AFM probe with the U-shaped cross-sectional cantilever for measuring the ultra-low coefficient of friction of 10^(–6)  

作　　者：Yushan CHEN Liang JIANG Linmao QIAN 

机构地区：[1]Tribology Research Institute,State Key Laboratory of Traction Power,Southwest Jiaotong University,Chengdu 610031,China

出　　处：《Friction》2024年第8期1707-1715,F0004,共10页摩擦（英文版）

基　　金：the financial support by the National Key R&D Program of China(2020YFA0711001);the National Natural Science Foundation of China(51975488,51991373,and 52235004).

摘　　要：Accurately measuring the coefficient of friction(COF)is the fundamental prerequisite of superlubricity research.This study aimed to reduce the COF measurement resolutionΔμof atomic force microscopy(AFM).Based on the theoretical model,a distinctive strategy was adopted to reduceΔμby optimizing the cantilever’s cross-section of the AFM probe,inspired by civil engineering.Δμcan be reduced by decreasing the width of the horizontal side wR and the wall thickness t and increasing the width of the vertical side wH.Moreover,the I-shape demonstrates the highest reduction inΔμ,followed by the U-shape.Considering the processability,the AFM probe with the U-shaped cross-sectional cantilever was investigated further,and the dimensions are 35μm wR,3.5μm wH,0.5μm t,50μm l(cantilever length),and 23μm htip(tip height).The finite element analysis results confirm its reliability.After being fabricated and calibrated,the AFM probe achieves the minimalΔμof 1.9×10^(–6)under the maximum normal force so far.Additionally,the friction detection capability of the fabricated AFM probe improves by 78 times compared to the commercial tipless-force modulation mode(TL-FM)AFM probe with the conventional solid rectangular cross-sectional cantilever.This study provides a powerful tool for measuring 10^(–6)COF.

关 键 词：atomic force microscopy SUPERLUBRICITY coefficient of friction PROBE CANTILEVER 

分 类 号：TH117[机械工程—机械设计及理论]