摘要
Diamond-like carbon(DLC)film has been developed as an extremely effective lubricant to reduce energy dissipation;however,most films should undergo running-in to achieve a super-low friction state.In this study,the running-in behaviors of an H–DLC/Al_(2)O_(3) pair were investigated through a controllable single-asperity contact study using an atomic force microscope.This study presents direct evidence that illustrates the role of transfer layer formation and oxide layer removal in the friction reduction during running-in.After 200 sliding cycles,a thin transfer layer was formed on the Al2O3 tip.Compared with a clean tip,this modified tip showed a significantly lower adhesion force and friction force on the original H–DLC film,which confirmed the contribution of the transfer layer formation in the friction reduction during running-in.It was also found that the friction coefficient of the H–DLC/Al_(2)O_(3) pair decreased linearly as the oxygen concentration of the H–DLC substrate surface decreased.This phenomenon can be explained by a change in the contact surface from an oxygen termination with strong hydrogen bond interactions to a hydrogen termination with weak van der Waals interactions.These results provide new insights that quantitatively reveal the running-in mechanism at the nanoscale,which may help with the design optimization of DLC films for different environmental applications.
出处
《Friction》
SCIE
EI
CAS
CSCD
2021年第6期1464-1473,共10页
摩擦（英文版）
基金
The authors are grateful for the financial support from the National Natural Science Foundation of China(51875486 and 51991373)
Sichuan Science and Technology Program(2019YFH0098).
