Next Article in Journal
Ti–Zr–Si–Nb Nanocrystalline Alloys and Metallic Glasses: Assessment on the Structure, Thermal Stability, Corrosion and Mechanical Properties
Previous Article in Journal
Experimental Verification of Isotropic and Anisotropic Anhysteretic Magnetization Models
Article Menu
Issue 9 (May-1) cover image

Export Article

Open AccessArticle

Key Role of Transfer Layer in Load Dependence of Friction on Hydrogenated Diamond-Like Carbon Films in Humid Air and Vacuum

1
Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
2
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
3
Beijing Key Laboratory of Long-life Technology of Precise Rotation and Transmission Mechanisms, Beijing Institute of Control Engineering, Beijing 100094, China
*
Authors to whom correspondence should be addressed.
Materials 2019, 12(9), 1550; https://doi.org/10.3390/ma12091550
Received: 9 March 2019 / Revised: 24 April 2019 / Accepted: 9 May 2019 / Published: 12 May 2019
  |  
PDF [3541 KB, uploaded 12 May 2019]
  |  

Abstract

The friction of hydrogenated diamond-like carbon (H-DLC) films was evaluated under the controlled environments of humid air and vacuum by varying the applied load. In humid air, there is a threshold applied load below which no obvious friction drop occurs and above which the friction decreases to a relatively low level following the running-in process. By contrast, superlubricity can be realized at low applied loads but easily fails at high applied loads under vacuum conditions. Further analysis indicates that the graphitization of the sliding H-DLC surface has a negligible contribution to the sharp drop of friction during the running-in process under both humid air and vacuum conditions. The low friction in humid air and the superlow friction in vacuum are mainly attributed to the formation and stability of the transfer layer on the counterface, which depend on the load and surrounding environment. These results can help us understand the low-friction mechanism of H-DLC film and define optimized working conditions in practical applications, in which the transfer layer can be maintained for a long time under low applied load conditions in vacuum, whereas a high load can benefit the formation of the transfer layer in humid air. View Full-Text
Keywords: hydrogenated DLC film; superlubricity; environment dependence; transfer layer; normal load hydrogenated DLC film; superlubricity; environment dependence; transfer layer; normal load
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Liu, Y.; Chen, L.; Zhang, B.; Cao, Z.; Shi, P.; Peng, Y.; Zhou, N.; Zhang, J.; Qian, L. Key Role of Transfer Layer in Load Dependence of Friction on Hydrogenated Diamond-Like Carbon Films in Humid Air and Vacuum. Materials 2019, 12, 1550.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Materials EISSN 1996-1944 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top