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Tribology Letters

, Volume 55, Issue 1, pp 1–13 | Cite as

Microstructure Evolution and Enhanced Tribological Properties of Cu-Doped WS2 Films

  • Shusheng Xu
  • Xiaoming Gao
  • Ming Hu
  • Desheng Wang
  • Dong Jiang
  • Jiayi Sun
  • Feng Zhou
  • Lijun WengEmail author
  • Weimin LiuEmail author
Original Paper

Abstract

To improve the tribological properties of WS2 film both in vacuum and in humid air conditions, its microstructure was optimized by doping different concentrations of Cu via radio frequency co-sputtering method. The film microstructure and composition were investigated by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, grazing incidence X-ray diffraction and high-resolution transmission electron microscopy. It was verified that Cu was presented in amorphous phase in the WS2 matrix and could also induce amorphization and densification of the composite films gradually. The film microstructure changed from coarse columnar platelet structure at low Cu content (0–5.8 at.%) to transition structure with two separate layers at increased Cu content (11.5–16.2 at.%) and to a featureless structure at high Cu content (above 24.4 at.%). The mechanical and tribological properties of films were evaluated using the scratch tester and ball-on-disk tribometer, respectively. It was found that the incorporation of a suitable content of Cu dopant could significantly improve the film toughness, but excess amount of Cu dopant lead to high brittleness. All the composite films exhibited much lower wear rate and longer wear life than those of pure WS2 film both in vacuum and in humid air conditions. The wear mechanisms were proposed after correlating the mechanical performance with film microstructure.

Keywords

WS2 film Cu dopant Microstructure Mechanical/tribological properties 

Notes

Acknowledgments

The authors gratefully acknowledged the National Key Basic Research Program of China (973) (Grant No. 2013CB632300) and National Natural Science Foundation of China (Grant No. 51305427) for financial support.

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Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  • Shusheng Xu
    • 1
    • 2
  • Xiaoming Gao
    • 1
  • Ming Hu
    • 1
  • Desheng Wang
    • 1
  • Dong Jiang
    • 1
  • Jiayi Sun
    • 1
  • Feng Zhou
    • 1
  • Lijun Weng
    • 1
    Email author
  • Weimin Liu
    • 1
    Email author
  1. 1.State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhouPeople’s Republic of China
  2. 2.University of Chinese Academy of SciencesBeijingPeople’s Republic of China

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