Low frictions of self-mated CNx coatings in dry and humid inert gas environments

Pengfei Wang, Koshi Adachi

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

The friction behavior of CNx coated Si3N4 disk sliding against CNx coated Si3N4 ball (denoted as CNx/CNx) in dry and humid inert gas environments (i.e. nitrogen, argon, and helium) is investigated in this study. The sliding contact of self-mated CNx coatings has been realized thanks to the promising two-step ball-on-disk friction test, where the rubbed Si3N4 ball in the running-in stage (step 1) is replaced by a new CNx coated Si3N4 ball in the subsequent stage (step 2). As a result, friction coefficients of less than 0.05 are obtained for self-mated CNx coatings in all three dry inert gas environments with relative humidity under 5%RH. Moreover, friction coefficients of less than 0.10 are obtained for the sliding contact of CNx/CNx in inert gas environments with relative humidity of larger than 35%RH. Especially, the lowest friction coefficient of 0.020 is achieved in the nitrogen gas environment with relative humidity of 37%RH. Furthermore, the sliding contact of self-mated CNx coatings survives after friction tests in humid nitrogen and argon gas environments. The low frictional performance and low sensitivity of friction to water vapor for the self-mated CNx coatings in inert gas environments are mainly attributed to the formation of a sp2 rich carbon tribo-layer on the mating surface. The pronounced frictional performance of self-mated CNx coatings has made them good candidates for the demanding industrial applications.

Original languageEnglish
Pages (from-to)1137-1144
Number of pages8
JournalSurface and Coatings Technology
Volume258
DOIs
Publication statusPublished - 2014 Nov 15

Keywords

  • Carbon nitride
  • Carbon tribo-layer
  • Friction behavior
  • Inert gas
  • Tribo-film

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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