Surface structure of hydrogenated diamond-like carbon

Origin of run-in behavior prior to superlubricious interfacial shear

Ala A. Al-Azizi, Osman Eryilmaz, Ali Erdemir, Seong Kim

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The oxidized layers at the surface of hydrogenated diamond-like carbon (H-DLC) were studied with X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure, and Raman spectroscopy. The structure of these layers was correlated with the friction and wear behavior observed on H-DLC. H-DLC is well-known for its ultralow friction in inert environments, but the steady superlubricious state is always preceded by a run-in period with a high friction. It was hypothesized that the run-in period is related to the surface oxide layer formed naturally upon exposure of the sample to air. To test this hypothesis, thermal oxide layers were grown, and their structures were analyzed and compared with the native oxide layer on a pristine sample. It was found that the Raman spectra of the surface oxide layers of H-DLC have higher D/G band ratio than the bulk, indicating a larger amount of aromatic clusters compared to the bulk film. Thick oxide layers grown at 300 °C showed a run-in friction behavior that resembled the friction of graphite. The run-in periods were found to become longer when the thickness of the oxide layers increased, indicating that the run-in behavior of H-DLC is attributed to the removal of the surface oxide layers.

Original languageEnglish (US)
Pages (from-to)1711-1721
Number of pages11
JournalLangmuir
Volume31
Issue number5
DOIs
StatePublished - Feb 10 2015

Fingerprint

Diamond
Surface structure
Oxides
Diamonds
Carbon
diamonds
shear
carbon
Friction
oxides
friction
X ray absorption near edge structure spectroscopy
Graphite
Raman spectroscopy
Raman scattering
X ray photoelectron spectroscopy
Wear of materials
x rays
graphite
fine structure

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

Cite this

Al-Azizi, Ala A. ; Eryilmaz, Osman ; Erdemir, Ali ; Kim, Seong. / Surface structure of hydrogenated diamond-like carbon : Origin of run-in behavior prior to superlubricious interfacial shear. In: Langmuir. 2015 ; Vol. 31, No. 5. pp. 1711-1721.
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Surface structure of hydrogenated diamond-like carbon : Origin of run-in behavior prior to superlubricious interfacial shear. / Al-Azizi, Ala A.; Eryilmaz, Osman; Erdemir, Ali; Kim, Seong.

In: Langmuir, Vol. 31, No. 5, 10.02.2015, p. 1711-1721.

Research output: Contribution to journalArticle

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