Differentiating the tribological performance of hydrogenated and hydrogen-free DLC coatings

Helena Ronkainen (Corresponding Author), Simo Varjus, Jari Koskinen, Kenneth Holmberg

Research output: Contribution to journalArticleScientificpeer-review

148 Citations (Scopus)

Abstract

Diamond-like carbon (DLC) coatings cover a wide range of different types of carbon-based coatings, which generally have properties such as low friction and high wear resistance. DLC films can be divided into two major groups based on their hydrogen content, namely hydrogenated and hydrogen-free carbon coatings. This presentation describes the research work on amorphous hydrogenated carbon films (a-C:H) and hydrogen-free tetrahedral amorphous carbon films (ta-C). These coating types offer low friction performance and good wear resistance, but they also have some dissimilarities in the friction and wear properties due to their different hydrogen content and microstructure.

The a-C:H films deposited for this study were produced by the rf plasma deposition technique and the ta-C films by the pulsed vacuum arc technique. The tribological performance of the a-C:H and ta-C coatings was evaluated by pin-on-disc tests carried out in normal atmosphere. Selected coatings were also evaluated in dry atmosphere. The wear resistance of the ta-C films was higher compared to the a-C:H films, but the ta-C films caused higher wear of the counterpart. The increase in normal load and sliding velocity decreased the friction coefficient of the a-C:H coating against the steel and alumina counter-face, whereas the ta-C coating showed more stable friction performance. The micro-Raman studies showed clear graphite formation for the a-C:H film, whereas the graphite formation on the ta-C film was not so evident. In dry conditions the ta-C had a high friction coefficient, which could be reduced by doping the film with hydrogen. The results show that the hydrogen content together with graphitisation plays an important role in the friction performance of DLC films.

Original languageEnglish
Pages (from-to)260-266
Number of pages7
JournalWear
Volume249
Issue number3-4
DOIs
Publication statusPublished - 2001
MoE publication typeA1 Journal article-refereed
Event9th Nordic Symposium on Tribology: NORDTRIB 2000 - Porvoo, Finland
Duration: 11 Jun 200014 Jun 2000

Fingerprint

Diamond
Carbon films
Amorphous carbon
Amorphous films
Hydrogen
Diamonds
Carbon
diamonds
coatings
Coatings
carbon
Friction
hydrogen
Wear resistance
Diamond like carbon films
Graphite
friction
Wear of materials
wear resistance
Plasma deposition

Keywords

  • DLC coatings
  • tribology
  • a-C:H
  • ta-C

Cite this

Ronkainen, Helena ; Varjus, Simo ; Koskinen, Jari ; Holmberg, Kenneth. / Differentiating the tribological performance of hydrogenated and hydrogen-free DLC coatings. In: Wear. 2001 ; Vol. 249, No. 3-4. pp. 260-266.
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Differentiating the tribological performance of hydrogenated and hydrogen-free DLC coatings. / Ronkainen, Helena (Corresponding Author); Varjus, Simo; Koskinen, Jari; Holmberg, Kenneth.

In: Wear, Vol. 249, No. 3-4, 2001, p. 260-266.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Differentiating the tribological performance of hydrogenated and hydrogen-free DLC coatings

AU - Ronkainen, Helena

AU - Varjus, Simo

AU - Koskinen, Jari

AU - Holmberg, Kenneth

PY - 2001

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N2 - Diamond-like carbon (DLC) coatings cover a wide range of different types of carbon-based coatings, which generally have properties such as low friction and high wear resistance. DLC films can be divided into two major groups based on their hydrogen content, namely hydrogenated and hydrogen-free carbon coatings. This presentation describes the research work on amorphous hydrogenated carbon films (a-C:H) and hydrogen-free tetrahedral amorphous carbon films (ta-C). These coating types offer low friction performance and good wear resistance, but they also have some dissimilarities in the friction and wear properties due to their different hydrogen content and microstructure.The a-C:H films deposited for this study were produced by the rf plasma deposition technique and the ta-C films by the pulsed vacuum arc technique. The tribological performance of the a-C:H and ta-C coatings was evaluated by pin-on-disc tests carried out in normal atmosphere. Selected coatings were also evaluated in dry atmosphere. The wear resistance of the ta-C films was higher compared to the a-C:H films, but the ta-C films caused higher wear of the counterpart. The increase in normal load and sliding velocity decreased the friction coefficient of the a-C:H coating against the steel and alumina counter-face, whereas the ta-C coating showed more stable friction performance. The micro-Raman studies showed clear graphite formation for the a-C:H film, whereas the graphite formation on the ta-C film was not so evident. In dry conditions the ta-C had a high friction coefficient, which could be reduced by doping the film with hydrogen. The results show that the hydrogen content together with graphitisation plays an important role in the friction performance of DLC films.

AB - Diamond-like carbon (DLC) coatings cover a wide range of different types of carbon-based coatings, which generally have properties such as low friction and high wear resistance. DLC films can be divided into two major groups based on their hydrogen content, namely hydrogenated and hydrogen-free carbon coatings. This presentation describes the research work on amorphous hydrogenated carbon films (a-C:H) and hydrogen-free tetrahedral amorphous carbon films (ta-C). These coating types offer low friction performance and good wear resistance, but they also have some dissimilarities in the friction and wear properties due to their different hydrogen content and microstructure.The a-C:H films deposited for this study were produced by the rf plasma deposition technique and the ta-C films by the pulsed vacuum arc technique. The tribological performance of the a-C:H and ta-C coatings was evaluated by pin-on-disc tests carried out in normal atmosphere. Selected coatings were also evaluated in dry atmosphere. The wear resistance of the ta-C films was higher compared to the a-C:H films, but the ta-C films caused higher wear of the counterpart. The increase in normal load and sliding velocity decreased the friction coefficient of the a-C:H coating against the steel and alumina counter-face, whereas the ta-C coating showed more stable friction performance. The micro-Raman studies showed clear graphite formation for the a-C:H film, whereas the graphite formation on the ta-C film was not so evident. In dry conditions the ta-C had a high friction coefficient, which could be reduced by doping the film with hydrogen. The results show that the hydrogen content together with graphitisation plays an important role in the friction performance of DLC films.

KW - DLC coatings

KW - tribology

KW - a-C:H

KW - ta-C

U2 - 10.1016/S0043-1648(01)00558-0

DO - 10.1016/S0043-1648(01)00558-0

M3 - Article

VL - 249

SP - 260

EP - 266

JO - Wear

JF - Wear

SN - 0043-1648

IS - 3-4

ER -