Next Article in Journal / Special Issue
Tribology of Wire Arc Spray Coatings under the Influence of Regenerative Fuels
Previous Article in Journal
Electron Microscopy and Spectroscopy in the Analysis of Friction and Wear Mechanisms
Previous Article in Special Issue
The Running-in of Lubricated Metal-Metal Contacts—A Review on Ultra-Low Wear Systems
Open AccessArticle

Ultra-Low Friction on Tetrahedral Amorphous Diamond-Like Carbon (ta-C) Lubricated with Ethylene Glycol

Physics of Surfaces, Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Str. 16, D-64287 Darmstadt, Germany
Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Str. 10, D-64287 Darmstadt, Germany
BMW Group, D-80788 Munich, Germany
Institute for Surface and Thin Film Analysis (IFOS), Trippstadter Straße 120, D-67663 Kaiserslautern, Germany
Author to whom correspondence should be addressed.
Lubricants 2018, 6(3), 59;
Received: 23 May 2018 / Revised: 25 June 2018 / Accepted: 3 July 2018 / Published: 7 July 2018
(This article belongs to the Special Issue Applied Nanotribology)
PDF [5096 KB, uploaded 7 July 2018]


Lubricated tetrahedral amorphous carbon coatings can show a very complex tribological behavior. In particular, friction regimes with extremely low friction have been observed. In tribological experiments with a ta-C/steel friction pair that was lubricated with ethylene glycol, we observed a sudden and very strong decrease in the effective friction coefficient from 0.45 to 0.01 after running-in. By varying different components of the tribological system after this abrupt decrease we investigated the role of the counter-body, the lubricant and the coating. To investigate the surface chemistry, static time-of-flight secondary ion mass spectrometry (ToF-SIMS), dynamic secondary ion mass spectrometry (SIMS), and X-ray photoelectron spectroscopy (XPS) measurements were performed. Using deuterated lubricants, ToF-SIMS measurements allowed us to distinguish adsorption of hydrogen and hydroxyl-groups from the lubricant from the adsorption from the environment. Deuterated hydroxyl-groups from the lubricant adsorbed to the surface during the experiment. In particular, more adsorbed deuterated hydroxyl-groups were detected prior to the sudden decrease in the friction coefficient. Thus, the sudden decrease in the coefficient of friction was most likely caused by an interplay between the lubricant, the ta-C coating and the counter-body which lead to the formation of transfer and adsorption layers. View Full-Text
Keywords: diamond-like carbon; ToF-SIMS; XPS; coefficient of friction; ethane-1,2-diol; ta-C diamond-like carbon; ToF-SIMS; XPS; coefficient of friction; ethane-1,2-diol; ta-C

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).

Share & Cite This Article

MDPI and ACS Style

Bachmann, S.; Schulze, M.; Krell, L.; Merz, R.; Wahl, M.; Stark, R.W. Ultra-Low Friction on Tetrahedral Amorphous Diamond-Like Carbon (ta-C) Lubricated with Ethylene Glycol. Lubricants 2018, 6, 59.

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



[Return to top]
Lubricants EISSN 2075-4442 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top