Soltanahmadi, S, Charpentier, T, Nedelcu, I et al. (7 more authors) (2019) Surface Fatigue Behaviour of a WC/aC:H Thin-Film and the Tribochemical Impact of Zinc Dialkyldithiophosphate. ACS Applied Materials & Interfaces, 11 (44). pp. 41676-41687. ISSN 1944-8244
Abstract
In wind turbine gearboxes, (near-)surface initiated fatigue is attributed to be the primary failure mechanism. In this work, the surface fatigue of a hydrogenated tungsten carbide/amorphous carbon (WC/aC:H) thin-film was tested under severe cyclic tribo-contact using PolyAlphaOlefin (PAO) and PAO + Zinc DialkylDithioPhosphate (ZDDP) lubricants. The film was characterised in terms of its structure and chemistry using X-ray diffraction, analytical Transmission Electron Microscopy (TEM) including Electron Energy Loss Spectroscopy (EELS), as well as X-ray Photoelectron Spectroscopy (XPS). The multilayer carbon thin-film exhibited promising surface fatigue performance showing a slight change in the hybridization state of the aC:H matrix. Dehydrogenation of the thin-film and subsequent transformation of cleaved C-H bonds to non planar sp2 carbon rings were inferred from EELS and XPS results. Whilst tribo-induced changes to the aC:H matrix were not influenced by a nanometer-thick ZDDP reaction-film, the rate of oxidation of WC and its oxidation state were affected. Whilst accelerating surface fatigue on a steel surface, the ZDDP-tribofilm protected the WC/aC:H film from surface fatigue. In contrast to the formation of polyphosphates from ZDDP molecules on steel surfaces, it appeared that on the WC/aC:H thin film surface ZDDP molecules decompose to ZnO suppressing the oxidative degradation of WC.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 American Chemical Society. This is an author produced version of a journal article published in ACS Applied Materials & Interfaces. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Carbon thin-film, Tungsten carbide carbon coating, Tribochemistry, Micropitting, Surface fatigue, ZDDP, non-planar carbon ring, dehydrogenation |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mechanical Engineering (Leeds) > Institute of Functional Surfaces (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) The University of Leeds > Faculty of Environment (Leeds) > School of Food Science and Nutrition (Leeds) > FSN Colloids and Food Processing (Leeds) |
Funding Information: | Funder Grant number EPSRC (Engineering and Physical Sciences Research Council) EP/M028143/1 EPSRC (Engineering and Physical Sciences Research Council) EP/P00122X/1 EPSRC (Engineering and Physical Sciences Research Council) EP/R001766/1 EPSRC (Engineering and Physical Sciences Research Council) EP/R02524X/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 18 Oct 2019 12:16 |
Last Modified: | 20 Jun 2021 08:38 |
Status: | Published |
Publisher: | American Chemical Society |
Identification Number: | 10.1021/acsami.9b14669 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:152265 |