Peng, J, Sergiienko, A, Mangolini, F et al. (3 more authors) (2016) Solid state magnetic resonance investigation of the thermally-induced structural evolution of silicon oxide-doped hydrogenated amorphous carbon. Carbon, 105. pp. 163-175. ISSN 0008-6223
Abstract
Due to their increased stability in extreme environments, relative to amorphous hydrogenated carbons (a-C:H), amorphous thin film silicon oxide-doped hydrogenated amorphous carbons (a-C:H:Si:O) are being commercially developed as solid lubricants and protective coatings. Although various properties of a-C:H:Si:O have been investigated, no definitive structure of a-C:H:Si:O has ever been proposed, nor has its thermally-induced structural evolution been thoroughly studied. The aim of this work is to better understand the structure of a-C:H:Si:O through solid-state nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopies. Deeper insights into the thermally-driven structural evolution are obtained by annealing a-C:H:Si:O between 50 °C and 300 °C under anaerobic conditions and taking NMR/EPR measurements after each step. EPR results show that the number of paramagnetic defects decreases by 70% with annealing at 300 °C. ¹H NMR shows the hydrogen concentration decreases with annealing temperature from 2 × 10²² g−¹, and then levels off at approximately 0.7 × 10²² g−¹ for anneals between 200 °C and 300 °C. The carbon–silicon–oxygen network exhibits some structural reorganization, seen directly as a slight increase in the sp²/sp³ ratio in the ¹³C NMR with annealing. These results combined with relaxation data are interpreted according to a two-component structure largely defined by differences in hydrogen and defect contents.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016 Published by Elsevier Ltd. This is an author produced version of a paper published in Carbon. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mechanical Engineering (Leeds) > Institute of Functional Surfaces (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 03 May 2016 09:41 |
Last Modified: | 14 Apr 2017 02:54 |
Published Version: | http://dx.doi.org/10.1016/j.carbon.2016.04.021 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.carbon.2016.04.021 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:99171 |