Carpick, RW

Hilbert, J

Lukes, JR

Mangolini, F

McClimon, JB

White Rose Research Online

This is a repository copy of In situ XPS and NEXAFS investigation of the thermally-induced structural evolution of advanced amorphous carbonbased surfaces.White Rose Research Online URL for this paper:http://eprints.whiterose.ac.uk/91834/Version: Accepted VersionProceedings Paper:Mangolini, F, McClimon, JB, Hilbert, J et al. (2 more authors) (2014) In situ XPS and NEXAFS investigation of the thermally-induced structural evolution of advanced amorphous carbonbased surfaces. In: Abstracts of Papers of the American Chemical Society. 248th ACS National Meeting and Exposition, 10-14 Aug 2014, San Francisco, CA,USA. American Chemical Society . eprints@whiterose.ac.ukhttps://eprints.whiterose.ac.uk/Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version - refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher’s website. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. In Situ XPS and NEXAFS Investigation of the Thermally-Induced Structural Evolution of Advanced Amorphous Carbon-Based Surfaces  Filippo Mangolini1, J. Brandon McClimon1, James Hilbert2, Jennifer R. Lukes2, Robert W. Carpick2  1 Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA 2 Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA   Silicon oxide-doped diamond-like carbon (SiOx-DLC) coatings are fully amorphous thin-film materials consisting of two interpenetrating networks, one being a hydrogenated amorphous carbon (a-C:H) network and the other a silica glass (SiOx) network. At temperatures above 150°C, pure a-C:H films undergo a rapid degradation that starts with the evolution of hydrogen and is followed by the conversion of sp3 bonds to sp2. However, SiOx-DLC exhibits much lower susceptibility to oxidative degradation, and much higher thermal stability compared to a-C:H. This makes SiOx-DLC an attractive material for many applications, including for the development of next generation hard disk drives, which require novel overcoat materials that are thermally stable up to temperatures above 500ºC. Even though it is well-established that SiOx-DLC possesses superior thermal stability and oxidation resistance relative to a-C:H, the scientific basis for this behavior is not understood. To investigate this, a combined in situ XPS and NEXAFS study was performed. Changes in the surface chemistry and bonding configuration of SiOx-DLC (e.g., silicon oxidation state, carbon hybridization state) could be accessed in situ at temperatures up to 450ºC. A novel methodology for processing NEXAFS spectra, which makes it possible to account for the presence of a carbonaceous contamination layer on an air-exposed material, was developed. This allowed quantitative evaluation of the carbon hybridization state in the film as a function of the annealing temperature. These experimental results could be well fit with a thermally activation-based model that describes the structural transformations occurring in vacuum in SiOx-DLC as a function of time and temperature. To determine the environmental dependence of the surface structural evolution of SiOx-DLC, the results of the in situ XPS/NEXAFS investigation were compared to those for SiOx-DLC samples heated in air, showing a strong effect of atmospheric oxygen.    

In situ XPS and NEXAFS investigation of the thermally-induced structural evolution of advanced amorphous carbonbased surfaces

https://eprints.whiterose.ac.uk/91834/1/Abstract_ACS_V11.pdf

In situ XPS and NEXAFS investigation of the thermally-induced structural evolution of advanced amorphous carbonbased surfaces

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