Liu, X., Iamvasant, C., Liu, C. et al. (2 more authors) (2016) CrCuAgN PVD nanocomposite coatings: Effects of annealing on coating morphology and nanostructure. Applied Surface Science, 392. pp. 732-746. ISSN 0169-4332
Abstract
CrCuAgN PVD nanocomposite coatings were produced using pulsed DC unbalanced magnetron sputtering. This investigation focuses on the effects of post-coat annealing on the surface morphology, phase composition and nanostructure of such coatings. In coatings with nitrogen contents up to 16 at.%, chromium exists as metallic Cr with N in supersaturated solid solution, even after 300 °C and 500 °C post-coat annealing. Annealing at 300 °C did not obviously change the phase composition of both nitrogen-free and nitrogen-containing coatings; however, 500 °C annealing resulted in significant transformation of the nitrogen-containing coatings. The formation of Ag aggregates relates to the (Cu + Ag)/Cr atomic ratio (threshold around 0.2), whereas the formation of Cu aggregates relates to the (Cu + Ag + N)/Cr atomic ratio (threshold around 0.5). The primary annealing-induced changes were reduced solubility of Cu, Ag and N in Cr, and the composition altering from a mixed ultra-fine nanocrystalline and partly amorphous phase constitution to a coarser, but still largely nanocrystalline structure. It was also found that, with sufficient Cu content (>12 at.%), annealing at a moderately high temperature (e.g. 500 °C) leads to transportation of both Cu and Ag (even at relatively low concentrations of Ag, ≤3 at.%) from inside the coating to the coating surface, which resulted in significant reductions in friction coefficient, by over 50% compared to that of the substrate (from 0.31 to 0.14 with a hemispherical diamond indenter, and from 0.83 to 0.40 with an alumina ball counterface, respectively). Results indicate that the addition of both Cu and Ag (in appropriate concentrations) to nitrogen-containing chromium is a viable strategy for the development of ‘self-replenishing’ silver-containing thin film architectures for temperature-dependent solid lubrication requirements or antimicrobial coating applications.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016 Elsevier. This is an author produced version of a paper subsequently published in Applied Surface Science. Uploaded in accordance with the publisher's self-archiving policy. Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/) |
Keywords: | Nanocomposite; PVD coatings; Annealing; Transportation; Phase transformation; Nanostructure |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) |
Funding Information: | Funder Grant number INNOVATE UK (TSB) 101005 (4708-44211) ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL (EPSRC) DT/F007183/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 17 Oct 2016 14:43 |
Last Modified: | 14 Sep 2017 05:01 |
Published Version: | http://dx.doi.org/10.1016/j.apsusc.2016.09.011 |
Status: | Published |
Publisher: | Elsevier |
Refereed: | Yes |
Identification Number: | 10.1016/j.apsusc.2016.09.011 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:105912 |