The hardness of porous nanocrystalline Co-Ni electrodeposits
The hardness of porous nanocrystalline Co-Ni electrodeposits
The Hall-Petch relationship can fail when the grain size is below a critical value of tens of nanometres. This occurs particularly for coatings having porous surfaces. In this study, electrodeposited nanostructured Co-Ni coatings from four different nickel electroplating baths having grain sizes in the range of 11–23 nm have been investigated. The finest grain size, approximately 11 nm, was obtained from a coating developed from the nickel sulphate bath. The Co-Ni coatings have a mixed face centred cubic and hexagonal close-packed structures with varying surface morphologies and different porosities. A cluster-pore mixture model has been proposed by considering no contribution from pores to the hardness. As the porosity effect was taken into consideration, the calculated pore-free hardness is in agreement with the ordinary Hall-Petch relationship even when the grain size is reduced to 11 nm for the Co-Ni coatings with 77±2 at% cobalt. The present model was applied to other porous nanocrystalline coatings, and the Hall-Petch relationship was maintained.
hardness, nanocrystalline, hall-petch relationship, porosity, Co-Ni
1187-1192
Ma, Chao
dda2ade4-9c21-4689-882c-1dfa8c63284c
Wang, Shuncai
8a390e2d-6552-4c7c-a88f-25bf9d6986a6
Wood, Robert J.K.
d9523d31-41a8-459a-8831-70e29ffe8a73
Zekonyte, Jurgita
c40df725-5ce3-4692-b638-bbb4d847b5ea
Luo, Quanshun
afd089fe-1e40-467c-8341-f0331cf7fc21
Walsh, Frank
309528e7-062e-439b-af40-9309bc91efb2
November 2013
Ma, Chao
dda2ade4-9c21-4689-882c-1dfa8c63284c
Wang, Shuncai
8a390e2d-6552-4c7c-a88f-25bf9d6986a6
Wood, Robert J.K.
d9523d31-41a8-459a-8831-70e29ffe8a73
Zekonyte, Jurgita
c40df725-5ce3-4692-b638-bbb4d847b5ea
Luo, Quanshun
afd089fe-1e40-467c-8341-f0331cf7fc21
Walsh, Frank
309528e7-062e-439b-af40-9309bc91efb2
Ma, Chao, Wang, Shuncai, Wood, Robert J.K., Zekonyte, Jurgita, Luo, Quanshun and Walsh, Frank
(2013)
The hardness of porous nanocrystalline Co-Ni electrodeposits.
Metals and Materials International, 19 (6), .
(doi:10.1007/s12540-013-6006-y).
Abstract
The Hall-Petch relationship can fail when the grain size is below a critical value of tens of nanometres. This occurs particularly for coatings having porous surfaces. In this study, electrodeposited nanostructured Co-Ni coatings from four different nickel electroplating baths having grain sizes in the range of 11–23 nm have been investigated. The finest grain size, approximately 11 nm, was obtained from a coating developed from the nickel sulphate bath. The Co-Ni coatings have a mixed face centred cubic and hexagonal close-packed structures with varying surface morphologies and different porosities. A cluster-pore mixture model has been proposed by considering no contribution from pores to the hardness. As the porosity effect was taken into consideration, the calculated pore-free hardness is in agreement with the ordinary Hall-Petch relationship even when the grain size is reduced to 11 nm for the Co-Ni coatings with 77±2 at% cobalt. The present model was applied to other porous nanocrystalline coatings, and the Hall-Petch relationship was maintained.
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Published date: November 2013
Keywords:
hardness, nanocrystalline, hall-petch relationship, porosity, Co-Ni
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nCATS Group
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Local EPrints ID: 354022
URI: http://eprints.soton.ac.uk/id/eprint/354022
ISSN: 1598-9623
PURE UUID: 227d13f0-b9eb-40a3-8343-27203f61a5b1
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Date deposited: 28 Jun 2013 09:17
Last modified: 15 Mar 2024 02:47
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Author:
Chao Ma
Author:
Jurgita Zekonyte
Author:
Quanshun Luo
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