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Wettability of hierarchically-textured ceramic coatings produced by suspension HVOF spraying

Wettability of hierarchically-textured ceramic coatings produced by suspension HVOF spraying
Wettability of hierarchically-textured ceramic coatings produced by suspension HVOF spraying
A novel but simple path for the preparation of superhydrophobic and superhydrophilic coatings has been demonstrated via a recently developed technology, namely Suspension High Velocity Oxy-Fuel spraying. Potential uses for robust superhydrophobic coatings include antifouling applications such as aeroplane wings, ship hulls, offshore wind turbine blades, or the above-deck structures on ice breaker vessels. Several fabrication techniques have been reported for preparing inorganic superhydrophobic surfaces, but existing coatings either lack the necessary robustness for engineering applications and/or their deposition methods are not suitable for industrial scale-up. In this work, the industrially established HVOF coating process was adapted to use a liquid suspension of commercially available nano-particles (Titania — TiO2, and hexagonal boron nitride — h-BN) as feedstock to produce nanostructured suspension HVOF TiO2/h-BN coatings for the first time on stainless steel. Results indicate that agglomerates in the nano-feedstock can be dispersed by h-BN due to poor mutual wettability between h-BN and molten TiO2. It also inhibits the anatase-to-rutile transformation of TiO2 during coating deposition by inhibiting sintering of TiO2 in the HVOF flame. The resultant coating becomes superhydrophobic when the addition of h-BN reaches 10 wt.% due to the presence of hierarchical nano-texture on the surface. The superhydrophobicity (contact angle of 163-170º) is maintained over a long period of time (>13 months, test still ongoing) and remains stable after exposure to light and tape test. A potential route for industrial preparation of robust water-repellent coatings is therefore highlighted by the study.
2050-7488
1-12
Zhang, F.
396ca776-f0e6-4750-974a-6ba3f9c78a41
Robinson, B.
d526cb99-a179-4ec2-b21d-935663368a6e
Villiers-Loverlock, H.
a705563f-e329-43ef-9093-83919eb62d38
Wood, R.J.K.
d9523d31-41a8-459a-8831-70e29ffe8a73
Wang, S.C.
8a390e2d-6552-4c7c-a88f-25bf9d6986a6
Zhang, F.
396ca776-f0e6-4750-974a-6ba3f9c78a41
Robinson, B.
d526cb99-a179-4ec2-b21d-935663368a6e
Villiers-Loverlock, H.
a705563f-e329-43ef-9093-83919eb62d38
Wood, R.J.K.
d9523d31-41a8-459a-8831-70e29ffe8a73
Wang, S.C.
8a390e2d-6552-4c7c-a88f-25bf9d6986a6

Zhang, F., Robinson, B., Villiers-Loverlock, H., Wood, R.J.K. and Wang, S.C. (2015) Wettability of hierarchically-textured ceramic coatings produced by suspension HVOF spraying. Journal of Materials Chemistry A, 1-12. (doi:10.1039/c5ta02130h).

Record type: Article

Abstract

A novel but simple path for the preparation of superhydrophobic and superhydrophilic coatings has been demonstrated via a recently developed technology, namely Suspension High Velocity Oxy-Fuel spraying. Potential uses for robust superhydrophobic coatings include antifouling applications such as aeroplane wings, ship hulls, offshore wind turbine blades, or the above-deck structures on ice breaker vessels. Several fabrication techniques have been reported for preparing inorganic superhydrophobic surfaces, but existing coatings either lack the necessary robustness for engineering applications and/or their deposition methods are not suitable for industrial scale-up. In this work, the industrially established HVOF coating process was adapted to use a liquid suspension of commercially available nano-particles (Titania — TiO2, and hexagonal boron nitride — h-BN) as feedstock to produce nanostructured suspension HVOF TiO2/h-BN coatings for the first time on stainless steel. Results indicate that agglomerates in the nano-feedstock can be dispersed by h-BN due to poor mutual wettability between h-BN and molten TiO2. It also inhibits the anatase-to-rutile transformation of TiO2 during coating deposition by inhibiting sintering of TiO2 in the HVOF flame. The resultant coating becomes superhydrophobic when the addition of h-BN reaches 10 wt.% due to the presence of hierarchical nano-texture on the surface. The superhydrophobicity (contact angle of 163-170º) is maintained over a long period of time (>13 months, test still ongoing) and remains stable after exposure to light and tape test. A potential route for industrial preparation of robust water-repellent coatings is therefore highlighted by the study.

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C5TA02130H.pdf - Accepted Manuscript
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Accepted/In Press date: 1 June 2015
e-pub ahead of print date: 1 June 2015
Organisations: Inst. Sound & Vibration Research, nCATS Group

Identifiers

Local EPrints ID: 377808
URI: http://eprints.soton.ac.uk/id/eprint/377808
ISSN: 2050-7488
PURE UUID: e226f360-3834-47c7-9b54-b6cdcb0f5fd8
ORCID for R.J.K. Wood: ORCID iD orcid.org/0000-0003-0681-9239

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Date deposited: 08 Jun 2015 14:07
Last modified: 15 Mar 2024 02:47

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Contributors

Author: F. Zhang
Author: B. Robinson
Author: H. Villiers-Loverlock
Author: R.J.K. Wood ORCID iD
Author: S.C. Wang

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