Investigation of electrophoretic deposition as a method for coating complex shaped steel parts in solid oxide cell stacks

Electrophoretic deposition (EPD) is a promising method for coating complex shaped interconnects and contact components for solid oxide fuel cells and electrolyzers. In this work, we employ a combination of finite element modelling and experiments to assess the effect of substrate curvature on the fa...

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Bibliographic Details
Published in:Surface & coatings technology 2019-12, Vol.380, p.125093, Article 125093
Main Authors: Talic, B., Wulff, A.C., Molin, S., Andersen, K.B., Zielke, P., Frandsen, H.L.
Format: Article
Language:English
Subjects:
Coating
Cracks
Curvature
Electrolytic cells
Electrophoretic deposition
Ferritic stainless steels
Finite element method
Finite element model
Interconnect
Oxidation
Oxidation rate
Protective coatings
Sintering
Solid oxide fuel cell
Solid oxide fuel cells
Substrates
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Summary:Electrophoretic deposition (EPD) is a promising method for coating complex shaped interconnects and contact components for solid oxide fuel cells and electrolyzers. In this work, we employ a combination of finite element modelling and experiments to assess the effect of substrate curvature on the fabrication of a Mn1.5Co1.5O4 coating by EPD. The coating is deposited on steel substrates machined to create a well-defined curvature and on a Crofer 22 H steel grid. We find that post-deposition sintering of the coated steel substrate may lead to crack formation in concave surfaces, while a defect-free coating is achieved at convex surfaces. The formation of cracks is found to depend on a complex interplay between the coating thickness, the sintering procedure, and the substrate curvature radius. Oxidation testing in air at 750 °C showed that the Mn1.5Co1.5O4 coating reduced the oxidation rate of the Crofer 22 H steel grid. Sintering the coating by a two-step reduction and re-oxidation procedure resulted in a more protective coating showing a greater tendency for crack healing compared to sintering the coating in air only. [Display omitted] •Electrophoretic deposition evaluated for coating SOFC interconnects and steel grids.•Post-deposition sintering led to crack formation in concave surfaces.•Finite element model used to determine critical curvature radius to avoid cracking.•Mn1.5Co1.5O4 coating reduced the oxidation rate of a Crofer 22 H steel grid.
ISSN:0257-8972
1879-3347
DOI:10.1016/j.surfcoat.2019.125093