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

Abstract

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.

Mn-Co spinel coatings on Crofer 22 APU by electrophoretic deposition: Up scaling, performance in SOFC stack at 850 °C and compositional modifications

“…In addition, these techniques may not lead to uniform deposition in case of IC complex shapes (i.e. channelled surfaces) in comparison with wet methods such as electroplating or electrophoretic deposition [17][18][19].…”

“…On the other hand, Talic et al [19] successfully assessed electrophoretic deposition (EPD) as suitable technique to obtain a uniform thickness of the protective layer even on complex shapes. In addition, their work pointed out that the post-deposition treatments (i.e.…”

Preparation, Properties and Mechanisms of Carbon Fiber/Polymer Composites for Thermal Management Applications

“…The smooth surface is more beneficial to enhance the uniform distribution of the reinforced material on the surface and to enhance the thermal conductivity of the CF composite material. Talic et al [ 72 ] deposited the M n1.5 Co 1.5 O 4 material on the steel substrate by EPD method. Due to the different thickness of the concave surface, the sintered coated steel substrate was prone to crack.…”

Recent advances in electrophoretic deposition of thin-film electrolytes for intermediate-temperature solid oxide fuel cells

“…For the manufacture of tubular SOFCs, the EPD installations are organized with a cylindrical counter electrode and deposition is carried out on a coaxially mounted central electrode. Planar installations were successfully used for the deposition of dense electrolyte layers, including multilayer or composite structures deposited on porous cathodes, anodes or dense electrolyte substrates [54,76,114,115], barrier and protective layers [83,116,117], porous electrodes [118-120]. Cylindrical EPD installations were adopted for the formation of functional layers, half cells or full structures of microtubular SOFCs [58,86,121].…”