Electrophoretic Deposition of Advanced Ceramic Coatings for High Temperature Corrosion Protection of Steel Interconnects for Solid Oxide Cells

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Microstructural, thermo-mechanical and corrosion properties of electrophoretically co-deposited Cu and Fe doped Mn–Co spinel coatings for solid oxide cell interconnects

Chromia forming ferritic stainless steels are employed as interconnects in SOC stacks; the deposition of a manganese cobalt spinel protective coating is widely accepted as a viable solution to mitigate both the oxidation and the chromium evaporation. Electrophoretic deposition (EPD) offers the possibility to deposit homogeneous coatings in few seconds and at room conditions and the need of a simple and adaptable apparatus, thus reducing processing time and cost. A successful deposition is ensured by the optimization of both the starting suspensions in terms of colloidal properties and the post-deposition sintering profile. Electrophoretic co-deposition is an innovative approach for the simultaneous deposition of spinel precursors and for designing in-situ modified manganese-cobalt spinel coatings. A systematic microstructural, thermo-mechanical and electrical characterization of simultaneous Fe–Cu doped Mn–Co spinel coatings processed by electrophoretic co-deposition on Crofer22APU is here reported and discussed. We demonstrate the feasibility to co-deposit Fe2O3, CuO and Mn–Co spinel to produce dense, stable and effective doped spinel coatings. Improved functional properties of produced coatings are assessed in terms of microstructure development, oxidation kinetics and area specific resistance at SOC stack relevant conditions. Furthermore, an assessment of the dilatometric properties of the Fe–Cu doped spinels reveals the influence of different doping levels on the thermomechanical compatibility of the Fe–Cu doped Mn–Co spinel coatings with the interconnect. This work proposes the electrophoretic co-deposition method as an innovative approach for the simultaneous deposition of spinel precursors and for designing in-situ modified coatings

Electrophoretic Deposition of Ceramic Coatings for Solid Oxide Cells: Challenges and Perspectives

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Electrophoretic deposition of MnCo2O4 coating on solid oxide cell interconnects manufactured through powder metallurgy

Developing cost-effective and durable interconnects for solid oxide cells is crucial to overcome currently existing barriers for the commercialization of this promising energy technology. A systematic microstructural and electrical characterization of MnCo2O4 spinel coatings processed by electrophoretic deposition on SUS 445 ferritic stainless steel, manufactured through powder metallurgy, is here reviewed and discussed for application in high temperature solid oxide cells stacks. The work presents a successful com- bination of the powder metallurgy processing of metallic interconnects with the electrophoretic deposition as a fast and versatile approach to coat complex interconnect shapes. Therefore, this study assesses the effect of the sintering route of coated steel on the final microstructure. Remarkable results in terms of electrical properties are here presented for EPD coated sample reduced at 1000 °C and re-oxidised at 800 °C in static air, obtaining an area specific resistance degradation rate of 1.2 mΩ cm2/kh together with an effective limitation of Cr outward diffusion despite the prolonged exposure in relevant conditions. This novel approach opens the door for a new class of complex-shaped interconnects with enhanced performance and durability and excellent scalability at a low cost

Experimental review of the performances of protective coatings for interconnects in solid oxide fuel cells

Ferritic stainless steel interconnects are used in solid oxide fuel cells; however, coatings are required to improve their performance. Although several types of coatings have been proposed, they have been scarcely investigated under similar conditions. This study compares the characteristics of uncoated Crofer 22 APU and eight different coatings on Crofer 22 APU for up to 3000\ua0h at 800\ua0\ub0C. The coatings were deposited at various research laboratories around the world, and the experiments were performed at Chalmers University of Technology, Sweden. Cross-sections of the samples were analysed using scanning electron microscopy and energy-dispersive x-ray spectroscopy. The (Co,Mn)-based coated steels showed more than 50-fold lower chromium evaporation and at least 3 times thinner Cr2O3 scale thickness compared to uncoated steel. The coated steel samples showed lower area-specific resistance (ASR) values than the uncoated steel after 3000\ua0h of exposure, irrespective of the coating thickness, composition and deposition method

The electrophoretic deposition technique in Solid Oxide Cell technologies: from the protective coatings to new interface concepts

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Electrochemically enhanced wetting of 3YSZ and Mn1.5Co1.5O4 by Ag−CuO and their application in flash joining

Ag−CuO is a widely used air braze sealant for joining ceramic electrolytes and stainless-steel interconnects in solid oxide fuel cells (SOFCs). Balancing the amount of CuO in a braze is challenging because it enhances wettability and also aggravates steel surface degradation. Manganese cobaltite spinel (MCO) is widely used as a protective coating for SOFC steel interconnects. Therefore, we herein propose a strategy for enhancing the wetting of an Ag−CuO alloy with a low concentration of CuO (4 mol%) on 3 mol% yttria-stabilized zirconia (3YSZ) and MCO by applying a direct current to the 3YSZ/Ag−CuO/MCO system. It was discovered that the wetting of 3YSZ improved regardless of the current polarity; however, the wetting of MCO was selectively improved by the current flowing from MCO to 3YSZ. The underlying mechanisms are discussed based on the current-induced interfacial electrochemical reactions and dissolution. Furthermore, the flash joining of 3YSZ to MCO-coated Crofer22APU was achieved, and an optimized shear strength of 62 ± 11 MPa was obtained. A correlation between the interfacial microstructure, mechanical properties, current polarity and current intensity was also established

Recurrent neonatal late-onset group B streptococcal disease: Consider mother treatment

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