Manganese–Cobalt Based Spinel Coatings Processed by Electrophoretic Deposition Method: The Influence of Sintering on Degradation Issues of Solid Oxide Cell Oxygen Electrodes at 750 °C

Abstract

This paper seeks to examine how the Mn–Co spinel interconnect coating microstructure can influence Cr contamination in an oxygen electrode of intermediate temperature solid oxide cells, at an operating temperature of 750 °C. A Mn–Co spinel coating is processed on Crofer 22 APU substrates by electrophoretic deposition, and subsequently sintered, following both the one-step and two-step sintering, in order to obtain significantly different densification levels. The electrochemical characterization is performed on anode-supported cells with an LSCF cathode. The cells were aged prior to the electrochemical characterization in contact with the spinel-coated Crofer 22 APU at 750 °C for 250 h. Current–voltage and impedance spectra of the cells were measured after the exposure with the interconnect. Post-mortem analysis of the interconnect and the cell was carried out, in order to assess the Cr retention capability of coatings with different microstructures.

Parameters Optimization for Electrophoretic Deposition of Mn1.5Co1.5O4 on Ferritic Stainless Steel Based on Multi-Physical Simulation

“…Sun et al 10,11 deposited Cu-Mn spinel on Crofer 22 APU substrate by EPD, and further diffusion of Cr was prevented effectively. Zanch et al, 12 Zhang et al, 13 and Abdoli et al 14 successfully deposited Mn-Co spinel on Crofer 22 APU and SUS430 substrates, respectively.…”

Review—(Mn,Co)3O4-Based Spinels for SOFC Interconnect Coating Application

“…have been produced by various deposition techniques, such as slurry coating (e.g., brush painting, wet powder spray, dip coating, and screen printing), 33,35,[106][107][108][109] thermal spray, [110][111][112][113][114][115][116][117] physical vapor deposition (PVD) (e.g., electron beam PVD, EBPVD, thermal evaporation, sputtering, etc. ), [118][119][120][121][122] electrodeposition, [123][124][125][126][127] electrophoretic deposition (EPD), 95,97,126,[128][129][130][131][132][133] etc. The choice of deposition techniques mainly depends on the coating composition/ thickness, surface topography of the interconnect, and cost of equipment.…”

“…A relatively dense and crack-free MCO spinel coating was formed on the substrate surface through EPD of the precursor layer followed by the reduction/reoxidation steps with a re-oxidation/sintering temperature of 900--1000 °C. 95,97,126,[129][130][131][132][133]160 Talic et al compared the coating quality of an EPD-processed MnCo 1.7 Fe 0.3 O 4 coating after different sintering processes. 161 As schematically shown in Fig.…”