Authors: |
Jouni Puranen* / Tampere University of Technology, Department of Materials Science, Finland Leo Hyvärinen / Tampere University of Technology, Department of Materials Science, Finland Juha Lagerbom/ VTT, Technical Research Centre of Finland, Finland Mikko Kylmälahti/ Tampere University of Technology, Department of Materials Science, Finland Heli Koivuluoto/ Tampere University of Technology, Department of Materials Science, Finland Petri Vuoristo/ Tampere University of Technology, Department of Materials Science, Finland
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Abstract: |
Mn-Co spinels are used as protective coatings on metallic interconnectors (ICs) in solid oxide fuel cells (SOFCs) to prevent the formation of a chromium oxide scale and evaporation of harmful chromium compounds which cause degradation of the cell. Conventional plasma spraying is used on manufacturing cell components. In addition to this, nowadays new thermal spraying technique, e.g., suspension spraying is widely studied as potential manufacturing methods as well.
Suspension plasma spraying (SPS) is regarded as a promising way to produce new coating structures with improved properties. In this study, SPS was studied as a possible manufacturing process for thin Mn-Co spinel coatings used as protective coatings. Suspension of nanosized MnCo2O4 powder and ethanol was sprayed by using F4-MB plasma gun with radial external suspension feeding. The influence of spraying parameters, such as plasma gas composition and total gas flow, current and spraying distance for coating architecture were studied using field-emission scanning electron microscope (FESEM) and x-ray diffraction (XRD). Spraying parameters had a strong influence on coating architecture and composition. Coating with the most homogenous structure formed when sprayed with low energy spraying parameter whereas high energy parameter formed a columnar structure with larger cobalt rich areas.
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