Influence of powder composition and manufacturing method on electrical and chromium barrier properties of atmospheric plasma sprayed spinel coatings prepared from MnCo 2 O 4 and Mn 2 CoO 4 þ Co powders on Crofer 22 APU interconnectors Jouni Puranen a,* , Mikko Pihlatie b , Juha Lagerbom c , Turkka Salminen d , Jarmo Laakso a , Leo Hyv € arinen a , Mikko Kylm € alahti a , Olli Himanen b , Jari Kiviaho b , Petri Vuoristo a a Tampere University of Technology, Department of Materials Science, P.O. Box 589, FI-33101, Tampere, Finland b VTT, Technical Research Centre of Finland, P.O. Box 1000, FI-02044, VTT, Finland c VTT, Technical Research Centre of Finland, P.O. Box 1300, FI-33101, Tampere, Finland d Tampere University of Technology, Optoelectronics Research Centre, P.O. Box 692, FI-33101, Tampere, Finland article info Article history: Received 31 March 2014 Received in revised form 1 August 2014 Accepted 10 August 2014 Available online 11 September 2014 Keywords: Solid oxide fuel cell Metallic interconnect Plasma spraying Spinel coating ASR abstract Protective coatings based on manganese cobalt oxide spinels are required in solid oxide fuel cells (SOFCs) to prevent the evaporation of volatile Cr(VI)-compounds from the metallic interconnectors and to minimize high temperature corrosion. Atmospheric plasma spraying (APS) was used to manufacture dense manganese cobalt oxide protective coatings on Crofer 22 APU substrates by employing two different spinel powders. The spray powders were MnCo 2 O 4 and Mn 2 CoO 4 þ Co (equivalence for Mn 1.5 Co 1.5 O 4 ). The Mn 2 CoO 4 þ Co powder was prepared by agglomerating the oxide powder with fine metallic cobalt powder. The coated substrates were oxidized at 700  C in air for 1000 h. During the high temperature oxidation, a four-point on-line measurement technique with a current density of 640 mA/cm 2 was simultaneously used for area specific resistance (ASR) studies. The coatings were characterized by X-ray diffraction (XRD), field-emission scanning elec- tron microscopy (FESEM), an energy dispersive spectrometer (EDS) and Raman spectroscopy. The APS coatings had dense microstructure, which decreased the oxidation of the substrate. The MnCo 2 O 4 coating showed indication of some Cr-migration, whereas Mn 2 CoO 4 þ Co showed good Cr-barrier properties. The ASR test showed that APS coated Mn 2 CoO 4 þ Co is a promising candidate material for SOFC interconnect applications. Copyright © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. * Corresponding author. Tel.: þ358 40 849 0195. E-mail address: jouni.puranen@tut.fi (J. Puranen). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 39 (2014) 17246 e17257 http://dx.doi.org/10.1016/j.ijhydene.2014.08.016 0360-3199/Copyright © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.