Investigation of Chromium Vaporization from Interconnector Steels with Spinel Coatings

Abstract

The vaporization of Cr-rich volatile species from interconnector materials for high temperature solid oxide fuel cells (SOFCs) is considered to be a major source of degradation that limits the lifetime of planar SOFC systems [ Fujita , J. Power Sources , 131 , 262 (2004) ; 160 , 1104 (2006) ; Hilpert , J. Electrochem. Soc. , 143 , 3642 (1996) ; Kurukowa , Solid State Ionics , 178 , 287 (2007) ; Quadakkers , SOFC Forum , p. 323 (1994) ; Quadakkers , European Oxide Fuel Cell Forum , p. 297 (1996) ]. For a longer lifetime of these systems, the Cr vaporization of interconnector material is reduced [ Collins , Surf. Coat. Technol. , 201 , 4467 (2006) ]. The potential of reduction of Cr vaporization using coatings with spinel layers is the subject of the present work. In this study, the influence of processing parameters for Crofer22APU coated with a spinel based on on the Cr vaporization rates was studied at in air using the transpiration method. The measured Cr release of the coated samples was compared to an uncoated Crofer22APU. The aim of this work was to find the optimum conditions to prepare the spinel coating with regard to Cr vaporization.