TG Measurements of the Oxidation Kinetics of Fe—Cr Alloy with Regard to its Application as a Separator in SOFC

Author: Brylewski T.   Maruyama T.   Nanko M.   Przybylski K.  

Publisher: Springer Publishing Company

ISSN: 1388-6150

Source: Journal of Thermal Analysis and Calorimetry, Vol.55, Iss.2, 1999-02, pp. : 681-690

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Abstract

The high-temperature oxidation behavior of a ferritic alloy (SUS 430) in a SOFC environment, corresponding to the anode (H2/H2O gas mixture) and cathode (air) operating conditions, was determined with regard to application of the alloy as a metallic separator material in SOFC. The oxidation kinetics of Fe—16Cr alloy (SUS 430), was studied by thermogravimetry in H2/H2O gas mixtures with and 97/3 and in air, in the temperature range 1023–1223 K, for 3.6 up to 1080 ks. It was found that the protective oxide scale, composed mainly of Cr2O3 with uniform thickness and excellent adhesion to the metal substrate, grows in accordance with the parabolic rate law. The dependence of the parabolic rate constant, k p, of the scale on temperature obeys the Arrhenius equation: k p=6.8×10−4 exp (−202.3 kJ mol−1R−1T−1) for H2/H2O gas mixtures with . The determined k p was independent of the oxygen partial pressure in the range from 5.2×10−22 to 0.21 atm at 1073 K, which means that the rates of growth of the scale on Fe—16Cr alloy in the above-mentioned atmospheres are comparable. The oxidation test results on Fe—16Cr alloy in H2/H2O gas mixtures and air demonstrate the applicability of SUS 430 alloys as a separator for SOFC.