Metallic materials in solid oxide fuel cells

Abstract

Fe-Cr alloys with variations in chromium content and additions of different elements were studied for potential application in intermediate temperature Solid Oxide Fuel Cell (SOFC). Recently, a new type of FeCrMn(Ti/La) based ferritic steels has been developed to be used as construction material for SOFC interconnects. In the present paper, the long term oxidation resistance of this class of steels in both air and simulated anode gas will be discussed and compared with the behaviour of a number of commercial available ferritic steels. Besides, in-situ studies were carried out to characterize the high temperature conductivity of the oxide scales formed under these conditions. Main emphasis will be put on the growth and adherence of the oxide scales formed during exposure, their contact resistance at service temperature as well as their interaction with various perovskite type contact materials. Additionally, parameters and protection methods in respect to the volatilization of chromia based oxide scales will be illustrated.

Growth Mechanisms and Electrical Conductivity of Oxide Scales on Ferritic Steels Proposed as Interconnect Materials for SOFC's

“…Both materials were of the type FeCrMn(Ti/La) [5][6][7]. The first material, designated as steel (A), was made of high purity elements, whereas the other steel (B) contained approximately 0.1 wt.-% each of Si and Al [17].…”

“…This paper presents experimental data concerning the electrical conductivity of surface oxide scales formed in the temperature range from 600-800 C on two selected high-chromium, ferritic steels, which were recently developed specifically for SOFC applications [5][6][7]. The data are correlated with oxide scale morphologies and scale formation mechanisms and the results are compared with those obtained for two "pure chromia" forming materials.…”

Kinetics of High Temperature Oxidation and Chromia Volatilization for a Binary Ni–Cr Alloy

“…This phenomenon can become problematical at very high temperatures, in aeronautics 4,5 as well as in other fields where chromia-forming alloys are used, such as solid oxide fuel cells (SOFCs), as demonstrated in recent works. 6,7 The rate of chromia volatilization is negligible below 1000 • C but increases with temperature and must be taken into account for very high temperatures. If not, determination of the parabolic constants by thermogravimetry becomes more difficult and leads to values that are too low to represent correctly the real damage caused by oxidation of the alloy.…”

Structural and magnetic properties of bulk alloys and aerosol nanoparticles in the Fe100−xCrx system

“…Besides displaying good mechanical, anticorrosive [1] and wear resistance [2] properties, Fe-Cr alloys are also of technological interest as catalysts of the water gas shift reaction that eliminates the CO produced during the fuel cells operation [3]. They have also been proposed as a cheaper substitute of LaCrO 3 , as the interconnect material in solid oxide fuel cells [4,5], and as thin films, are tested for enhancing the magnetoresistance and the thermal stability of synthetic spin valves [6].…”