Novel low Cr-containing alloys for intermediate temperature solid oxide electrochemical devices

Abstract

The most popular alloys for solid oxide fuel cells (SOFC) and solid oxide electrolysis cells (SOEC) interconnects are ferritic stainless steels such as Crofer 22 APU with high chromium contents of more than 22 wt%. The main problem with these steels is that in oxidising atmospheres under SOFC operating conditions, chromium evaporates from them, causing electrode degradation. The possibility of solving this problem by creating precision alloys with low chromium content and a certain level of electrophysical and mechanothermal properties is discussed. This work presents novel alloys based on Ni-Mo and Co-Fe systems with a chromium content of no more than 6 wt%. It has been shown that the alloys meet the requirements of oxidation resistance and mechanothermal compatibility with electrolytes based on cerium dioxide and lanthanum gallate for intermediate temperature solid oxide electrochemical devices. Properties of these alloys such as linear thermal expansion, oxidation resistance and specific resistance meet the requirements for materials of intermediate temperature solid oxide electrochemical devices in the operating temperature range. This fact allows us to consider the alloys as promising materials for use as interconnects of SOFCs and SOECs, but further research is required.