Performance Evaluation of Candidate Materials For Solid Oxide Cell Interconnects

Abstract

This thesis examines the oxidation kinetics and the chromium evaporation of possible SOFC interconnect materials at 800 °C in air with 3% water vapor. The selected materials are AISI 441, AISI 446, Nirosta (Industrial Melt 1), and Crofer 22 APU. The study shows that the oxidation kinetics of these steels are varied, with AISI 441 and Crofer 22 APU showing dissimilar behaviors compared to AISI 446 and Nirosta (IM 1). Among the materials, Crofer 22 APU exhibits a mass loss, indicating unique oxidation kinetics. Chromium evaporation rates also differ, with AISI 441 showing the highest average evaporation rate and Crofer 22 APU the lowest, suggesting better protective properties of the oxide scale formed on the surface of Crofer 22 APU. The findings highlight that Crofer 22 APU, due to its protective oxide scale, is the most promising candidate for SOFC interconnects under the tested conditions. Furthermore, the possibility of using Nirosta (IM 1) or AISI 446 materials as cheaper counterparts although, they exhibit somewhat higher values of the chromium emission rate over time in comparison with Crofer 22 APU.