Effects of Mn concentration on durability of Fe-Cr ferritic steels dispersed with La2O3 for solid oxide fuel cell interconnects

Abstract

This study investigates the effect of Mn concentration in La2O3-dispersed ferritic steel on the oxidation behavior, area-specific resistance (ASR), and chromium volatilization for solid oxide fuel cell (SOFC) interconnects. The results show that increasing Mn concentrations lead to a gradual increase in the oxidation rate of the alloy samples. The alloy with 0.3 wt% Mn primarily forms Cr2O3 during the initial oxidation stage, whereas the alloys containing more than 1.0 wt% Mn promote the growth of (Mn,Cr)3O4, leading to an accelerated oxidation rate. The ASR value exhibits a decreasing trend initially, followed by an increasing trend, as the Mn concentration in the alloy increases from 0.3 to 2.0 wt%. The alloy with 1.0 wt% Mn shows the lowest ASR value of 12.2 mΩ cm2 after 1000 h. The alloys demonstrate a tendency to reduce chromium volatilization as the Mn concentration increases, which can be attributed to the growth of (Mn,Cr)3O4 at the topmost layer of the oxide. The study suggests that controlling the Mn concentration in the Fe-Cr alloys can help in reducing the ASR values and Cr volatilization, making the ferritic steel alloy with 1.0 wt% Mn an effective choice for SOFC interconnects.