Effect of Manganese Concentration in Cerium Oxide Dispersed Ferritic Stainless Steels on Oxidation Behavior for Metallic Interconnect Material of Solid Oxide Fuel Cell

Abstract

The ferritic stainless steel is used as interconnect materials of planar solid oxide fuel cell (SOFC) stack designs. However, the formation of a Cr2O3 oxide layer on the metallic interconnect is inevitable in the SOFC cathodic environment, and the formed layer decreases its electrical conductivity. In this study, we have investigated the effect of manganese (Mn) concentration in the cerium oxide (CeO2) dispersed ferritic stainless steels on oxidation behavior of SOFC metallic interconnect. The mixed powders with various Mn concentrations of 0.5 to 2wt.% were prepared by high-energy ball milling (HEBM), and subsequently were pelletized and sintered at 1400oC in reduction atmosphere. The area specific resistance (ASR) tests were carried out for 1,000 hrs. in air at 800 oC. The material characterization and morphology analysis of the tested samples were performed. After oxidation test, the oxide scale formed on the surface of the sample with Mn was confirmed as a Mn-Cr spinel structure. The thickness of the oxide scales increased with Mn concentration of the samples. Among the various Mn compositions, the sample with 1wt.% Mn had the lowest area specific resistance. The results show that the Mn in the ferritic stainless steel has great influence on the oxidation behavior. In this talk, we will discuss these results as related the requirements of the SOFC metallic interconnect.