중온용 SOFC 인터커넥트재에 적용하기 위한 12Cr 및 15Cr 내열강 소재의 특성 연구

Abstract

This study has been conducted to investigate the properties of 12%Cr and 15%Cr heat resistance steels for solid oxide fuel cell (SOFC) interconnects. The results obtained from this study are summarized as follows; Microstructure of two specimens showed the two phase mixture structure by presence of ferrite phase in the martensite phase. With an increasing of oxidation time and temperature, the weight gain of two specimens increased. Degree of oxidation in heat resistance steel with the 12% Cr was higher than 15% Cr. The Cr2O3 and (Mn,Cr,Fe)3O4 oxides were generated in oxide layer of two specimens, and high concentration of Fe, Cr and Mn oxides was locally produced in oxide layer. In the oxide layer, the concentration of Cr, Mn and O was increased, while the concentration of Fe was decrased less than matrix concentration. A thermal expansion coefficient of the heat resistance steel with 12% Cr was higher than 15% Cr, but the difference between them was small. Thermal expansion coefficient of both samples satisfied the requirements for interconnect materials of solid oxide fuel cell.