Journal Article
ECS Transactions, vol. 1, iss. 7, pp. 325-332, 2006
Authors
Guanguang Gordon Xia, Zhenguo Gary Yang, Jeff Stevenson
Abstract
The adoption of ferritic stainless steels for SOFC interconnects is still under intensive evaluation due to the unresolved issues of chromium poisoning, low electrical conductivity, and long-term instability of the oxide scales. Application of manganese-cobalt spinel protection layers on the steel interconnects may be an effective approach to solve the problems. For an optimized performance, a series of MnxCo3-xO4 (0<x<3) spinels were investigated. It was found that the spinel with x around 1.5 demonstrates a good CTE match to the adjacent cell components, high electrical conductivity (61.6 S/cm at 800oC), and a good thermal stability up to 1250oC. The material suitability was confirmed by a long-term test on the Mn1.5Co1.5O4 protection coating layer that was thermally grown on Crofer22 APU, indicating the spinel protection layer not only significantly decreased the contact resistance between the LSF cathode and the stainless steel interconnect, but also inhibited the sub-scale growth on the stainless steel.
