Development of (Mn,Co)3O4 Protection Layers for Ferritic Stainless Steel Interconnects [report]

Zhenguo Yang, Steven P. Simner, Prabhakar Singh, Guanguang Xia, Jeffry W. Stevenson
2005 unpublished
ph: (865) 576-8401 fax: (865) 576-5728 email: reports@adonis.osti.gov Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161 ph: (800) 553-6847 fax: (703) 605-6900 email: orders@ntis.fedworld.gov online ordering: http://www.ntis.gov/ordering.htm This document was printed on recycled paper. A spinel-based surface protection layer has been developed for alloy SOFC current collectors and bi-polar gas
more » ... s. The (Mn,Co) 3 O 4 spinel with a nominal composition of Mn 1.5 Co 1.5 O 4 demonstrates an excellent electrical conductivity and thermal expansion match to ferritic stainless steel interconnects. A slurry-coating technique provides a viable approach for fabricating protective layers of the spinel onto the steel interconnects. Thermally grown protection layers of Mn 1.5 Co 1.5 O 4 have been found not only to significantly decrease the contact resistance between a LSF cathode and stainless steel interconnect, but also inhibit the sub-scale growth on the stainless steel. The combination of the inhibited sub-scale growth, good thermal expansion matching between the spinel and the stainless steel, and the closed-pore structure contribute to the excellent structural and thermomechanical stability of these spinel protection layers, which was verified by a long-term thermal-cycling test. The spinel protection layers can also act effectively to prevent outward diffusion of chromium from the interconnect alloy, preventing subsequent chromium migration into the cathode and contact materials. PNNL is currently engaged in studies intended to optimize the composition, microstructure, and fabrication procedure for the spinel protection layers.
doi:10.2172/1042570 fatcat:wrwq3ci4vfaclkplep3lnwonem