Plasma spraying of lanthanum chromite films for solid oxide fuel cell interconnection application

This paper discusses a novel plasma-spraying process for depositing dense LaCrO3-based interconnection for solid oxide fuel cells (SOFCs), Calcium aluminate was mixed with LaCrO, in a slurry containing PVA binder and spray dried to form free-flowing agglomerates. These free-flowing agglomerates mere plasma sprayed onto a porous substrate of doped LaMnO3 and then heat-treated to form a gas-tight and electrically conducting interconnection. Samples of the plasma-sprayed interconnection were characterized for morphology, phase constituents, and coefficient of thermal expansion, as well as electrical resistivity and oxygen nonstoichiometry at 1000 degrees C in the P-O2 range from 1 to similar to 1 x 10(-16) atm. The calcium aluminate additive was found to facilitate densification of the interconnection, most likely through the formation of low-temperature melting phase(s) in the system Ca-Cr-Al-O, A SOFC with such a plasma-sprayed interconnection was fabricated and electrically tested. This cell exhibited good electrical performance, and the interconnection was stable under fuel cell operation conditions.