Effects of Surface-Deposited Nanocrystalline Chromite Thin Films on the Performance of a Ferritic Interconnect Alloy

Abstract

LaCrO3 -based nanocrystalline thin films, substituted with Sr and Zn and coated onto a Fe-26 atom % Cr Ebrite alloy were evaluated at 750-900°C as potential enhancers of oxide properties in ferritic alloy interconnects of a solid oxide fuel cell. It was found that at 750°C the coatings provided (i) lower oxidation rates, (ii) increased electrical conductivity, (iii) protection during 24 h cycling and at least 2375 h of isothermal oxidation, and (iv) a fine-grained and uniform oxide microstructure. Although after oxidation at 850°C the grains grew substantially and the scale seemed to be overgrowing the film, conductivity and oxidation rates still matched that of the uncoated sample. Tensile tests showed that the coating improved scale adhesion after a 100 h oxidation at 850°C. At 900°C, the film was still capable of blocking 70% of the Cr that evaporated from an uncoated Ebrite substrate. © 2007 The Electrochemical Society.