Correlation between defect chemistry and expansion during reduction of doped LaCrO3 interconnects for SOFCs

Reduction of doped lanthanum chromite results in a linear expansion of the sample depending on dopant concentration, temperature, and oxygen content w ithin the sample. In order to elucidate the defect structure of the perovsk ite-type oxide solid solution La1-xCaxCrO3-delta (x = 0.10 and 0.20), the n onstoichiometry delta was measured as a function of oxygen partial pressure from 900 to 1100 degrees C by means of a thermogravimetric method. The the rmal expansion in reducing environments was measured as a function of oxyge n partial pressure at 1000 degrees C and then related to the change in oxyg en stoichiometry. A linear correlation between thermal expansion and oxygen nonstoichiometry was found. (C) 2000 Published by Elsevier Science B.V. Al l rights reserved.