Lattice Expansion of Acceptor-doped Lanthanum Chromites under High-temperature Reducing Atmospheres

Abstract

The dimensional changes of doped lanthanum chromites (LaCrO3) upon reduction were investigated by thermal expansion measurements in oxidizing and reducing atmospheres. Judging from the crack formation in these experiments, an empirical guideline for materials selection of LaCrO3-based interconnectors in solid oxide fuel cells has been identified that materials showing relative linear expansions of less than 0.1% are to be used. It was also found that the lattice expansion increased with decrease of oxygen partial pressure (P(O2)) and showed a trend to saturate at very low P(O2). This trend has successfully been elucidated by a simple model derived by using Vegard's law.