Chemical and Thermal Expansion of Calcium-Doped Lanthanum Chromite

Atomistic free-energy minimization techniques were used to simulate three simultaneous volumetric shrinkage/expansion phenomena in calcium-doped lanthanum chromite solid oxide fuel cell (SOFC) interconnect materials. Four sets of interatomic potentials were developed and tested over the temperature range 0–1273 K. The predicted unit-cell volumes, elastic properties, volumetric shrinkage due to A-site doping of the ABO3 perovskite (La1-xCax)CrO3, defect-induced volumetric expansion due to reducing atmospheres, and thermal expansion were in reasonable agreement with experiment, though not all concurrently with a single set of potentials. Potentials based either on simple oxides or on partial charge models appeared to give the best overall predictions. Additional experimental data are needed to improve the potentials.