DIMENSIONAL STABILITY AND DEFECT CHEMISTRY OF DOPED LANTHANUM CHROMITES

Acceptor doped lanthanum chromites are potential interconnect material s to be used in high temperature Solid Oxide Fuel Cells (SOFC). Howeve r, instability of these materials when exposed to low oxygen partial p ressure causes a volume expansion that can be detrimental to the SOFC performance. The stability of L0.8Sr0.2Cr0.97V0.03O3 determined as fun ction of pO(2) and temperature by isothermal thermogravimetry and dila tometry. The experimental data are analysed using a simple model fbr t he defect chemistry. The relation between expansion behaviour and chan ge in defect chemistry is discussed using a simple structural model.