Dimensional Instability of Doped Lanthanum Chromites in an Oxygen Pressure Gradient

The volume expansion of samples of Lai-^Caj/CrOa-^ in reducing at­ mosphere was measured for various degrees of doping. Combining the experimental data with calculated profiles of oxygen partial pressure, pO2, through plates exposed to pO2 differences relevant for SOFC in­ terconnectors, the overall expansion of the interconnector-plate, as well as the resulting stresses in the stack are estimated. The behaviour of Ca- and Sr-doped material is compared, and the optimal degree of doping, as judged from a mechanical point of view, is discussed.