Phase-boundary grooving at surfaces of solid oxide fuel cell materials

Thermal grooving was studied on the interfaces between two ceramic phases. Specimens of two-phase materials, lanthanum strontium manganite (LSM) and cerium oxide, 50-50 vol%, were prepared by mechanical milling and sintered at 1400 °C for 24 hrs. LSM and ceria are two important components for new generation solid oxide fuel cells (SOFC), and the boundary between these two and gas phase, forming a triple phase boundary (TPB), plays a significant role in the performance of a fuel cell. For the thermal grooving study, LSM-ceria specimens were polished and heat treated at 1400 °C for three annealing times. The phase boundaries were characterized and monitored by FESEM and AFM. It has been noticed that the formation and evolution of grooving at two-phase interfaces are similar to those observed in grain boundaries of single-phase systems. The preliminary data of the groove dimensions are presented.