Kinetic demixing/decomposition of Ba0.5Sr0.5CoxFe1−xO3−δ (x = 0.2 and 0.8)

Abstract Microstructural changes due to kinetic demixing within sintered BSCF ceramics (Ba 0.5 Sr 0.5 Co x Fe 1− x O 3− δ , x  = 0.2 and 0.8: BSCF5528 and BSCF5582, respectively) have been investigated. When the specimens were subjected to 2 A/cm 2 at 1000 °C and p O 2  = 10 −5  atm, there was a significant enhancement of grain growth as well as 2nd phase formation observed in BSCF5528. At the anode, cobalt deficient aggregates within the grains; and, at the cathode, cobalt rich 2nd phase particles were observed on the grain surfaces of the microstructure. Such phenomena were not observed in BSCF5582, even under higher current density (7 A/cm 2 ) and longer delay time. These results were explained by the kinetic demixing/decomposition.