Perovskite-type membranes of (Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ (BSCF) and

(Ba0.5Sr0.5)(Fe0.8Zn0.2)O3−δ (BSFZ) were successfully prepared via liquid-phase

sintering using BN as sintering aid. The obtained membranes were examined via

powder X-ray diffraction pattern, differential scanning calorimetry, scanning

electron microscopy, transmission electron microscopy and oxygen permeation

experiments. It has emerged that the use of BN as sintering aid lowers sintering

temperatures in order to obtain dense membranes with relative densities in the

range of 93–96% as proven by the Archimedes method. It was further shown that

the perovskite structure could be maintained after sintering with BN. Additionally,

BN was completely removed from the sintered membranes. Investigation of the

microstructure revealed that the average grain size of the membranes was

influenced by the amount of BN added prior the sintering process. It was found that

large amounts of BN effectively lower the average grain size. Oxygen permeation

experiments have shown that the lower the average grain size the lower the oxygen

permeation performance, particularly in the case of BSCF. Transmission electron

microscopy revealed that no evidence for an amorphous layer or any other

interfacial phase in the grain boundary was present.

Grain Boundaries as Barrier for Oxygen Transport in Perovskite-Type

Membranes. M.Arnold, J.Martynczuk, K.Efimov, H.Wang, A.Feldhoff: Journal of

Membrane Science, 2008, 316[1-2], 137-44