TY  - JOUR
AU  - Ran, Ke
AU  - Deibert, Wendelin
AU  - Du, Hongchu
AU  - Park, Daesung
AU  - Ivanova, Mariya E.
AU  - Meulenberg, Wilhelm A.
AU  - Mayer, Joachim
TI  - Processing-induced secondary phase formation in Mo-substituted lanthanum tungstate membranes
JO  - Acta materialia
VL  - 180
SN  - 1359-6454
CY  - Amsterdam [u.a.]
PB  - Elsevier
M1  - FZJ-2019-04638
SP  - 35 - 41
PY  - 2019
AB  - The compositional homogeneity of a technically relevant hydrogen separation membrane, La5.4W0.8Mo0.2O12-δ (LWO-Mo20), was studied using comprehensive transmission electron microscopy (TEM) techniques. The membrane is predominantly composed of dense LWO-Mo20 grains with a defect fluorite structure. In addition to the primary phase, the observed secondary phase (SP) grains were identified as La2/3(Mg1/2W1/2)O3, with the W sites partially occupied by Mo, Fe and Al. Part of the SP grains were incorporated into single LWO-Mo20 grains through smart orientations, in which massive structural defects at the interface of the LWO-Mo20 and SP grains are efficiently avoided. Slight elemental disorder is limited within a few atomic layers. In contrast, the LWO-Mo20 grains share barely common features with neighboring SP grains, and are unstable under electron beam irradiation. The formation of the SP was tracked back to the traces of impurities in the precursors. Excluding such impurities is technically challenging and unacceptable in terms of cost. Hence, our results here show an opportunity to remedy these impurities through engineering the SP into individual primary grains, in which even a significant cost reduction could thus be realized.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000495519100005
DO  - DOI:10.1016/j.actamat.2019.08.053
UR  - https://juser.fz-juelich.de/record/865076
ER  -