Klementina Zupan, Stane Pejovnik, Jadran Maček
Faculty of Chemistry and Chemical Technology, University of Ljubljana
Lanthanum chromite-based materials have a great potential for use in
various high temperature applications and as SOFC (solid oxide fuel cell)
separators. Submicron crystalline lanthanum chromite was prepared by the
autoignition of a citrate- nitrate gel. The effect of the fuel- oxidant
molar ratio and sample form prior to combustion was investigated in terms
of phase formation, particle size, morphology, and agglomerate formation.
Various characterization methods, including X-ray powder diffraction and
thermal analysis, scanning electron microscopy and BET measurement, were
used to evaluate powder characteristics. It was shown that the reaction
period depends on the fuel/oxidant ratio and reaction mixture packing.
The lanthanum chromite powders prepared via the combustion route exhibited
surface areas of about 12 m2/g for the loose packed layer prepared
samples and 8.8 to 13 m2/g for the samples prepared from a pellet.