Journal of Materials Science, Vol.34, No.6, 1163-1167, 1999
Preparation and characterization of perovskite ceramic powders by gelcasting
Perovskite La0.6Sr0.4Co0.8Fe0.2O3-delta (LSCF) powders have been successfully synthesized from oxide and carbonates based on the principle of gelcasting. Phase-forming temperature is very dependent on the ball-milling process during the suspension preparation. As the ball-milling time is increased, the temperature of phase formation decreases, therefore the perovskite powder obtained has a larger Brunaver-Emmett-Teller (BET) specific surface area. The grain sizes were around 1 mu m at 1000 degrees C and 2 mu m at 1100 degrees C from scanning electron microscopy (SEM) photographs. The perovskite powders have good sinterability: the sintering densities of ceramic bodies shaped with as-prepared powders were investigated. SEM photos show that sintered ceramics exhibit a well defined morphology in the packing and sintering of particles. The oxygen permeance of disc shaped samples, with a thickness ranging from 1.02 to 1.98 mm was 6.39 x 10(-8) - 1.99 x 10(-8) mol cm(-2) s(-1) at 900 degrees C indicating that LSCF ceramics have high oxygen permeation. It can be concluded that gelcasting is a simple and effective method for preparing practical multicomponent perovskite powders.