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Synthesis and 2-Dimensional Modeling of Self-Propagating High-Temperature Synthesis of La0.6Sr0.4MnO3

Sidney Lin, Jiri Selig, and Lauren Griffin. Chemical Engineering Department, Lamar University, P.O. Box 10053, Beaumont, TX 77710

La0.6Sr0.4MnO3, a cathode material for solid oxide fuel cells, was prepared by Self-propagating High-temperature Synthesis (SHS) from a mixture of La2O3, Mn, Mn2O3, and SrO2, under oxygen atmosphere:

0.3 La2O4 + 0.4 SrO2 + 0.75 Mn + 0.125 Mn2O3 + 0.4625 O2 → La0.6Sr0.4MnO3

Reaction temperature and velocity of combustion front movement were recorded to estimate activation energy and other kinetic parameters for this reaction system. The calculated activation energy was 35 kJ/mol. Samples were taken from various stages of reaction to study the reaction mechanism. Thermal analysis (TG/DSC), X-ray diffraction, and SEM analysis were used to characterize the SHS process and product purity. Powders prepared by SHS were also compared with commercial powders.

A finite element model using the calculated activation energy and kinetic data was developed to simulate the temperature and reaction rate inside the pellet. The calculated results were verified by the experimental data. Developed model was also used to study the reaction process inside the pellet in detail, which is difficult to achieve by experiments.

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