Self-propagating high-temperature synthesis of LaMO3 perovskitetype oxide using heteronuclearcyano metal complex precursors

Abstract

The decomposition of La[Fe(CN)6]·5H2O and La[Co(CN)6]·5H2O under different atmospheres has been analyzed by thermogravimetry (TG) and differential thermal analysis (DTA). In addition, the decomposition temperature at different sample locations was monitored for sample masses around 2 g of La[Fe(CN)6]·5H2O and La[Co(CN)6]·5H2O, when they were calcined for 1 h at temperatures ranging from 200 to 400 °C in a controlled gas-flow system. Results showed that, the large enough of the cyano complex precursors undergo combustion when they are decomposed under oxygen atmosphere. X-ray diffraction results revealed that perovskite-type oxides crystallize due to the overheating of the process. As a result, it has been possible to produce LaFeO3 and LaCoO3 perovskite-type oxide powders by SHS under oxygen atmosphere using La[Fe(CN)6]·5H2O and La[Co(CN)6]·5H2O as a precursor. The effect of the ignition temperature has been investigated. The specific surface area of the perovskite-type oxides produced via SHS using heteronuclearcyano metal complex as a precursor is significantly higher than that of other LaMO3 produced using the same technique but obtained from other type of precursors