Solution Combustion Synthesis of La0.9Me0.1MnO3 ± y Powders in Nitrate–Polyvinyl Alcohol and Nitrate–Polyvinylpyrrolidone Systems

The processes occurring during the synthesis of lanthanum manganites doped with alkali metal ions in combustion reactions in the nitrate–polyvinyl alcohol and nitrate–polyvinylpyrrolidone systems were investigated. The maximum combustion temperatures of compositions depending on the organic fuel content φ (ratio to stoichiometric amount) were given. It was found that the maximum temperature of the process is 531°C, which is reached when synthesizing LaMnO3 ± y sample from the composition with polyvinyl alcohol (φ = 4). It was experimentally shown that the maximum combustion temperature increases with increasing organic component amount in the composition and decreasing pyrolytic impurity gas (such as carbon monoxide CO, nitrogen oxides NO and NO2) concentrations. The processes of charge generation during combustion of nitrate–polyvinyl alcohol and nitrate–polyvinylpyrrolidone systems at different types of heating of the reactor were studied. The effect of synthesis conditions on the specific surface area of complex oxides was investigated.