Charge generation during the synthesis of doped lanthanum manganites via combustion of organo-inorganic precursors

Abstract

Complex oxides on the basis of LaMnO3±y were obtained via combustion of precursors containing nitrates and soluble organic agents (polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, polyethylene glycol, cellulose; glycine, glycerine and citric acid). The phenomenon of charge generation processes during the synthesis was analysed by measuring the potential difference between the ground and precursor. It was proposed that one of the main factors determining the processes of charge generation is the release of gaseous molecular charged particles into the environment. The maximum value of generated charges was fixed for polyvinyl alcohol containing precursors and the lowest for glycine containing ones. The composition of the initial precursors (used organic component and the ϕ value) effects the maximum temperature achieved during synthesis (300 °C–1100 °C), concentration of released gases (50–600 ppm (CO), 250–2800 ppm (NO)) and the potential difference between the ground and precursor. The dependence of specific surface area (7.5–21 m2/g), the temperature of the beginning of the intense sintering (750 °C–1150 °C) and the maximum achievable shrinkage (5–21%) on the value of measured potential difference in precursors was shown. The established regularities allow expanding ability for the production of complex oxide materials with the specified properties.