A NOVEL METHOD FOR THE SYNTHESIS OF PEROVSKITE-TYPE MIXED-METAL OXIDES BY THE INVERSE MICROEMULSION TECHNIQUE

Nanoparticles of lanthanum-nickel, lanthanum-copper and barium-lead ox alates with the metal molar ratios of 1:1, 2:1 and 1:1, respectively, have been successfully synthesized in inverse microemulsions. These me ta I oxalate particles of a bo ut 20 nm diameter were readily calcined into single-phase perovskite-type LaNiO3, La2CuO4 and BaPbO3. The cal cination temperatures for these metal oxalates were generally 100-250 degrees C lower than those for the metal oxalates prepared by the conv entional aqueous solution precipitation method. The substantial reduct ion in the calcination temperatures is attributed to the formation of uniform, near-spherical nanoparticles of the metal oxalate precursors obtained by the unique inverse microemulsion technique.