Electrically conductive mixed oxide prodn. by reactive spray drying - of mixed oxide of lanthanum with manganese, nickel, or cobalt contg. chromium and small amts. of other metal cations

摘要

Prodn. of electrically conductive oxidic material (I) for application at high temp. and in a wide range of O2 partial pressures involves adding small amts. of Cr and mono- or di-valent alkali, alkaline earth, Zn, Cd, Mn, Sn and/or Pb cations to mixed oxides with perovskite structure based on LaMnO3, LaNiO3 or LaCoO3. A soln. of the cations in the exact stoichiometric ratio is sprayed into a hot reaction tube at 1000-1500 K, together with or with injection of the O2 needed for the reaction, and the solvent is vapourised. The non-volatile constituents pass through the tube, where the desired (I) with homogeneous distribution forms in the hot reaction zone, and the powder is deposited in a cyclone, the solvent vapour being removed. (I) is useful in electrochemical high temp. cells, esp. fuel cells, and for supplying current under conditions of high temp. (hot conductors, probes etc.) and in reducing or varying gas atmos.