Studies on strontium substituted rare earth manganites

Sintering, electrical conductivity and thermal expansion behaviour of combu stion synthesised strontium substituted rare earth manganites with the gene ral formula Ln(1-x)Sr(x)MnO(3) (Ln = Pr, Nd and Sm; x = 0, 0.16 and 0.25) h ave been investigated as solid oxide fuel cell cathode materials. The combu stion derived rare earth manganites have surface area in the range of 13-40 m(2)/g. Strontium substitution increases the electrical conductivity value s in all the rare earth manganites. With the decreasing ionic radii of rare earth ions, the conductivity value decreases. Among the rare earth mangani tes studied, (Pr/Nd)(0.75)Sr0.25MnO3 show high electrical conductivity ( > 100 S/cm). The thermal expansion coefficients of Pr0.75Sr0.25MnO3 and Nd0.7 5Sr0.25MnO3 were found to be 10.2 x 10(-6) and 10.7 x 10(-6) K-1 respective ly, which is very close to that of the electrolyte (YSZ) used in solid oxid e fuel cells. (C) 1999 Elsevier Science B.V. All rights reserved.