Patent ID: 7364713

Claim:
A method for manufacturing a raw material powder for molding an oxide ion conductor composed of a multi-component metal oxide represented by the following general formula: (Ln 1-x A x )(B 1-y Fe y)O 3 where Ln is at least one selected from the group consisting of lanthanum and lanthanides, A is at least one selected from the group consisting of Sr, Ca, and Ba, B is at least one selected from the group consisting of Ga, Ti, Ni, Cu, Co, and Mg, 0<x<1, and 0≦y≦1, the method comprising: preparing a mixed powder composed of metal compounds so as to contain an oxide of Ln; an oxide of Fe if needed; an oxide and/or salt of the metal A; and an oxide and/or salt of the metal B if needed; prefiring said powder; and expanding at least some particles in said prefired powder by exposing said prefired powder to moist gas and by heating at about 50 to 200° C. until there is substantially no further change in the weight of said prefired powder in moist gas.