Method of producing oxide ion conductor
AssigneeHonda Giken Kogyo Kabushiki Kaisha
InventorsSusumu Nakayama, Yoshikatsu Higuchi
Life of this patent
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Abstract
A lanthanum oxide (La2O3) powder, a germanium oxide (GeO2) powder, and a strontium carbonate (SrCO3) powder are mixed in a ratio so that a composition of the obtained composite oxide LalXm(AO4)6−n(ZO4)nOp satisfies 8≦l+m<10, 0≦m≦2, 0≦n≦2 and 0≦p≦2. Thenafter, the materials are formed and sintered to prepare an oxide ion conductor. The crystalline structure of LalXm(AO4)6−n(ZO4)nOp belongs to the apatite type structure. The conduction of oxide ion occurs when O2− 14 occupying the 2a site of the apatite type structure moves along the c-axis direction.
Claims6
A method of producing an oxide ion conductor, comprising the steps of:
- obtaining a mixed powder in which a lanthanum compound, a compound of a tetravalent element A, and at least one of a compound of a divalent or tetravalent element X and a compound of a trivalent or pentavalent element Z are mixed in a ratio to produce LalXm(AO4)6−n(ZO4)nOp provided that 8≦l+m≦9.33, 0≦m≦2, 0≦n≦2, 0≦p≦2, m+n≠0;
- forming said mixed powder to obtain a formed product;
- and
- sintering said formed product at a temperature of 1450 to 1600° C. to obtain said oxide ion conductor having a crystalline structure which belongs to an apatite type structure and having a composition formula which is represented by LalXm(AO4)6−n(ZO4)nOp provided that 8≦l+m≦9.33, 0≦m≦2, 0≦n≦2, 0≦p≦2, m+n≠0,
- wherein a Ge compound is selected as said compound of element A, a Sr compound or a Zr compound is selected as said compound of element X, and an Al compound or a P compound is selected as said compound of element Z.
A method of producing an oxide ion conductor, comprising the steps of:
- obtaining a mixed powder in which a lanthanum compound, a compound of a tetravalent element A, and at least one of a compound of a divalent or tetravalent element X and a compound of a trivalent or pentavalent element Z are mixed in a ratio to produce LalXm(AO4)6−n(ZO4)nOp provided that 8≦l+m≦9.33, 0≦m≦2, 0≦n≦2, 0≦p≦2, m+n≠0;
- heating said mixed powder at a temperature of 700 to 1200° C. to obtain a granular material of a composite oxide of lanthanum and germanium having a crystalline structure which belongs to an apatite type structure and having a composition formula which is represented by LalXm(AO4)6−n(ZO4)nOp provided that 8≦l+m≦9.33, 0≦m≦2, 0≦n≦2, 0≦p≦2, m+n≠0;
- pulverizing said granular material to obtain a composite oxide powder;
- forming said composite oxide powder to obtain a formed product;
- and
- sintering said formed product at a temperature of 1450 to 1600° C. to obtain said oxide ion conductor composed of said composite oxide,
- wherein a Ge compound is selected as said compound of clement A, an Sr compound or a Zr compound is selected as said compound of element X, and an Al compound or a P compound is selected as said compound of element Z.
Dependencies are inferred from the claim text.