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US 4,208,475 AGranted
Method of forming sodium beta-Al.sub.2 O.sub.3 solid materials
AssigneeWestinghouse Electric Corp.
InventorsDeborah M. Paruso, Bulent E. Yoldas
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Abstract
A liquid polymer is formed in a low temperature polymerization reaction involving organo-metallic sodium and aluminum compounds, at least one of which is partially hydrolyzed. The polymer is hydrolyzed, dried to form an amorphous sodium Beta-alumina precursor, and then heated, at between 1,200.degree. C. and about 1,550.degree. C., to form a ceramic, comprising ion-conductive sodium Beta-alumina which is useful as a solid electrolyte.
Claims10
A method of making a highly ion-conductive ceramic material, which comprises the steps of:
- (A) reacting, in a liquid solvent medium, a first partially hydrolyzed alkoxide compound selected from the group consisting of partially hydrolyzed sodium alkoxide and partially hydrolyzed aluminum alkoxide, with an organo-metallic compound selected from the group consisting of (a) an alkoxide compound selected from the group consisting of sodium alkoxide and aluminum alkoxide, where the metal ion of the second alkoxide compound is different from the metal ion of the first partially hydrolyzed alkoxide compound, and (b) a second partially hydrolyzed alkoxide compound selected from the group consisting of partially hydrolyzed sodium alkoxide and partially hydrolyzed aluminum alkoxide, where the second partially hydrolyzed alkoxide compound is different from the first partially hydrolyzed alkoxide compound;
- so that a Na compound is reacted with an Al compound to form alcohol and a liquid polymer containing Na and Al,
- (B) hydrolyzing carbon containing organic groups in the polymer, to provide a mixture of alcohols and a hydrolyzed polymer,
- (C) removing alcohol from the mixture formed in step (B) to provide an amorphous sodium Beta-alumina precursor, and
- (D) heating the amorphous sodium Beta-alumina precursor for a time and at a temperature effective to cause a phase change and formation of a crystalline ceramic material comprising sodium Beta-alumina, where in step (A) the Na compound and the Al compound are added in an amount effective to provide a mole ratio of Na:Al of from 1:5 to 11 in the final crystalline ceramic formed after heating in step (D).
2 more elements
A method of making a highly sodium ion-conductive ceramic body, useful as a solid electrolyte, by the steps of:
- (A) reacting, in a liquid alcohol medium, a first alkoxide compound selected from the group consisting of Na(OR) and Al(OR).sub.3, where R is an alkyl group containing from 1 to 6 carbon atoms, with an amount of water effective to leave a substantial number of (OR) groups unreacted and form a first partially hydrolyzed alkoxide compound, and then
- (B) reacting, in a liquid alcohol medium, the first partially hydrolyzed alkoxide compound with an organo-metallic compound selected from the group consisting of a second alkoxide compound selected from the group consisting of Na(OR) and Al(OR).sub.3, where R is an alkyl group containing from 1 to 6 carbon atoms, where the second alkoxide compound is different from the first alkoxide compound, and (b) a second partially hydrolyzed alkoxide compound formed by the reaction, in a liquid alcohol medium, of a second alkoxide compound selected from the group consisting of Na(OR) and Al(OR).sub.3, where R is an alkyl group containing from 1 to 6 carbon atoms with an amount of water effective to leave a substantial number of (OR) groups unreacted, where the second partially hydrolyzed alkoxide compound is different from the first partially hydrolyzed alkoxide compound;
- so that a Na compound is reacted with an Al compound to form alcohol and a liquid polymer containing Na and Al, and then
- (C) adding an amount of water to the polymer effective to hydrolyze carbon containing organic groups in the polymer, to provide a mixture of alcohols and a hydrolyzed polymer, and then
- (D) removing alcohol from the mixture formed in step (C) to provide an amorphous sodium Beta-alumina precursor, and then
- (E) heating the amorphous sodium Beta-alumina precursor at between 1,200.degree. C. and about 1,550.degree. C., to cause a phase change and formation of a crystalline ceramic material consisting essentially of sodium Beta-alumina, where in step (B) the Na compound and the Al compound are added in an amount effective to provide a mole ratio of Na:Al of from 1:5 to 11 in the final crystalline ceramic formed after heating in step (E), and then
- (F) forming the ceramic material into a suitable shape, and finally
- (G) sintering the formed ceramic at a temperature and for a time effective to provide a consolidated, solid, sodium ion-conducting electrolyte body.
5 more elements
Dependencies are inferred from the claim text.