Co-precipitation process for preparing superconductor powder
AssigneeMotorola, Inc.
InventorWei-Yean Howng
Life of this patent
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Abstract
A fine stoichiometric superconductor powder may be co-precipitated from the addition of appropriate metal compound powders in ammonium carbonate. The co-precipitated powder is very homogeneous because the reaction progresses in liquid solution. For example, YBa.sub.2 Cu.sub.3 O.sub.7-x superconducting powder may be prepared by the co-precipitation of yttrium oxide, copper (I) acetate, copper (II) acetate and barium acetate. The acetates precipitate by nucleating on the yttrium oxide particles. The process permits a relatively wide window of starting reactant proportions yet still produce ceramics having superconductive properties.
Claims16
A co-precipitation process for preparing a superconductor powder comprising:
- suspending an insoluble yttrium compound powder in an aqueous solution containing dissolved copper and barium salts to form a slurry,
- adding an aqueous ammonium carbonate solution to the slurry, whereupon a precipitate forms that comprises copper and barium carbonate compounds deposited onto the yttrium compound powder,
- drying the precipitate, and
- calcining the dried precipitate to form the superconductor powder.
A co-precipitation process for preparing a superconductor powder comprising
- suspending an insoluble yttrium oxide powder in an aqueous solution containing dissolved copper and barium salts to form a slurry,
- adjusting the pH of the slurry to between about 4.5 and 6.0,
- adding an aqueous ammonium carbonate solution to the slurry while maintaining the pH of the slurry between about 6.5 and 8.5, whereupon a precipitate forms that comprises copper and barium carbonate compounds deposited onto the yttrium oxide powder, and
- drying the precipitate, and
- calcining the dried precipitate to form the superconductor powder.
A superconductor powder prepared by a co-precipitation process comprising the steps of:
- suspending an insoluble yttrium compound powder in an aqueous solution containing dissolved copper and barium salts to form a slurry,
- adding an aqueous ammonium carbonate solution to the slurry, whereupon a precipitate forms that comprises copper and barium carbonate compounds deposited onto the yttrium compound powder, and
- drying the precipitate, and
- calcining the dried precipitate to form the superconductor powder.
A superconductor powder prepared by a co-precipitation process comprising the steps of
- suspending an insoluble yttrium oxide powder in an aqueous solution containing dissolved copper and barium salts to form a slurry,
- adjusting the pH of the slurry to between about 4.5 and 6.0,
- adding an aqueous ammonium carbonate solution to the slurry while maintaining the pH of the slurry between about 6.5 and 8.5, whereupon a precipitate forms that comprises copper and barium carbonate compounds deposited onto the yttrium oxide powder, and
- drying the precipitate, and
- calcining the dried precipitate to form the superconductor powder.
Dependencies are inferred from the claim text.