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US 5,352,657 AGranted
Bismuth system oxide superconductors and preparation thereof
AssigneeDaikin Industries, Ltd.
InventorsUtako Endo, Satoshi Koyama, Kazuo Okamura, Tomoji Kawai, Koichi Kitazawa
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Abstract
A bismuth system oxide superconductor comprising the 110 K phase is effectively prepared by a process comprising the steps of mixing a bismuth compound, a strontium compound, a calcium compound, a copper compound and optionally a lead compound, optionally provisionally sintering the mixture, and sintering the mixture.
Claims13
A process for producing a bismuth system oxide superconductor, which comprises
- mixing a bismuth compound, a strontium compound, a calcium compound, and a copper compound, and
- sintering the mixture in an atmosphere that has an oxygen partial pressure in the range of 0.01 to 0.15 atm.
A process for producing a bismuth system oxide superconductor, which comprises the following steps:
- (1) heating an aqueous solution which comprises bismuth nitrate, strontium nitrate, calcium nitrate and copper nitrate until dry;
- (2) heating the dried nitrate compounds produced in step (1) at a temperature sufficiently high so as to decompose said nitrate compounds and liberate NO.sub.2 and for a sufficient duration so that no further NO.sub.2 is liberated;
- and
- (3) sintering the mixture produced in step (2) in an atmosphere form a bismuth system oxide superconductor.
1 more element
Dependencies are inferred from the claim text.