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US 5,744,427 AGranted
Thallium oxide superconductor and method of preparing the same
AssigneeSumitomo Electric Industries, Ltd.
InventorYasuko Torii
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Abstract
In a method of preparing a thallium oxide superconductor having components of Tl-Bi-Ca-Sr-Cu-O or Tl-Bi-Pb-Ca-Sr-Cu-O from raw material powder, the raw material powder is subjected to first heat treatment, then exposed to a compressive load, and thereafter subjected to second heat treatment. Thus, a thallium oxide superconductor having a high critical current density can be obtained.
Claims13
A method of preparing a thallium oxide superconductor, comprising the steps of:
- providing a thallium oxide raw material powder;
- providing a sheath of metal from the group consisting of silver and silver alloy;
- sintering said thallium oxide raw material powder, thereby providing a thallium oxide superconductive material;
- filling said sheath with said thallium oxide superconductive material thereby providing a wire;
- deforming said wire into a tape consisting of said thallium oxide superconductive material surrounded by said metal;
- performing a first heat treatment on said thallium oxide superconductive material and said metal of said tape at a temperature between about 700.degree. C. and about 920.degree. C., then
- applying a compressive load to said metal and said thallium oxide superconductive material of said tape;
- and then
- performing a second heat treatment on said thallium oxide superconductive material and said metal of said tape at a temperature between about 750.degree. C. and about 870.degree. C., wherein said temperature of said first heat treatment is higher than said temperature of said second heat treatment.
6 more elements
A method of preforming a thallium oxide superconductor comprising the steps of:
- providing a thallium oxide raw material powder;
- providing a metal sheath;
- sintering said thallium oxide raw material powder, thereby providing a thallium oxide superconductive material;
- filling said sheath with said thallium oxide superconductive material, thereby providing a wire;
- applying a first compressive load to said wire, thereby deforming said wire into a tape consisting of said thallium oxide superconductive materials surrounded by said metal;
- performing a first heat treatment on said thallium oxide superconductive material and said metal of said tape at a temperature between about 700.degree. C. and about 920.degree. C., then
- applying a second compressive load to said metal and said thallium oxide superconductive material of said tape, thereby providing said tape with a final thickness;
- and then
- performing a second heat treatment on said thallium oxide superconductive material and said metal of said tape at a temperature between about 750.degree. C. and about 870.degree. C., wherein said temperature of said first heat treatment is higher than said temperature of said second heat treatment, and wherein said temperature of said second heat treatment satisfies the following numeral condition:
- T=840+A.times.W-10t
- where 700.ltoreq.T.ltoreq.880, 600.ltoreq.A.ltoreq.1000, W=the amount of millimeters of said final thickness, and t=the amount of hours for which the second heat treatment is performed.
8 more elements
Dependencies are inferred from the claim text.