摘要:
The present invention relates to a process for preparing a high-T.sub.c superconductor as a precursor material for the oxide-powder-in-tube method, which involves mixing the oxides of the elements Bi, Sr, Ca and Cu and completely melting them at temperatures of .gtoreq.1000.degree. C., then casting the melt onto a substrate which is kept at room temperature, and disintegrating the cooled melt block and grinding it into a powder.
摘要:
To produce a high-temperature superconductor of the composition Bi.sub.2 (Sr,Ca).sub.3 Cu.sub.2 O.sub.8+x having a strontium to calcium ratio of 5:1 to 2:1 and a value of x between 0 and 2, the oxides and/or carbonates of bismuth, strontium, calcium and copper are vigorously mixed in a stoichiometric ratio. The mixture is heated at a temperature of 870.degree. to 1100.degree. C. until a homogeneous melt is obtained. The melt is poured into mold and allowed to solidify in them. The cast bodies removed from the molds are annealed for 6 to 30 hours at 780.degree. to 850.degree. C. Finally, the annealed cast bodies are treated for at least 6 hours at temperatures of 600.degree. to 820.degree. C. in an oxygen atmosphere. The cast bodies can be converted into shaped bodies of the desired sizes by mechanical processes before they are annealed. The shape and size of the shaped bodies may also be determined by the shape and dimensioning of the mold used in producing the cast bodies.
摘要:
In the process for producing molded bodies from precursors of oxidic high-temperature superconductors a copper mold of the desired shape which encloses a solidified bismuth strontium calcium cuprate melt is treated with a solution of a soluble compound containing sulfate anions, an aqueous mineral acid and an oxidizing agent until the copper mold is dissolved. A protective layer of at least one of strontium sulfate or calcium sulfate is formed on the solidified melt.
摘要:
In the process for producing molded bodies from precursors of oxidic high-temperature superconductors of the BSCCO type, a copper mold of the desired shape which encloses a solidified bismuth strontium calcium cuprate melt is wired as anode in a direct current circuit composed of anode, cathode and an electrolyte, a dilute sulfuric acid is used as electrolyte and the electrolyte is subjected to a direct current of 1 to 50 mA.cm.sup.-2 until the copper mold wired as anode is dissolved and the BSCCO molded body is laid bare.
摘要:
Process for preparing a high-T.sub.c superconductor as a precursor material for the oxide-powder-in-tube method (OPIT). The present invention relates to a process for preparing a high-T.sub.c superconductor as a precursor material for the oxide-powder-in-tube method, which involves mixing the oxides of the elements Bi, Sr, Ca and Cu and completely melting them at temperatures of >1000.degree. C., then casting the melt onto a substrate which is kept at room temperature, and disintegrating the cooled melt block and grinding it into a powder.
摘要:
To produce tubular molded parts made of high-temperature superconductor oxide material based on bismuth, calcium, strontium and copper, a homogeneous melt of the oxide with a specified stoichiometry is allowed to run at temperatures of 900.degree. to 1100.degree. C. into a casting zone rotating about its horizontal axis. The solidified molded part is removed from the casting zone and it is annealed for 4 to 150 hours at 700.degree. to 900.degree. C. in an oxygen-containing atmosphere. A plant for producing tubular molded parts includes a rotatably arranged mold (4, 9) which is provided at least at one end face with a front plate 6 which reduces its free cross section, a runner 7 extending into the interior of the mold (4, 9) and a crucible 8 arranged above the runner 7 which is capable of feeding the runner 7 with melt (cf. FIG. 2 A).
摘要:
The invention relates to a high-temperature superconductor composed of the oxides of bismuth, strontium, calcium and copper and, optionally, of lead, and having the composition Bi.sub.2-a+b+c Pb.sub.a (Sr, Ca).sub.3-b-c Cu.sub.2+d O.sub.x, where a=0 to 0.7; b+c=0 to 0.5; d=-0.1 to 0.1 and x=7 to 10 and a Sr:Ca ratio of 2.8:1 to 1:2.8 as well as of strontium and/or barium sulfates. Said superconductor can be prepared by intimately mixing the oxides of bismuth, strontium, calcium and copper and optionally of lead with strontium and/or barium sulfates, melting the mixture by heating to temperatures of 870 to 1300.degree. C., higher temperatures being required for higher strontium and/or barium sulfate contents, pouring the melt into molds and allowing it to solidify slowly therein and subjecting the moldings removed from the molds to a heat treatment at temperatures of 700 to 900.degree. C. in an oxygen-containing atmosphere.
摘要翻译:本发明涉及由铋,锶,钙和铜的氧化物和任选的铅组成的具有Bi 2-a + b + c Pba(Sr,Ca)3-bc Cu 2+的组成的高温超导体, d Ox,其中a = 0至0.7; b + c = 0〜0.5; d = -0.1至0.1和x = 7至10,Sr:Ca比为2.8:1至1:2.8,以及锶和/或硫酸钡。 所述超导体可以通过将铋,锶,钙和铜的氧化物和任选的铅与锶和/或硫酸钡紧密混合来制备,通过加热至870至1300℃的温度将该混合物熔化,需要较高的温度 较高的锶和/或硫酸钡含量,将熔体注入模具中并使其在其中缓慢固化,并使在模具中除去的模制品在含氧气氛中在700-900℃的温度下进行热处理。
摘要:
Method for joining parts of ceramic high-temperature superconductor material of the composition Bi.sub.(2+a-b) (Sr.sub.1-c) Ca.sub.c) .sub.(3-a) Pb.sub.b Cu.sub.(2+d) O.sub.x, where a is 0 to 0.3, b is 0 to 0.5, c is 0.1 to 0.9 and d is 0 to 2 and x has a value depending on the state of oxidation of the metals present, the end faces of the parts located at a gap spacing apart from one another are heated by means of a fuel gas/oxygen flame to temperatures from 750.degree. to 875.degree. C. Simultaneously, a rod of the same material above the spacing gap is heated until the melt thereof drips off into the gap between the end faces of the two parts, completely filling the gap. At least the joint region between the two parts is then heat-treated for 7 to 100 hours at temperatures between 780.degree. and 850.degree. C.
摘要:
To produce a high-temperature superconductor of the composition Bi.sub.(2+a) (Sr.sub.(1-b) Ca.sub.b).sub.(3-a) Cu.sub.(2+c) O.sub.(8+x), where a is from 0 to 0.3, b is from 0.1 to 0.9 and c is from 0 to 2, and x has a value which depends on the oxidation state of the metals contained, oxides and/or carbonates of bismuth, strontium, calcium and copper are thoroughly mixed. In this process, the copper compound is used as a mixture of copper(I) oxide and copper(II) oxide. Then the mixture of oxides and/or carbonates is first allowed to react mutually in an inert gas atmosphere at temperatures from 700.degree. to 800.degree. C. for 0.5 to 36 hours before subsequently treating the mixture in an oxygen-containing atmosphere at temperatures from 700.degree. to 875.degree. C. for 3 to 60 hours.
摘要:
To produce a high-temperature superconductor of the composition Bi.sub.2 (Sr,Ca).sub.3 Cu.sub.2 O.sub.8+x having a strontium to calcium ratio of 5:1 to 2:1 and a value of x between 0 and 2, the oxides and/or carbonates of bismuth, strontium, calcium and copper are vigorously mixed in a stoichiometric ratio. The mixture is heated at temperatures of 870.degree. to 1100.degree. C. until a homogeneous melt is obtained. The melt is poured into molds and allowed to solidify in them. The cast bodies removed from the molds are annealed for 6 to 30 hours at 780.degree. to 850.degree. C. Finally, the annealed cast bodies are treated for at least 6 hours at temperatures of 600.degree. to 820.degree. C. in an oxygen atmosphere.The cast bodies can be converted into shaped bodies of the desired sizes by mechanical processes before they are annealed.The shape and size of the shaped bodies may also be determined by the shape and dimensioning of the molds used in producing the cast bodies.