A sintering method for an oxide superconducting powder rod and a method for preparing a superconducting wire rod by using the powder rod sintered by using the sintering method

A sintering method and technology for superconducting wire rods, which are used in cable/conductor manufacturing, electrical components, circuits, etc. to achieve the effects of low defect rate, high critical current density, and high filling factor

Active Publication Date: 2013-04-24
INNOVA SUPERCONDUCTOR TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

An object of the present invention is to solve defects such as moisture and residual gas produced by the precursor powder in the process of preparation, pretreatment and filling of metal sleeves when preparing long superconducting wires. The process of sintering the superconducting powder is specifically to increase the density of the precursor powder by isostatic pressing to form a powder rod, especially before the powder rod is loaded into a tube, the powder rod is subjected to variable temperature and variable rate sintering treatment under a controlled atmosphere, To remove all the carbon, nitrogen and hydroxyl components compounded in the powder rod, as well as the carbon dioxide, water and air adsorbed on the surface of the powder, to form a rod with a suitable proportion of tetragonal and orthorhombic crystal structure Bi2212 as the main phase Phase composition, to realize the object of the present invention

Method used

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  • A sintering method for an oxide superconducting powder rod and a method for preparing a superconducting wire rod by using the powder rod sintered by using the sintering method
  • A sintering method for an oxide superconducting powder rod and a method for preparing a superconducting wire rod by using the powder rod sintered by using the sintering method

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Effect test

Embodiment 1

[0031] The superconducting precursor powder referred to in the present invention contains five metal elements of bismuth, lead, strontium, calcium and copper and has a stoichiometric ratio Bi:Pb:Sr:Ca:Cu=1.9:0.3:2:2.1:3 Superconducting powder prepared by solid state reaction method or spray drying method.

[0032] Using the above superconducting precursor powder as raw material, according to figure 1 The method steps shown in the flow chart of manufacturing oxide superconducting wires are to prepare Bi2223 superconducting wires. The first is the pretreatment of the precursor powder. Specifically, the precursor powder is roasted at 800°C in the atmosphere for 10 hours, and then ground to reduce the particle size of the powder to 1-2 μm. The phase composition of the powder after pretreatment is Bi2212(Bi2Sr2Ca1Cu2Ox) The main phase contains a small amount of CaPbO4, 3321, CuO, 14:24AEC, 1:1AEC and other second phases. Then the powder is pressed into a powder rod with a diamete...

Embodiment 2

[0035] Obtain powder rod by the method identical with embodiment 1, carry out powder rod sintering then, control atmosphere in the furnace is 5% O2 / N2 balance gas, with the rate of 100 DEG C / hour heating up, be 400 DEG C to T1 and carry out insulation, The holding time t1 is 2 hours. After the holding time, until 800°C, use V1 to raise the temperature at a rate of 200°C / hour, and at 800°C, keep holding time t2 for 5 hours, then cool down to 500°C at 200°C / hour, and The atmosphere in the furnace is switched to 99.999% high-purity oxygen, and then the temperature is lowered to 100°C at 600°C / hour, and the furnace is taken out, and then single-core, multi-core drawing, preliminary rolling and deformation heat treatment are carried out according to the same follow-up steps as in Example 1. Made (Bi, Pb) 2223 high temperature superconducting tape.

Embodiment 3

[0037] According to the same method as in Example 1, the powder rods were prepared, and then the powder rods were sintered. The atmosphere in the furnace was controlled to be 8.5 O2 / N2 balance gas, and the temperature was raised at a rate of 100°C / hour, and the temperature was kept at 300°C until T1 was kept. The time is 5 hours. After the heat preservation is over, until 800°C, use V1 to raise the temperature at a rate of 100°C / hour, and keep it at 800°C for 5 hours, then cool down to 650°C at 200°C / hour, and switch the atmosphere in the furnace to 99.999 % of high-purity oxygen, then cooled to 100°C at 600°C / hour, and then released from the furnace, and then carried out single and multi-core drawing, preliminary rolling and deformation heat treatment according to the same subsequent steps as in Example 1 to make (Bi, Pb) 2223 high temperature superconducting tape.

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Abstract

The invention relates to a sintering method for an oxide superconducting powder rod, and the concrete method comprises performing sintering treatment at variable rate and variable temperature to the powder rod before tube loading under controlled atmosphere. The invention also relates to a method of preparing a superconducting wire rod, the method comprises treatment steps used for preparing superconducting powder before the tube loading, and the superconducting powder before the tube loading comprises: performing pretreatment to precursor powder, and specifically, performing a step of high temperature sintering, a step of grinding and drying, and a step of pressing into powder rods to the precursor powder, and then performing the step of sintering treatment at variable rate and variable temperature to the powder rod before tube loading under controlled atmosphere. The method for preparing a superconducting wire rod of the present invention enables the superconducting wire rod to have a relatively high filling factor, a high critical current density, uniform performance, and a low defect rate, and the method is particularly suitable for preparation of industrial long superconducting wire rods.

Description

technical field [0001] The present invention relates to a precursor powder of an oxide superconducting wire, a method for manufacturing the precursor powder, and an oxide superconducting wire manufactured using the precursor powder. The manufacturing technology of superconducting precursors with high packing density and reactivity, uniform phase composition, high density and easy subsequent machining deformation before the wire is loaded into the tube. Background technique [0002] Bi-based high-temperature superconducting wire is the only high-temperature superconducting material that can be produced on a large scale in the world today. It is widely used in high-temperature superconducting cables, high-temperature superconducting motors, high-temperature superconducting current limiters and high-temperature superconducting current leads. In the development process of other application products. Usually (Bi, Pb)-2223 oxide superconducting wire is manufactured by powder tube...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/64H01B13/00
Inventor 宋秀华
Owner INNOVA SUPERCONDUCTOR TECH
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