A method for preparing bi-2212 high temperature superconducting wire

Abstract

The invention discloses a method for preparing a Bi-2212 high-temperature superconducting wire. The method comprises the following steps: step one, carrying out tabulating of Bi-2212 powder to obtaina primary composite wire; step two, carrying out primary drawing on the primary composite wire to obtain a single-core wire; to be specific, carrying out annealing at a temperature of 250 DEG C to 280DEG C during primary drawing; step three, carrying out cutting, bundling, and tabulating on a single-core wire, carrying out secondary drawing to obtain a secondary composite wire, and repeating thesteps and carrying out third drawing to obtain a Bi-2212 wire; to be specific, carrying out annealing at a temperature of 250 DEG C to 280 DEG C during the secondary drawing and third drawing; and step four, carrying out semi-molten processing on the Bi-2212 wire to obtain a Bi-2212 high-temperature superconducting wire. According to the invention, the internal stress in the wire is eliminated bymeans of low-temperature annealing during drawing, so that mechanical property difference between the Bi-2212 powder and the silver sheath as well as the unevenness of the silver super-interface of the Bi-2212 wire is reduced, the grain ordering in the core wire is improved, and the current-carrying property of the Bi-2212 wire is enhanced.

Description

technical field [0001] The invention belongs to the technical field of high-temperature superconducting wire preparation, and in particular relates to a method for preparing a Bi-2212 high-temperature superconducting wire. Background technique [0002] Bi-2212 high-temperature superconductor is the most important branch of high-temperature superconducting materials. Due to its easy processing and high current-carrying performance, Bi-2212 high-temperature superconductor has become one of the most promising high-temperature superconducting materials. [0003] At present, the preparation technology combining the powder-in-tube method (PIT) and the melting method is the mainstream technology for preparing high-performance Bi-based high-temperature superconducting wire strips. This technology is to put the superconducting precursor powder into the silver tube, and prepare the multi-core composite wire by drawing and assembling, and then process it to the designed wire strip size...

AI Technical Summary

Problems solved by technology

Conventional annealing system is an important reason for the rough silver superinterface of Bi-2212 wire

Because the Bi-2212 wire rod will have serious work hardening when it is processed to a certain extent, it must be annealed, otherwise there will be a danger of disconnection; but the annealing temperature of the conventional Bi-2212 wire rod is 400 ℃ ~ 450 ℃, and the annealing process includes The hardness of the sleeve material is from 1100N / mm 2 Reduced to 250N / mm 2 , the hardness of Bi-2212 powder does not change much and remains at 500N / mm 2 , there will be shear stress in the process of continuous processing, and these shear stress will cause silver and ceramic powders with huge differences in hardness to form roughness at the interface, resulting in a sharp decline in the current-carrying performance of the Bi-2212 wire.