Method for preparing Ba0.6K0.4Fe2As2 superconductive wire through mechanical alloying without sintering

Abstract

The invention discloses a method for preparing a Ba0.6K0.4Fe2As2 superconductive wire through mechanical alloying without sintering. The method includes the following steps of: a, proportioning Ba tablets with degree of purity of 99.5%-99.9%, K tablets and Fe powder both with degree of purity of 95%-99%, and As powder with degree of purity of 99.%-99.99% at atomic ratio of 0.6:0.4:2:2 in a glove box, and putting the mixture into a ball grinder, wherein the K tablets are overdosed by 5%-10%, the ball grinding medium is stainless steel balls, and the weight ratio of the stainless steel balls to the raw materials is (10:1)-(20:1); b, grinding the raw materials proportioned in step a in the ball grinder for 1-2hours with the rotating speed of 1,425-1,725RPM (Revolutions Per Minute) to obtain powder; c, intensively mixing the powder obtained in step c and In or Sn powder at mass ration of 5%-10% in a mortar, then loading the powder mixture into a Monel alloy tube and compressing and sealing the two ends of the alloy tube; and d, directly rolling and drawing the Monel alloy tube which contains the powder mixture into a Ba0.6K0.4Fe2As2 superconductive wire.

Description

technical field [0001] The invention relates to a method for preparing a superconducting wire, in particular to a method for preparing Ba by mechanical alloying without sintering. 0.6 K 0.4 Fe 2 As 2 method of superconducting wires. Background technique [0002] In January 2008, Hidekuma Hosono’s group at Tokyo Institute of Technology discovered a new type of iron-based superconductor LaFeAs(O,F)[1] with a superconducting transition temperature of 26K. This breakthrough opened a new round of research in the scientific community. After the upsurge of high-temperature superconductivity research, several new systems of iron-based superconductors have been discovered one after another [2-5]. The new iron-based superconductor has the value of superconducting mechanism research [6], but also has potential broad application prospects [7]. In many iron-based superconductor systems, Ba 0.6 K 0.4 Fe 2 As 2 Due to its small anisotropy, high upper critical field, and high pinni...

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Problems solved by technology

(2) Due to the soft texture of the silver sheath and the release of stress during high-temperature sintering, it is not conducive to the formation of dense superconducting wire cores

Very dense wires can be obtained using hot isostatic pressing (HIP) [10], but the process is very complex and only suitable for short samples

(3) Ba 0.6 K 0.4 Fe 2 As 2 The system contains highly oxidizable elements Ba, K and As elements. The existing process puts the wire rod in a sealed quartz tube or a high-melting point metal tube, and sinters it under the protection of high vacuum or inert gas. The process is complicated and time-consuming.

In addition, due to the very active chemical properties of K, As is a highly toxic element, there are potential safety hazards during high-temperature sintering, and higher requirements are placed on the preparation laboratory or production room

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