Method for preparing superconducting layer of high-temperature superconducting coated conductor by depositing fluorine-free chemical solution

Abstract

The invention discloses a method for preparing a superconducting layer of a high-temperature superconducting coated conductor by depositing fluorine-free chemical solution. The method comprises the following steps of: a, preparation of precursor solution; b, the preparation of coating colloid; c, coating and drying; d, wet-type decomposition heat treatment, namely placing a substrate with a film into a tubular finance; rising the temperature to be between 100 and 150 DEG C from room temperature at the speed of 1-5DEG C / min under the protection of an argon atmosphere; introducing a mixed gas of water vapor and argon with the dew point of between 10 to 20 DEG C into the furnace to form a wet argon protective atmosphere; rising the temperature to be between 450 and 500 DEG C at the speed of 0.25 to 1.5DEG C / min; keeping the temperature for 0.5 to 2 hours; cooling to the room temperature in the argon atmosphere; and e, phase formation and heat treatment to obtain the superconducting layer. The critical current density of the superconducting layer of the high-temperature superconducting coated conductor prepared by the method is up to the same magnitude order as the that of the superconducting layer prepared by a fluorine-containing method; the superconducting layer has a high-degree biaxially texture and a flat and dense surface; and the method is easy to prepare a thicker superconducting layer and has the characteristics of low cost, simple process and suitability of large-scale industrial production.

Description

technical field [0001] The invention relates to a method for preparing a superconducting layer of a high-temperature superconducting coated conductor. Background technique [0002] High-temperature superconducting coated conductors, that is, second-generation high-temperature superconducting strips, have high critical current density and irreversible field, and have great application prospects in power systems, transportation, military affairs, and medicine. The high-temperature superconducting coated conductor is mainly composed of a metal substrate, a buffer layer and a superconducting layer; the superconducting layer is an important part of the coated conductor structure as a channel for transmitting superconducting current. [0003] The existing methods for preparing the superconducting layer of the high-temperature superconducting coating conductor mainly include the vacuum continuous deposition method represented by the pulsed laser deposition method (PLD) and the trif...

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Problems solved by technology

However, the critical current density of the superconducting layer prepared by the traditional fluorine-free method is less than 1MA / cm 2 , which is an order of magnitude lower than the critical current density of the superconducting layer prepared by the fluorine-containing method, which greatly limits the application of the fluorine-free method

After analysis, this is mainly because the traditional fluorine-free method is easy to generate BaCO during the decomposition heat treatment process of preparing the superconducting layer. 3 , while BaCO 3 It is difficult to decompose during the high-temperature phase formation process and is easy to accumulate at the grain boundary of the rare earth barium copper oxide superconducting layer to hinder the transmission of superconducting current, thereby greatly reducing the current-carrying performance of the superconducting layer.

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