Method for preparing high temperature superconductive membrane by means of controlling fluorine-barium ratio of precursor

Abstract

The invention belongs to the technical field of high temperature superconductive materials, and particularly relates to a method for preparing a high temperature superconductive membrane by means of controlling the fluorine-barium ratio of a precursor. The fluorine content of the precursor used in the method is extremely low, and the molar ratio of fluorine and barium can be continuously controlled to be within 2-4. With adoption of the method, the fluorine content of the precursor can be controlled, and thus the production of a liquid phase during the heat treatment process can be controlled, so that the reaction between the precursor and a substrate or a transition layer can be prevented, the generation of a second phase related to the liquid phase can be avoided, and finally the high performance of the superconductive membrane can be ensured. Meanwhile, due to adoption of the method, barium can be completely converted into barium fluoride during the heat treatment process, so that formation of barium carbonate harmful to the performance of the superconductive membrane can be avoided. Compared with the traditional fluorine-containing chemical solution sedimentation method, the method has the advantage that the fluorine content of the precursor is significantly reduced, so that the generation of fluorine-containing gas during the heat treatment process can be reduced, the heat treatment time can be shortened and the hazard to the environment can be reduced.

Description

technical field [0001] The invention belongs to the technical field of high-temperature superconducting materials, and in particular relates to a method for preparing a high-temperature superconducting film by controlling the fluorine-barium ratio of a precursor. Background technique [0002] Rare earth barium copper oxide (REBa 1+x Cu 3 o 7-y , where RE is a rare earth element such as Y, Gd, Sm, etc., 0.5≤x≤1, 0<y<0.5) The high-temperature superconducting film is the core component of the second-generation high-temperature superconducting wire (also known as a coated conductor) part, it has a very high self-field critical current density (generally higher than 1MA / cm 2 ), and is suitable for applications in high magnetic field environments. The current technology for preparing high-temperature superconducting films mainly includes chemical solution deposition and some vacuum deposition methods. The chemical solution deposition technology is very beneficial to redu...

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Problems solved by technology

On the other hand, the introduction of fluorine in the precursors in the previous work is by using one or more trifluoroacetates, so the fluorine-to-barium ratio is fixed at several values, and it is difficult to continuously adjust to find the optimal value.

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