Study On Axial Electromechanical Properties And Oxygen Diffusion Characteristics Of The Second Generation Hts Tape Joints

The second generation high temperature superconducting tape using ReBCO material,also called coated conductors,has great prospect for application in medical,military,energy and many other fields,because of its high critical current density,good performance in magnetic field and low cost.Due to the constraints of production scale and preparation process,it is still a difficult task to produce high-quality kilometer-level single tape.Therefore,the joining technical is of great value to combine several tapes into a unity.At present,there are non-superconductiong joints and superconducting joints.For non-superdoncuting joints there are several different technicals such as soldering,silver diffusion and other methods.Soldering method developed rapidly due to its earlier start and easier process.However,silver diffusion joint has relatively fewer researches because of its close invention time.For superconducting joint technique,because of the hard manufacturing process and less experience,the progress is rather slow,so far only 4 reports in the world presented their achievements in that field.In this paper,the silver diffusion joint manufactured by CC tapes offered by Shanghai Superconductor Technology Corporation and the behavior of oxygen diffusion in superconducting joint making process,is respectively studied.For silver diffusion joints,the fabrication process of the joint,the mechanical properties and failure mechanism of the joint under axial tension,and the solution to the problem that the joint performance is weaker than that of the single tape,are clearly reported,which provided the basis for improving the application of silver diffusion joint.The oxygen content is a key factor to determine the properties of YBCO thin films.To study the behavior of oxygen diffusion in superconducting joint manufacturing process,a simulation model was established and applied to superconducting joint models with different micro-structures,by which the relationship between oxygenation time and resistance of superconducting joint was obtained.Finally,the micro-processing of the superconducting layer was explored,which laid the foundation for the subsequent microstructure processing of superconducting layer.