Study On Technic For Suoerconducting Joint Of Second Generation High Temperature Superconducting Tapes

The second generation of high temperature superconducting using ReBCO as superconducting layer,also known as coated conductors,,are considered to have enormous potential in practical applications because of its low cost on using,superior current carrying capacity and excellent magnetic field performance.However,due to its high requirements on the production process,it is still impossible to achieve rapid and stable preparation of high-quality kilometer-long tapes.Therefore,the technic of connecting short tapes by superconducting joints to produce a long tape,is of great significance to the practical use of the second generation HTS tapes.At the same time,superconducting joint technic will also make it possible to produce large magnets operating in Persistent Current Mode?PCM?using second generation HTS tapes.The world's first superconducting joint was made by a team lead by Haigun Lee,from South Korea.During its preparation,the researchers used a combination of mechanical crimping and heat treatment.Recently,a method considered promising as its process is simple and can produce joint with high performance is discovered.In this method,a GdBCO intermediate connecting layer with low melting point is deposited on tapes'superconducting layer,and then connected by heat treatment process.In this paper,superconducting tapes and substrate tapes provided by Shanghai Superconductor Technology Co.,Ltd.were used to study the critical technics in the preparation process of the superconducting joint.And a preliminary exploration on shortening the annealing time of superconducting joints by UV laser drilling Process is performed.On the critical technics of the preparing superconducting joint,YBCO intermediate connecting layer was successfully prepared on single crystal and artificial substrate by FF-MOD method.And the phase evolution of BaCO₃ and YBCO phase is systematic studied.These studies can provide theoretical and experimental basis for preparing and connecting the superconducting joints'intermediate connecting layer.On the UV laser drilling technic,this paper optimized the technical process and parameters of UV laser drilling,obtained a drilling effect that meets the actual requirements.And the influence of the drilling technic on the critical current?I_c?of the tape is studied.This study provides a technical basis for shortening the time of annealing process when prepare a superconducting joint.