Experimental Analysis On The Properties Of High Temperature Superconducting Coated Conductors Under Mechanical-Electro Fields

High temperature superconducting(HTS) coated conductors because of its high transition temperature, excellent current carrying capacity under high field and shape workability has become one of the hot topics in the application of superconductivity. It has a wide application prospect in energy, electric transport, materials and other fields. In these applications, superconductors always operate in a complex environment that has low temperature, high magnetic field and large current. The superconductors or the structure itself suffer huge electromagnetic force and this will lead to its structural deformation, thus leading to the properties degradation of superconductors, especially the critical current degradation. These will have a serious impact on the safe, reliable and stable operation of superconducting devices.Thus, for the YBCO Coated Conductor(YBCO CC) which is one of the current international research focus, to study a behavior of its critical current as a function of deformation has very important scientific significance whether from the national demand or the frontiers of science. The Current carrying capacity, mechanical properties and V-I characteristics curves of YBa2Cu3O7-x Coated Conductor with different axial tension loads at 77 K, self-field are investigated in this thesis.Firstly, the critical current and the mechanical properties of the first generation Bi2223 HTS tapes with different axial tension loads at 77 K,self-field are measured. The experimental results show that Ni-Cr alloy layer has no effect on the current transmission property of Bi2223 HTS tapes.Also, it has no contribution to the critical current degradation of Bi2223 HTS tapes. But the Ni-Cr alloy layer can significantly improve the permissible axial tension load range of Bi2223 HTS tapes, this improvement of axial tension load as a function of the thickness of Ni-Cr alloy layer shows a linear relationship.secondly, the V-I characteristic curves and the n value of YBa2Cu3O7-x Coated Conductor with different axial tension strain at 77 K, self-field are measured. The experimental results show that with the increasing of the axial tensile strain,the voltage mutations of V-I characteristic curves will move, but the change of the n value is very small in material’s elastic region.Finally, a formula was firstly given to correct the V-I characteristic curves of YBa2Cu3O7-x Coated Conductor by fitting of the experimental data. In addition, the n value of YBa2Cu3O7-x Coated Conductor as a function of axial tension strain was given through the formula. By comparison with experimental data, the V-I characteristic curves and the n value of YBa2Cu3O7-x Coated Conductor with arbitrary axial tension strain at 77 K, self-field can be given by our formula, also the critical current of YBa2Cu3O7-x Coated Conductor with reversible strain.