Superconductor fiber refers to the fiber composed of superconductor with high critical temperature Tc, high critical magnetic field HCZ and high current density JC. Superconductors mainly include two categories, namely solid alloys with ductility and brittle metal intercompounds with crystal structure. At present, the first type is widely used. For example, niobium titanium alloy superconductor fibers containing 60% ~ 70% titanium. It is a composite structure composed of multiple alloy filaments arranged in copper matrix. In one such fiber with a diameter of 0.64mm and based on copper matrix, there are 1,345 niobium titanium alloy filaments.
The development of a high density superconductor fiber, it used the material is a kind of M, Ba and Cu ternary mixtures of superconducting oxides, its molecular formula can be summarized as: MBa2Cu3, where x is from the value of 6.5 ~ 7.0, M from yttrium, neodymium, samarium, Yong, dysprosium, holmium, erbium, thulium, ytterbium and lutetium of gens element selected, and the dispersed, spinning, chemical homogeneous amorphous metal. In superconducting oxides, the atomic ratio of M∶Ba∶Cu is 1∶2∶3. When the fiber. MbA2Cu3 is dispersed in an organic polymer soluble in organic solvents. The weight ratio of the dispersed components should be at least 70% or more. The ideal combination of the matrix polymer and its solvent is: polyethylene - xylene, polystyrene - xylene, polyurethane - dimethyl acetamide. After the superconducting oxides are mixed, dried and calcined, and then extruded and spun by screw, the resulting fibers are then treated with high temperature and solvent removal at over 1000℃. The result is a superconducting fiber with a fairly large critical current density and low combustibility. At 77K, the high critical current density of the fiber can reach about 100A·s/cm2. Because of these superior properties, superconducting fiber is increasingly being paid attention to, such as it can be used in high magnetic field device magnetic materials and excellent performance of the transmission line.
