The preparation method of niobium plate with wide plate width barrier layer for superconducting wire includes: 1. Niobium plate is prepared by reversing rolling the niobium sheet along one fire, and then grinding, sanding, pickling, shearing and vacuum annealing in turn; Second, the niobium plate strip is rolled by tension, and then the wide plate barrier layer niobium plate is obtained by grinding, sanding, pickling, shearing and vacuum annealing. The invention adopts the rolling method of two rolling processes and large deformation rate to make the structure of niobium material undergo large deformation, without deformation dead zone and rapid processing and forming, which reduces the influence on the surface quality of niobium plate. At the same time, combined with controlling the temperature and time of vacuum annealing heat treatment after each rolling process, the deeply deformed grains recover and completely recrystallize, forming uniform microstructure. Wide plate barrier niobium tablets with good surface quality, uniform microstructure, small average grain size, small uniform grain range and large elongation are prepared, which are suitable for large superconducting scientific devices.
Barrier layer niobium plates are mainly used to prepare NbTi and Nb3Sn superconducting filaments, and NbTi and Nb3Sn superconducting filaments are the core materials that provide strong magnetic field for the all-superconducting Tokamak fusion device of energy manufacturing equipment. Therefore, the successful preparation of barrier layer niobium plates for high-quality superconducting filaments on the one hand can improve China's international competitiveness in the field of superconductivity. On the other hand, it can provide a material basis for the manufacturing equipment of new renewable energy.
The role of barrier layer niobium sheet for high quality superconducting wire is to prevent the copper in the copper sheath from reacting with titanium to produce titanium copper compound, and to prevent the fracture of the wire in the subsequent stretching process. The requirements of the finished superconducting wire are very strict, the diameter of the wire is 100 microns, and the core wires are arranged neatly at the section of the wire after stretching, and the deformation is uniform, and the phenomenon of uneven core wire thickness does not appear. The highest critical current I value reaches 360A/mm2 at 4.2k and 5.0T, and the length of the wire is greater than 10000m. Through the above quality requirements, the work hardening index (n) of NbTi and Nb3Sn superconducting wires can meet the requirements of energy manufacturing equipment. If the barrier layer niobium sheet in the superconducting wire is not uniform or there are defects on the surface, it is easy to break during the subsequent stretching process of the wire, which seriously affects the preparation process of NbTi and Nb3Sn superconducting wire, thus restricting the development of energy manufacturing equipment.
