Direct production of Nb3Al superconducting coil by electron beam irradiation on a cold-sprayed cylinder

The direct production of Nb3Al superconducting coils using the combinational technology of ‘cold spray’ as physical deposition and ‘electron beam’ as surface modification has been proposed. Using this method, the helical line of the Nb3Al superconductor is produced directly on a cylinder without conventional wiring process. In order to prove the possibility of direct coil production, we first made flat-plate and cylindrical samples, and then examined the characteristics as superconductor. The flat-plate samples showed the phase transition in magnetization and the characteristics of superconductivity when the output powers of the electron beam were over 800 W at a beam speed of 3 m/s and 1200 W for 6 m/s. It was confirmed that a 10-turn single-layer coil with a ϕ40 mm diameter and a length of 50 mm generated a magnetic field of 2.7 mT at 20.5 A.