| 摘要 |
PURPOSE:To apply uniform pressure with ease to a wire material wound into a coil shape where mechanical pressurization is difficult by applying mechanical pressure to a superconducting wire material utilizing the property of a shape- memory alloy which is restored to a shape before its deformation upon heating. CONSTITUTION:A ring-shaped member 3 having a smaller internal shape than a coil shape is formed from a shape memory alloy and expanded in its diameter under lower temperature into a shape where it can fit to the outside of a superconducting coil 2. Once after the ring-shaped member 3 is fitted to the superconducting coil 2 the ring-shaped member 3 is heated to a temperature higher than the marten site transformation point of the shape memory alloy of the ring-shaped member, the ring-shaped member 3 is liable to be reduced in its diameter into a shape before the deformation to tighten the superconducting coil. Hereby, a wire material can easily undergo pressurization processing after the coil has been wound to improve the critical current density of the wire material. |
