PURPOSE: To obtain a Nb3Sn superconductive wire rod having a high current density capable of supplying sufficient Sn to the interior thereof by gradually increasing the Nb concentration distribution of a wire rod from a Sn diffusion source side toward a diffusion terminal side.
CONSTITUTION: The Nb concentration of a sintered body layer 4 assembled in a billet 1 is gradually increased in monotony from a Sn diffusion source side toward a diffusion terminal side. Accordingly, in thermally diffusing Sn from the surface side or the inside of a wire rod made of the billet 1, interruption of Sn diffusion due to Nb3Sn generated inside the wire rod is restrained so that Sn can be sufficiently supplied to a portion of the sintered body layer 4 distant from the diffusion source. Consequently, a satisfactory reaction of Nb with Sn can be conducted over the whole sintered body layer 4, thereby obtaining a Nb3Sn superconductive wire rod having a sufficient high critical current density.
SHIMADA MASAO
MIZOMATA YOUICHI
