MELTING DIFFUSION WELDING METHOD FOR SECOND GENERATION HIGH TEMPERATURE SUPERCONDUCTING WIRE

摘要

The present invention relates to a welding method for a second generation high temperature superconducting wire including a substrate, a buffer layer, a superconductor layer, and a stabilizing material layer, wherein parts of the stabilizing material layers contained in two strands of the second generation high temperature superconducting wire are removed, the superconductor layers of two strands of the second generation high temperature superconducting wire exposed by the removal of the stabilizing material layer abut each other and are heated to the melting point of the superconductor layer to melt-diffuse the abutting superconductor layers and weld two strands of the second generation high temperature superconducting wire together. Subsequently, the welded portion is oxygenation-annealed under an oxygen atmosphere to recover superconducting properties of the second high temperature superconducting wire. The above-described configuration of the present invention enables superconductor layers to directly abut each other and to be melt-diffused without using a mediator, thus producing a wire having a full length with a rare junction resistance as compared to a normal conduction junction method. Specifically, the present invention brings a partial oxygen pressure to a nearly vacuum state to lower the melting point, thereby enabling junction processes to be performed without melting a stabilizing material layer containing silver (Ag).