Wrapped tantalum diffusion barrier
AssigneeAirco, Inc.
InventorsMorris S. Young, David C. Larbalestier
Life of this patent
Estimating the term…
Abstract
A multifilamentary stabilized superconductor of the A-15 type is disclosed wherein the A-15 compound is formed on rods of niobium or vanadium by diffusion of tin or gallium, respectively, from a copper alloy matrix and wherein stabilization is provided by an external layer of copper. The stabilizing copper is protected from tin or gallium diffusion by a number of spirally wrapped layers of tantalum separated from one another by copper layers.
Claims3
A stabilized multifilamentary superconductor wherein the superconductive material is of the type A.sub.3 B, is selected from the group consisting of Nb.sub.3 Sn and V.sub.3 Ga, and is formed by diffusion of the B mateial from a matrix of an alloy of Cu and the B material onto the surfaces of wires or filaments of the A material embedded therein, and wherein the improvement comprises providing a quantity of a stabilizing metal on the external surface of the conductor selected from the group consisting of Ag, Au, Al and Cu and isolating this stabilizing metal from diffusion of the B material by providing a wrapped diffusion barrier consisting of at least one essentially complete layer, having substantial layer overflap, of a refractory metal foil impermeable to tin between the central matrix and the stabilizing metal, the overlapping portions of said layer being separated from one another by an interleaved foil of a metal softer than the refractory metal.
A stabilized multifilamentary superconductor, comprising:
- a central matrix consisting essentially of a plurality of Nb rods in a Cu/Sn matrix, Nb.sub.3 Sn having been formed at the interface of the matrix and the Nb rods;
- a quantity of stabilizing Cu on the external surface of the conductor;
- and
- a barrier interposed between the matrix and the stabilizing Cu, the barrier comprising at least two nominally complete layers of a refractory metal foil, said layers having been formed by wrapping a continuous length of said foil around the matrix, and said layers being separated from one another by interleaved Cu foil.
Dependencies are inferred from the claim text.