Superconducting members and methods of manufacturing thereof

Claim 1

A method of manufacturing a superconducting member embodying a superconductor of A15 crystal structure having the general formula A 3 B, where A comprises niobium or vanadium metal and B is one or more elements which when reacted with the metal A will form the said superconductor, which method comprises forming a composite material essentially consisting of a carrier material and one or more of the elements B, providing a plurality of discrete rods of a base material essentially consisting of the metal A within and in contact with the composite material, forming the composite material with the rods of base material therein and a metal, which is eventually to provide stabilisation, into a unitary structure in which a barrier layer of a metal A impermeable to the B element or elements is located as a diffusion barrier separating the stabilising metal from the composite material along the whole length of the unitary structure, and an additional barrier layer between the said barrier layer of metal A and the composite material, which additional barrier layer during subsequent heat treatment inhibits formation of superconducting A 3 B compound over the whole or a substantial part of the surface of the diffusion barrier layer of metal A which, but for the additional barrier layer could be in contact with the composite material, reducing the unitary structure to wire form by a mechanical reduction process whereby the rods of base material become filaments in a matrix of composite material and the stabilising metal together with the barrier layer extend along the length of the wire, and heat treating the wire to cause reaction between the said filaments of base material and the B element or elements to form filaments of superconducting A 3 B compound, whilst said additional barrier layer inhibits formation of superconducting A 3 B compound over the whole or a substantial part of the said surface of the diffusion barrier layer, said carrier material comprising an element selected from the group consisting of copper, silver and gold, which element under said heat treatment neither reacts substantially with the base material nor undesirably influences reaction between the chosen B element or elements and the base material.

Claim 2

A method of manufacturing a superconducting member embodying a superconductor of A15 crystal structure having the general formula A 3 B, where A comprises niobium or vanadium metal and B is one or more elements which when reacted with the metal A will form the said superconductor, which method comprises forming a composite material essentially consisting of a carrier material and one or more of the elements B, providing a plurality of discrete rods of a base material essentially consisting of the metal A within and in contact with the composite material, forming the composite material with the rods of base material therein and a metal, which is eventually to provide stabilisation, into a unitary structure in which a barrier layer of a metal A impermeable to the B element or elements is located as a diffusion barrier separating the stabilising metal from the composite material along the whole length of the unitary structure, and an additional barrier layer between the said barrier layer of metal A and the composite material, which additional barrier layer during subsequent heat treatment inhibits formation of superconducting A 3 B compound over the whole or a substantial part of the surface of the diffusion barrier layer of metal A which, but for the additional barrier layer could be in contact with the composite material, reducing the unitary structure to wire form by a mechanical reduction process whereby the rods of base material become filaments in a matrix of composite material and the stabilising metal together with the barrier layer extend along the length of the wire, and heat treating the wire to cause reaction between the said filaments of base material and the B element or elements to form filaments of superconducting A 3 B compound, whilst said additional barrier layer inhibits formation of superconducting A 3 B compound over the whole or a substantial part of the said surface of the diffusion barrier layer, said carrier material comprising an element selected from the group consisting of copper, silver and gold, which element under said heat treatment neither reacts substantially with the base material nor undesirably influences reaction between the chosen B element or elements and the base material.