US 6,440,904 B1 · High-temperature superconductor arrangement

Abstract

Ceramic high-temperature superconductors (1) which are intended to be used as current limiters in alternating-current lines should have a bypass layer (2) whose electrical resistivity is increased by more than 10 times with respect to that of a pure noble-metal bypass layer. In order to achieve this, the noble-metal bypass layer (2) of the high-temperature superconductor (1), preferably of silver, is alloyed with a base metal, preferably Pb or Bi or Ga, by a thermal treatment. The ratio of the bypass layer thickness (d2) of the noble-metal bypass layer (2) to the superconductor layer thickness (d1) is adjusted to <1/5. A base-metal bypass layer (3) of steel whose electrical resistivity is in the range between 10 μΩ×cm and 100 μΩ×cm at 77 K is soldered on or applied under isostatic pressure over the noble-metal-containing bypass layer (2). The noble-metal bypass layer thickness d2 and the base-metal bypass layer thickness d3 are to be chosen so that the ratio ρ2/d2 is >0.5×ρ3/d3, where ρ2 and ρ3 are the electrical resistivity of the noble-metal-containing bypass layer (2) and the base-metal bypass layer (3, 3′), respectively.

Claims17

Dependent claims

A high-temperature superconductor arrangement

a) comprising a layered ceramic high-temperature superconductor;
b) which is in thermally and electrically conducting contact via at least one of its two principle surfaces with at least one electrical base-metal bypass layer;
c) a noble-metal-containing bypass layer being disposed between the high-temperature superconductor and the at least one base-metal bypass layer;
d) wherein the electrical resistivity (ρ3) of said at least one base-metal bypass layer is in the range between 10 μΩ·cm and 100 μΩcm at 77 K;
e) wherein the ratio of the noble-metal bypass layer thickness (d2) to the superconductor layer thickness (d1) is 1/5;
f) wherein the superconductor layer thickness (d1) is in the 0.5 μm-2 mm range;
and
g) wherein 1 j c · d1 · 1 50 ⁢ ⁢ V cm ≤ ρ ⁢ ⁢ 3 d ⁢ 3 ≤ 1 j c 2 · d1 2 · 50 ⁢ ⁢ W cm 2 ,
where d1 is thickness in cm of the high-temperature superconductor, ρ3 is electrical resistivity in Ω·cm of the base-metal bypass layer, d3 is thickness in cm of the base-metal bypass layer thickness, and jc is critical current density in A/cm2 of the high-temperature superconductor.

6 more elements

Dependencies are inferred from the claim text.

High-temperature superconductor arrangement

Life of this patent

High-temperature superconductor arrangement

Life of this patent

Abstract

Claims17