NbTi/YBCO (yttrium barium copper oxide) composite superconducting wire with circular section

Abstract

The invention discloses an NbTi / YBCO (yttrium barium copper oxide) composite superconducting wire with circular section, belonging to the field of superconducting materials. The composite superconducting wire is characterized in that a low temperature superconducting wire with circular section is covered by a stable layer; the stable layer is covered by a high temperature superconducting substrate layer through rolling; Ag solders are used for soldering the high temperature superconducting substrate layer in the rolled gaps of the high temperature superconducting substrate layer and forming an Ag soldered joint; a high temperature superconductor coating is coated on the outer surface of the high temperature superconducting substrate layer; the low temperature superconducting wire and the stable layer are NbTi / Cu low temperature composite superconducting wires; and the high temperature superconducting substrate layer and the high temperature superconductor coating are respectively madeof Ni-W alloy tapes and high temperature superconducting material YBCO. The composite superconducting wire has the following beneficial effects: a YBCO high temperature superconducting coating conductor and the NbTi / Cu low temperature composite superconducting wires are combined; by utilizing the characteristic that the n value of the YBCO high temperature superconducting material is much less than the n value of the low temperature superconducting material NbTi and the characteristic of high superconductor critical temperature, rise of the whole voltage of the low / high temperature composite superconducting wires can be suppressed and temperature rise of the composite superconducting wire can be reduced; and compared with the traditional low / high temperature superconducting magnets, the superconducting magnet operates more stably, has higher efficiency and is safer, and is applied to high-field MRI (magnetic resonance imaging) magnets, MRI magnets and the like.

Description

technical field

[0001] The invention belongs to the field of superconducting materials, in particular to a circular section NbTi / YBCO composite superconducting wire. Background technique

[0002] One of the most important properties of a superconductor is that when the temperature drops below the critical temperature T c and the critical magnetic field B c And below, the resistance will suddenly disappear. at the critical temperature T c Below, there is a critical current I c ; When the current passing through the superconductor is greater than the critical current I c , the superconductor will switch to a normal state, that is, a resistive state. In addition, the critical current I c It is a function of temperature T and magnetic field B; with the increase of temperature T or magnetic field B, the critical current I c will become smaller until it disappears and becomes normal. At a certain temperature T, there exists a critical magnetic field B c , when the magneti...

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