JPS62106607A - Compound superconductive coil - Google Patents

Abstract

PURPOSE:To display an insulating effect even after a diffusion heat treatment is performed as well as to improve the strength of a superconductive coil by a method wherein the insulating layer, which will be formed outside a compound superconductive base line, is formed into a double-layer structure consisting of the heat-resisting layer of crystallized non-alkali vitreous material and an insulating coating. CONSTITUTION:A compound superconductive coil is formed by applying an insulating layer on the outside. At that time, the insulating layer is formed into a double structure consisting of the insulating layer 2 of crystallized non- alkali vitreous material and an insulation-coated layer 3. As a result, the insulating layer 2 can withstand the heat treatment performed after a diffusion heat treatment, the prescribed insulation effect is displayed, and the insulating layer 2 is protected by the coated layer 3 when a coil processing is performed, thereby increasing the strength of superconductive coil.

Description

DETAILED DESCRIPTION OF THE INVENTION 1-Field of Industrial Application Σ The present invention relates to a superconducting coil having an insulating layer having excellent insulating properties and mechanical properties.

"Conventional technology" In superconducting magnets used at extremely low temperatures,
In the configuration B in which compound-based superconducting coils are used, the following types of insulating layers are conventionally known as insulating layers used for insulating between each coil.

(1) A formal insulating layer formed by baking Polmar resin.

(2) A polyresin insulating layer formed by wrapping polyimide or polyimide amide tape.

(3) Improve flexibility A glass insulating layer is formed by wrapping a glass tape formed by mixing a binder component, or by bag-clamping a glass yarn formed by mixing a binder component.

(4) Wrap a mica tape composed of a binder component into the mica insulating layer.

"To the problem to be solved by the invention" By the way, in the compound-based superconducting wire constituting the compound-based superconducting coil, the compound superconductor is extremely hard;
Because of the brittleness L), there is a risk of deterioration or destruction due to bending stress associated with coil processing. Therefore, conventionally,
Superconducting coils are manufactured by applying coil processing to wire rods that are highly workable in a complex state in which the components that make up superconducting compounds exist separately, and then applying diffusion heat treatment to this wire rod after coil processing to generate superconducting compounds. Was.

Therefore, conventionally, the insulation treatment performed using the insulation method is applied to the wire rod in the composite state, and a compound-based superconducting coil is manufactured by sequentially applying coil processing and diffusion heat treatment for compound generation to the insulated wire rod. It will be done.

However, since the diffusion heat treatment is a process of heating at a temperature of 600 to 800°C for 20 to 200 hours,
This diffusion heat treatment has caused problems in each of the insulating materials as described below.

First, among the above-mentioned insulating layers, the formal insulating layer and the polyresin insulating layer are significantly deteriorated by the heating of the above-mentioned diffusion heat treatment, resulting in a problem that the insulating properties are impaired. In addition, although the glass insulating layer and the mica insulating layer can withstand the heat of the diffusion heat treatment, the binder component (often starch-based substances) mixed in for the purpose of improving flexibility is carbonized by the heating, resulting in insulation. This had the problem of greatly deteriorating the performance. In addition, if a superconducting coil is manufactured using Form 1 without containing the binder component, or using a glass insulating layer or a mica running edge layer, the winding of the super'1a conductor wire will be carried out at the corner of the superconducting wire at the corner of the insulating layer. In addition, friction between superconducting wires during coil processing may cause cracks, fraying, or thin areas in the insulating layer due to wear and tear, resulting in problems with practical insulation properties.

``Object of the Invention'' The present invention has been made in view of the above-mentioned problems. The object of the present invention is to provide a compound-based superconducting coil having the following properties.

"Means for Solving the Problems" In order to solve the above problems, the present invention provides a compound-based superconducting coil coated with an insulating layer on the outside, the insulating layer being made of crystallized non-alkali glass. It has a multi-layer structure of an insulating layer and an insulating coating layer.1 Function: The heat-resistant insulating layer made of crystallized alkali-free glass withstands the heat treatment associated with diffusion heat treatment and exhibits the desired insulating effect. The upper layer of insulation protects the lower layer of insulation during processing.

1 Embodiment Σ Figure 1 shows the cross-sectional structure of a superconducting coil A according to an embodiment of the present invention. It is composed of a base-side heat-resistant insulating layer 2 made of a non-acrylic insulating material and an insulating coating layer 3 covering the outside of the heat-resistant insulating layer 2.

The compound-based superconducting baseline 1 is manufactured by subjecting a superconducting wire containing a combination of metal elements (for example, Nb and Sn) necessary for producing a superconducting intermetallic compound (for example, Nb5Sn) to a diffusion heat treatment described below. Therefore, it has a superconducting intermetallic compound inside. This superconducting baseline 1
is highly ductile and has excellent workability in its strand state before diffusion heat treatment.

The heat-resistant insulating layer 2 is made of an acrylic-free insulating material such as non-crystallized enamel, and is coated on the superconducting wire 1 by the method described below.

The insulating coating layer 3 is composed of a quartz tape 11 that does not contain the binder component described above.

M in FIG. 2 indicates a superconducting mucknet constructed by winding the superconducting coil A around a wire bobbin 5.

A method of manufacturing the superconducting coil 8 and superconducting magnet M will be described below.

FIG. 3 shows the manufacturing state of the superconducting magnet M. In the figure, 6 indicates a wire reel around which the superconducting wire 7 is wound, and 8 in the figure indicates an immersion device equipped with a glass frit bath, etc. In the figure, IO indicates a tape reel wound with quartz tape +1 that does not contain a binder component.

In order to manufacture a superconducting macnet M using the super 71j conductive strand 7, first, the superconducting strand 7 pulled out from the strand reel 6 is supplied to the dipping device 8.

The dipping device 8 is equipped with a cleaning device, a finger removal device, a pretreatment device such as a base plating device, and an alkali-free crystalline vitreous enamel glass frit bath. By passing through, the dipping device 8 coats the outer periphery of the superconducting wire 7 with a glass frit layer of enamel (e.g., an enamel composition having a thickness of about 0.1 to 0.2 mm and consisting of components such as MgO1Bao and B203.5ift). layer) +2.

Next, the quartz tape II drawn out from the tape reel 10 is wound around the superconducting strand 7 that has passed through the dipping device 8 to form an insulating coating layer 3, and then the superconducting wire 7 is wound around the winding bobbin 5. Here, the superconducting strand 7 contains elements constituting a compound superconductor in a complex state and is highly workable, so that the winding operation can be carried out easily. Note that during the winding operation, the insulating coating layers 3 on the outer periphery of the superconducting wire 7 rub against each other, but if these insulating coating layers 3 rub against each other and are worn out, the glass frit layer 12 inside may be damaged or damaged. Insulating coating layer 3 is glass tape 1-1i
'7i12 has a protective effect. During the winding, there is a risk that the glass frit layer 12 may peel off in the portion where there is a large amount of bending m, but the quartz tape 11 prevents this separation. Moreover, this glass frit layer 12 is O11~0.2m
Since it is thin, the space factor with respect to the superconducting base line I can be made comparable to that of a conventional insulating layer.

After this, the winding bobbin 5 is heated to the crystallization glass firing temperature (800 to 8508 C) of the glass frit layer I2 to turn the glass frit layer 12 into the heat-resistant insulating layer 2.
A superconducting intermetallic compound is generated inside the superconducting wire 7 by diffusion heat treatment (heating treatment at 600 to 800° C. for 20 to 200 hours), and the superconducting magnet M is configured by using the superconducting wire 7 as a superconducting base line l. do.

In the superconducting magnet M, since the heat-resistant insulating layer 2 is formed from an alkali-free crystallized glass insulating material,
It can withstand diffusion heat treatment and exhibits high insulation even after the diffusion heat treatment, and since the insulating coating layer 3 does not contain a binder component, it does not generate carbide of the binder component. In addition, since the heat-resistant insulating layer 2 formed by crystallization has high mechanical strength, when the superconducting magnet M is energized to generate a strong electromagnetic force, an external force acting on the superconducting coil A due to this electromagnetic force is generated. It has a highly reliable configuration and is designed to withstand high temperatures.

In the superconducting magnet M mentioned above, the amorphous material softens at about 650°C, while the amorphous material softens at about 800 to 850°C.
Since the alkali-free crystallized glass material of C, which is highly stable even at high temperatures, has a heat-resistant insulating layer 2 made of wax, it can sufficiently withstand high temperatures during diffusion heat treatment and exhibit a predetermined insulating effect.

In the embodiment described above, the outer surface of the superconducting wire 7 may be covered with the quartz tape 11, and the glass frit layer I2 may be formed thereon. Furthermore, in order to form the glass frit layer 12 on the outside of the superconducting coil 7, in addition to the above-mentioned dipping method,
Methods such as electrostatic coating method, depth forming method, or electrophoretic electrodeposition method may also be used.

Further, the insulating layer formed outside the superconducting base line l may have a multilayer structure of two or more layers, and the insulating coating layer 3 may be a quartz tape! ! It may be constructed from other glass insulating materials or mica insulating materials. Furthermore, the firing treatment for crystallization performed when forming the superconducting magnet M can be performed using the heat treatment during the diffusion heat treatment.

"Manufacturing example" Rectangular cross section (cross section dimensions: 1.5mm x 3゜Omm)
A solenoid coil was manufactured using the Nb3Sn-based ultrafine superconducting wire. A glass frit layer with a thickness of 0.15 mm is applied to the outer circumference of this solenoid coil by passing it through a glass frit bath, and when this glass frit layer is in a semi-dry state, a S of 0.25 mm in thickness and 15 mm in width is applied to the outer circumference of the solenoid coil. −
Insulation treatment was performed by half wrapping the glass tape. This insulated superconducting cable is made of stainless steel (S
It is wound on a winding bobbin made of US30.4) with an outer diameter of 15 mm.
A magnet with a diameter of 0 mm and a height of 150 mm was produced. Due to friction caused by contact between superconducting wires,
Although the quartz glass tape was slightly fluffed, no major damage was caused. After this, the Macnet was heated to 750°C for 50 hours, and the glass frit layer was subjected to firing treatment and diffusion heat treatment at the same time, thereby making the glass frit layer a heat-resistant insulating layer and adding Nb+Sn to the inside of the superconducting wire. A superconducting compound is produced to form a superconducting magnet. The line-to-line insulation resistance of this superconducting magnet showed an infinite value before the diffusion heat treatment, and an infinite value after the diffusion heat treatment. Therefore, the heat-resistant insulating layer has sufficient insulation properties. In addition, the superconducting magnet exhibited sufficiently high superconducting properties as designed in an energization experiment.

By the way, when a superconducting magnet is manufactured without using the above-mentioned glass slit layer, the insulation resistance between the wires was several hundred ohms when the superconducting baseline was processed into a five-layer coil, but after diffusion heat treatment, it became several tens of ohms. Ω, and deterioration progressed.

"Effects of the Invention" As explained above, the present invention provides compound-based superconductivity, 11 (
Form an insulating layer on the outside of the wire.Crystallize the insulating layer at 511℃. When diffusion heat treatment is performed, the heat-resistant insulating layer can withstand this heat treatment, so that the heat-resistant insulating layer can exhibit a predetermined insulating effect after the diffusion heat treatment.Furthermore, the heat-resistant insulating layer made of crystallized glass After crystallization, the mechanical strength is high, so this heat-resistant insulating layer exerts a strong effect on the superconducting coil, increasing the strength of the superconducting coil. When force is applied,
It has a highly reliable structure that can withstand this electromagnetic force.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a superconducting wire according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a superconducting magnet constructed using the superconducting wire shown in FIG. 1, and FIG. FIG. 2 is a perspective view showing a method of manufacturing the superconducting magnet shown in FIG.

Claims (1)

[Claims] 1. A compound superconducting coil externally coated with an insulating layer, wherein the insulating layer has a multilayer structure of a heat-resistant insulating layer made of crystallized alkali-free glass and an insulating coating layer.