JPH01119002A - Superconductor coil and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain stable superconductive characteristics by thermally treating wound superconductive wires in the metallic tube of which an oxide superconductive powder is filled, and filling and fixing a gap between the inner wall of the tube and the oxide superconductor as well as between such wound superconductive wires by a resin. CONSTITUTION:Wires are made by filling a powder of an oxide superconductor 3 in a metallic tube 2, superconductive wires 1, in the formed throughhole 4 of which an epoxy resin is filled, are wound along a winding frame while coating the peripheral thereof with an alumina fiber sleeve 6. This wound body is placed in a baking furnace, increasing its temperature up to 930 deg.C. The epoxy resin 5 in the throughhole 4 is volatilized, the volume of the oxide superconductor being reduced due to a two-hour baking, a gap 8 being formed inside the superconductive wires 1, whose temperature being increased to 600 deg.C and maintained for 1hour, and slowly cooled to 370 deg.C. Then the wound body is placed in a vacuum container, an epoxy resin 9 is impregnated into the gap 8 and the throughhole 4 and between superconductive wires 1, such epoxy resin 9 being fixed by heating, and finally a superconductive coil is obtain by integrating the entire wound body with the insulating sleeve 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a superconductor coil using an oxide superconductor and a Va method thereof.

(Prior Art) In recent years, it has been announced that layered perovskite-type oxides based on Ba-La-Cu-0 have a high critical temperature, and since then, research on oxide superconductors has been carried out in various places. (Z, Phys, B Condensed Mat
ter64, 189-193 (1986)). Among them, defective perovskite type ((LnBa Cu O type) with oxygen defects represented by Y-Ba-Cu-0 system)
(δ represents oxygen defect 237-δ is usually less than 1, Ln is Y 1La, Sc, Nd15
m, Eu, Gd.

At least one element selected from Dy, HOlEr, Tm, YbJ3 and Lu, -9 part of 8a can be replaced with Sr, etc.) The oxide superconductor has a critical temperature of 90 or higher and a boiling point of liquid nitrogen. It is attracting attention as a very promising material because it exhibits high temperatures (Phys, Rev,
Lett.

Vol. 58 No. 9, 908-910).

Incidentally, such oxide superconductors are obtained as sintered bodies of crystalline oxides or their powders, so when using them, for example, as superconductor coils, first, a metal tube is filled with oxide superconductor powder. After that, it is drawn into a long wire rod, and then this super T is wrapped in a suitable winding frame.
Attempts have been made to use the II body wire as a coil by winding it.

By the way, the superconducting properties of this oxide superconductor deteriorate due to strain etc. that occur during winding. It is said that it is appropriate to perform heat treatment to improve superconducting properties by supplying oxygen inside the material.

(Problems to be Solved by the Invention) However, in the method for manufacturing a superconductor coil described above, the volume of the oxide superconductor in the metal tube decreases due to sintering of the oxide superconductor powder in the heat treatment step. There is a problem in that there is a very high possibility that a gap will be formed between the metal tube and the oxide superconductor. In this way, when a void occurs in the superconductor wire, the machine lining 1q decreases, and the presence of this void allows the oxide superconductor to move within the metal tube due to electromagnetic force, which reduces the flow of current. Problems may arise, such as instability or even failure to cause quenching due to the movement of the oxide superconductor.

Such a problem also occurs due to the movement of the superconductor wire itself in the wound body.

In addition, as mentioned above, when heat treatment is applied to a metal tube that has been wound into a desired shape, even if silver is used, which has an excellent ability to supply oxygen, the oxide superconductivity that exists inside the wound tube can be removed. In the body, there was also a problem of insufficient supply of oxygen, resulting in non-uniform superconducting properties as a whole.

The present invention was made in order to solve these conventional problems, and eliminates the existence of a gap between the metal bending tube and the oxide superconductor, and makes it possible to use it as a 1ri conductor wire material mechanically. The object of the present invention is to provide a superconductor coil that can stably exhibit its excellent characteristics by improving the strength and the rigidity of the coil as a whole, and a method for manufacturing the same.

[Structure of the Invention] (Means for Solving the Problems) The superconductor coil of the present invention is a superconductor coil formed by heat-treating a wound body of a superconductor wire in which a metal tube is filled with oxide superconductor powder. The gap between the metal tube inner wall of the superconductor wire and the oxide superconductor and the super-f of the wound body
It is characterized in that the space between the fi conductor wires is filled and solidified with resin.

Further, the method for manufacturing a superconductor coil of the present invention includes gold flu! filled with oxide superconductor powder! A process of processing the linear body into a linear body, forming a plurality of through holes reaching the internal filling from the surface of the metal tube of the linear body obtained by this process, and after closing these through holes with an organic substance, winding it into a coil shape. a step of heat-treating the wound body to volatilize the organic matter and supplying oxygen from the through-hole and the surface of the metal tube; The method is characterized by a step of filling the superconductor coil with a thermosetting resin and solidifying it.

Although a large number of oxide superconductors are known, the use of perovskite-type oxide superconductors containing rare earth elements, which have a high critical temperature, have a high practical effect. The oxide superconductor containing a rare earth element and having a perovskite structure may be any material as long as it can realize a superconducting state, for example, LnBa Cu O system (δ represents an oxygen defect and is usually a number of 123 γ-δ or less). , Ln is Y, La, Sc, Nd%Sm
, Eu, Gd.

oy, +10, at least one element selected from ErlTm5Yb and Lu, a part of Ba can be replaced with Cal), etc.! ! Examples include oxides having a perovskite type in a broad sense, such as a defective perovskite type having I elementary defects and a layered perovskite type such as a 5r-La-Cu-0 system.

In addition, rare earth elements are defined in a broad sense, and S(Y and [a
It shall include the system. A typical system is Y-Ba-Cu
In addition to -0 series, Y is Eu, DL llo, Er,
Tm, Yb.

Examples include systems in which rare earth elements such as Lu are substituted, 5c-Ba-Cu-0 systems, 5r-La-Cu-0 systems, and systems in which Sr is substituted with Ba1Ca.

The oxide superconductor powder used in the present invention is produced, for example, as follows.

First, the constituent elements of the perovskite oxide superconductor, such as v, Ba, and CI, are sufficiently mixed. When mixing,
In addition to oxides and carbonates such as Y2O3, BaCO3, and CuO that can be used as raw materials, compounds such as nitrates and hydroxides that are converted into oxides after firing may also be used. Furthermore, oxalate obtained by a coprecipitation method or the like may be used. The elements constituting the perovskite-type oxide superconductor are basically mixed so as to have a stoichiometric composition, but there may be a slight deviation depending on the manufacturing conditions, etc. for example,
In the Y-Ba-CO-0 system, Ba for V 1 mol
The standard composition is 2 mol, Cu 3 mol, but in practice, Ba 2 ± 0.6 m for Y 1 nof.
ol, C03±0.2 mol deviation is not a problem.

After thoroughly mixing the above-mentioned raw materials, 850 to 98
Fire at a temperature of about 0°C. Next, if necessary, heat treatment is performed in an oxygen-containing atmosphere, preferably an oxygen atmosphere, or by slow cooling to about 300°C in a similar atmosphere, oxygen is injected into the oxygen defects δ and the superconducting properties are improved. You can do it.

This heat treatment is usually carried out at about 300°C to 700°C.

Next, this fired product is pulverized using a ball mill, a sindo grinder, or other known means. At this time, the perovskite-type oxide superconductor is split from the cleavage plane and becomes fine powder. This pulverization is preferably performed so that the average particle size is 0.1 to 5 μm.

The oxide superconductor powder prepared in this manner (9) has an oxygen-deficient perovskite 1 structure (Ln
BaCuO (δ is usually a number of 1 or less)) 237-
becomes δ. In addition, it is also possible to replace Ba with Sr, Ca, etc., and roughly replace the - part of Cu with Ti, V SCr,
Hn, "e, C01Ni, addition, etc. can be substituted. This substitution number can be set as appropriate within a range that does not reduce the superconducting properties, but too much substitution may reduce the superconducting properties. 80mo 1% or less.

To explain in more detail the method for manufacturing a superconductor coil of the present invention, first, the oxide superconductor powder produced by the method described above is filled into a tube made of a normal conductive metal.

Examples of the material for this tube material include silver, copper, stainless steel, etc. Silver is particularly preferably used because it does not oxidize even at high temperatures and has excellent oxygen supply ability and shape maintaining ability. Next, after compacting the powder from outside the tube using a swaging machine or the like, the tube is made into a long length by wire drawing or the like and processed into a linear shape.

Next, a plurality of through holes are formed from the surface of the metal tube filled with the oxide superconductor powder to the internal filling. This d through hole can be easily formed by drilling or laser machining. This d through hole becomes a Wli cable supply hole during heat treatment and a resin supply hole during solidification with resin, which will be described later. If the size of this through hole is too large, it will be inconvenient during winding, which will be described later.On the other hand, if it is too small, the amount of oxygen and resin supplied will be insufficient.
．． Approximately 5 mm is appropriate. In addition, the oxide superelectric 3
In order to supply oxygen to the 17 bodies, it is preferable to provide them at equal intervals.

Next, the Li through holes in this linear body are blocked with an organic material such as a glue composition, rubber, or resin, and the oxide superconductor powder is placed on a suitable winding frame, for example, in order to prevent the oxide superconductor powder from being lost during winding. The linear body is wound to form a coil of the desired shape. Further, the insulation LJ between the superconductor wires in the wound body can be achieved, for example, by covering the superconductor wire with a sleeve made of an insulating material such as alumina fiber before winding.

Next, this wound body is subjected to heat treatment to improve its superconducting properties. In this heat treatment, first, the organic matter filled in the d through hole is volatilized in a temperature raising process, etc.
The oxide superconductor powder is sintered at a temperature of about 100 mL for about 1 to 50 hours. Then, from this heat treatment temperature,
Preferably, the temperature is lowered to about 600°C, and then 3OO0
Superconducting properties are improved by slowly cooling the material to about 0.degree. C. while supplying sufficient oxygen. Supplying oxygen from about 600° C. is effective because the crystal phase becomes orthorhombic, increasing the oxygen absorption efficiency. It is also effective to maintain the temperature at about 300°C to 700°C for several hours while supplying sufficient oxygen.

In addition, as for the method of supplying oxygen in this heat treatment step, when supplying oxygen, the inside of the firing furnace is kept in a reduced pressure state with a culm of -H10tOrr or less, preferably in a vacuum state (1 x 1O-1torr).
By supplying oxygen gas to a normal pressure state, it is possible to supply oxygen to the entire wound body, which is preferable. J3, at this time, the volume of the oxide superconductor powder decreases because it is sintered at the above-mentioned heat treatment temperature, and as a result, a void is created between the inner wall of the metal tube and the oxide superconductor. There is. Oxygen is uniformly supplied by the voids and the through holes. By performing heat treatment in this manner, the amount of oxygen introduced into the oxygen vacancies δ of the oxide superconductor increases, resulting in an oxide superconductor with fewer oxygen vacancies, resulting in an oxide superconductor with deteriorated superconducting properties. .

After this, a thermosetting resin is filled between the gap d3 formed in the superconductor wire of the wound body cooled to room temperature and between the superconductor wires and solidified, thereby preventing the movement of the oxide superconductor within the superconductor wire. At the same time, the rigidity of the superconductor coil body is increased.

This resin can be filled evenly into the voids inside the superconductor wire by using negative pressure, for example.

(Function) In the superconducting coil of the present invention, the voids created when the oxide superconductor powder in the superconducting wire is sintered are filled with a resin and solidified, and the superconducting coil is solidified. It is also integrated with resin, so it has strong mechanical strength.
Further, it is possible to prevent movement of the oxide superconductor within the superconductor wire and movement of the superconductor wire due to electromagnetic force, etc., and it is possible to stably obtain the characteristics of the superconductor coil. Furthermore, since the entire superconductor coil is sealed with resin in this way, it is possible to completely prevent moisture from entering, and it is possible to stably obtain the characteristics for a long period of time.

Furthermore, in the manufacturing process, oxygen can be sufficiently supplied during heat treatment through the through holes for resin supply, so that the properties of the superconductor wire are also very excellent.

(Example) Next, examples of the present invention will be described.

Example particle size 1-5 μm BaC0, powder 2m01%, Y2O3
Powder 0.5m01% and CuO powder 3mo1% were sufficiently mixed together and fired at 900°C in the atmosphere for 48 hours to react, and then this fired product was further fired at 800°C in an oxygen atmosphere for 24 hours to react. After introducing oxygen into the oxygen vacancies, the powder was pulverized using a ball mill to obtain perovskite-type oxide superconductor powder with an average particle size of 0.5 μm.

Next, one end of this oxide superconductor powder with an outer diameter of 20 mm + inner diameter of 16 n + n + x and a length of 70 mm was placed in a silver flute sealed with a silver material, and after being pressed with a press pressure of 1 ton/cd, the other end was The tube was plugged and welded leaving a ventilation hole, and one end was then held in a Turk's head machine and cold wire drawn to an outer diameter of 2.0 mm to form a wire.

Next, 5111 is drilled in the radial direction of this linear body.
Through holes with a diameter of 0.2 mm were formed at m intervals, and the through holes were filled with epoxy resin.

Next, as shown in FIG. 1, this metal tube 2 is filled with powder of oxide superconductor 3 to form a wire, and the superconductor wire 1 filled with epoxy resin is inserted into the formed C1 through hole 4. The outer periphery is covered with a sleeve 6 made of alumina fiber, and the dimensions of the same part are 3OO mm in diameter x 200 mm in width.
Wound in layers.

Then, as shown in FIG. 2, the wound body of superconductor wire produced in this manner (FIG. 2-a) was placed in a firing furnace and heat-treated. In addition, 5 in the figure is an epoxy resin filled in the n-hole 4. In the heat treatment, the temperature is first raised to 9300°C. During this temperature rising process, the epoxy resin 5 in the through hole 4 is volatilized (FIG. 1-b). This temperature was then held for 2 hours to sinter the oxide superconductor powder.

By sintering the powder of the oxide superconductor 3, the volume of the oxide superconductor is reduced, and voids 8 are formed in the superconductor wire 1 (FIG. 1-C). Next, the temperature was lowered to 600°C at a rate of 5°C/min, held at 600°C for 1 hour, and then slowly cooled to 370°C at a rate of 0.5°C/min. From 600° C. to 370° C., the heat treatment was performed while supplying oxygen by repeatedly evacuating the inside of the firing furnace to about IX 10' torr and supplying oxygen gas until the pressure reached normal pressure. Note that the oxygen supply time per time was approximately 10 minutes.

Thereafter, the heat-treated wound body is placed in a vacuum container, and by making the inside of the container vacuum, epoxy is applied to the spaces 8 and through holes 4 in the superconductor wire 1 and between the superconductor wires 1. The epoxy resin 9 was impregnated with resin 9, and then heated to 100° C. to solidify the epoxy resin 9, and the entire wound body was integrated with the insulating sleeve 6 (FIG. 2-d) to obtain the desired superconductor coil.

When the superconducting properties of the superconducting coil thus obtained were measured, the critical temperature was 90°C, and the critical current density was 10°C.
．． A good result of 0OOA/c was obtained. Further, when a current to 3OO was passed through this superconductor coil and the intensity of the generated field 141 was measured, it was 0.11.

[Effects of the Invention] As is clear from the above embodiments, the superconductor coil of the present invention has a superconductor coil with a gap in the superconductor wire and a superconductor l1.
Since the space between the IT materials is filled and solidified with resin and made into a negative body, these movements due to electromagnetic force etc. are eliminated, and it is possible to stably maintain the 1/1 property of the superconducting coil at 1f, 7. be. Furthermore, since it is possible to uniformly and sufficiently supply oxygen to the oxide superconductor in the ¥JB process, it also has excellent superconducting properties.

[Brief explanation of the drawing]

Fig. 1 is a J perspective view schematically showing the winding state in the method for producing a superconductor coil of the present invention, and Fig. 2 shows the steps from the heat treatment step to the resin impregnation step in the method for producing the superconductor coil of the present invention. FIG. 1... Superconductor wire 2... Metal tube 3... Oxide superconductor 4... Penetration Hole 5.9...Epoxy resin 8...Gap Applicant: Toshiba Corporation Patent attorney Sasu Suyama - Figure 1

Claims (11)

[Claims] (1) A superconductor coil obtained by heat-treating a wound body of a superconductor wire in which a metal tube is filled with oxide superconductor powder, and a gap between the inner wall of the metal tube of the superconductor wire and the oxide superconductor. and a superconductor coil, characterized in that spaces between the superconductor wires of the wound body are filled and solidified with resin. (2) The superconductor coil according to claim 1, wherein an inorganic insulator is interposed between the superconductor wires of the wound body. (3) The superconductor coil according to claim 1 or 2, wherein the oxide superconductor is a perovskite-type superconductor containing a rare earth element. (4) The oxide superconductor contains rare earth elements, Ba and Cu in an atomic ratio of substantially 1:2:3. The superconductor coil according to any one of the items. (5) The oxide superconductor is LnBa_2Cu_3O
Claims 1 to 4 are characterized by having an oxygen-deficient perovskite structure represented by O_7_-_δ (Ln is at least one selected from rare earth elements, and δ represents an oxygen defect). The superconductor coil according to any one of the above. (6) processing a metal tube filled with oxide superconductor powder into a linear shape, and forming a plurality of through holes reaching the internal filling from the metal tube surface of the linear body obtained by this processing step,
a step of blocking the through hole with an organic substance and then winding it into a coil; a step of heat-treating the wound body to volatilize the organic substance; and a step of supplying oxygen from the through hole and the surface of the metal tube; 1. A method for manufacturing a superconductor coil, comprising the step of filling and solidifying a thermosetting resin between voids and superconductor wires in the superconductor wire of a wound body after heat treatment. (7) The method for manufacturing a superconductor coil according to claim 6, wherein the winding step is performed with an inorganic insulator interposed between the superconductor wires. (8) A patent characterized in that the heat treatment step of supplying oxygen to the oxide superconductor is performed by reducing the pressure of the atmosphere in which the wound body is placed and then supplying oxygen gas to a normal pressure state. A method for manufacturing a superconductor coil according to claim 6 or 7. (9) Manufacturing a superconductor coil according to any one of claims 6 to 8, wherein the oxide superconductor is a perovskite-type superconductor containing a rare earth element. Method. (10) The oxide superconductor contains rare earth elements, Ba and Cu in an atomic ratio of substantially 1:2:3. A method for manufacturing a superconductor coil according to any one of the items. (11) The oxide superconductor is LnBa_2Cu_3
Claims 6 to 10 characterized by having an oxygen-deficient perovskite structure represented by O_7_-_δ (Ln is at least one selected from rare earth elements, and δ represents an oxygen defect). A method for manufacturing a superconductor coil according to any one of the above.