JPH01163919A - Manufacture of oxide superconductive formation - Google Patents

Abstract

PURPOSE:To rub together a material easily under a pressure, to form a superconductor over a curved surface of a base body or the like, and to obtain an oxide superconductive formation of an excellent property, by forming the superconductive formation while pressing the top surface of a rotary feeder to the base body or the like, while feeding the powder of the material or the like from the top surface of the rotary feeder. CONSTITUTION:When an oxide superconductive formation used for a power cable, a magnet, a power storage link, a magnetic seal, or the like, is manufactured, the temporarily baked powder 4 of an oxide superconductor, its powder, or the like, is fed from plural material feeding holes 3 of a specific diameter furnished at the top surface of a rotary feeder 1. Furthermore, a die 5 is rotated by a specific carrier gas, the temporarily baked powder 4 is made into a regulated paste and pressed in the die 5 by applying a specific pressure, and a pressed powder 9 is formed at the top surface 2. The pressed powder 9 is heat-treated in O2 at a specific temperature for a specific time, and then cooled at a specific speed to obtain an oxide superconductor. The feeder 1 is aqueezed on the curved surface of a base body 8 at a specific pressure, and a thrusted coverage substance 20 is formed easily by moving the base body 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing an oxide superconducting molded body used for power cables, magnets, power storage links, magnetic shields, etc.

[Conventional technology and its problems]

In recent years, (Lnl-XSrX)Cu04, (Ln,-,B
” +1) 2 Cu O4, LnBa*Cu307,
Oxide superconductors with a layered perovskite structure, such as LnBat-xSrxCusOy (wherein Ln is Y, Sc, or a rare earth element), have been found.

These oxide superconductors are much more economical than conventional metal superconductors which exhibit superconductivity at liquid He temperatures because they become superconducting above the liquid N2 temperature, and their use in various fields is being considered.

However, the above-mentioned oxide superconductors are brittle and cannot be plastically worked like metal materials, and in order to form them into a linear body, for example, a paste containing oxide superconductor powder is used as shown in Figure 4. The shaped material 27 is passed through the die 25 and coated on the base of the stainless steel wire 26, and this is coated with a
A method of heating to 0° C. to remove the binder material in the paste-like material 27, and then heating it to about 950° C. in a 0□ air current and slowly cooling it, or as shown in FIG. 5, the oxide superconductor powder 24 This is carried out by a method such as putting it into a die 35, pressing it into powder from the top and bottom with a punch 29, and then subjecting it to the same heat treatment as described above.

Incidentally, oxide superconductors have strong crystal anisotropy with respect to properties such as critical current density (hereinafter abbreviated as Jc), and it is considered extremely important to mold the superconductor so that a specific crystal orientation matches the current direction.

However, according to the conventional molding method as described above, the powder is molded with uniform orientation in all directions, so the entire molded product obtained is crystallographically unoriented, and therefore has a high Jc value etc. There was a problem of not being able to get things.

In addition, with conventional methods, there is a problem in that the processing methods are limited, such as compacting the powder with a die and drawing it into a paste form.Furthermore, it is difficult to form a superconductor film on a curved substrate. There was no suitable method to do this, which caused various practical problems.

[Means for Solving the Problems] The present invention was made in view of the above situation, and its purpose is to provide a method for manufacturing an oxide superconducting molded body having excellent superconducting properties.

That is, the present invention supplies a powder of an oxide superconductor or its precursor, or a paste prepared using these as raw materials, into a die or onto a substrate while rubbing them together under pressure.
It is characterized in that it is molded into a desired shape and then heated to a predetermined temperature.

In the present invention, an oxide superconductor such as 30 g of YBazCu or its precursor is used as a raw material, and the latter precursor includes oxides of elements constituting the superconductor,
Inorganic compounds such as carbonates, chlorides, and nitrates, organic compounds such as alkoxides and complex salts, or constituent metals and alloys thereof, as well as predetermined amounts of the above precursors are blended and calcined to form oxides. It is also possible to use a superconductor oxide or a superconductor oxide processed into powder.

In the present invention, when molding is performed by supplying raw material powder etc. from the tip surface of the rotary feeder and pressing the tip surface against the base etc., the raw materials can be easily rubbed together under pressure. A method using a rotating feeder is convenient for forming a superconductor into a curved substrate.

[Effect]

In the present invention, powders of oxide superconductors or their precursors, or pastes prepared using them as raw materials, are fed and molded while being rubbed together under pressure, so that the oxide superconductors have crystal orientations in a specific direction. are arranged and molded.

Furthermore, since the powder is rubbed together under pressure, the raw material powder is further refined and the adhesion between the powder and the substrate is improved.

As the raw material powder becomes finer, the number of crystal grains in each powder decreases, and the powder shape also increases in shapes other than spherical, such as scaly shapes, so the improvement in superconducting properties such as Jc becomes even more remarkable. You will be able to have a rainy day.

〔Example〕

The present invention will be explained in detail below using examples.

Example 1 FIG. 1 is a detailed explanatory diagram of the present invention. In the same figure,
1 is a rotating feeder.

Twenty raw material supply holes 3 with a diameter of 1 ma+ are provided on the tip surface 2 of the rotary feeder 1, and from these supply holes 3, calcined powder 4 of Y + B az Cu x Oq with an average particle size of 5 n is supplied to Ot gas. 500 (Example 1) or 2
．． Inner diameter 50mm rotating at 500rpm (Example 2)
Press fit into the die 5 of 200 kg/d to form a powder compact 9 of 50IIIφX20m',
Next, this compacted powder compact is O! After heating at 950°C for 6 hours in an air stream, the mixture was cooled to 300°C at a rate of 2"C/ll1n to produce an oxide superconducting molded body.

Comparative Example 1 A similar oxide superconducting molded body was produced by the same method as in Example 1 except that the die 5 was not rotated.

The critical temperature (hereinafter abbreviated as TC) and Jc in liquid nitrogen (77K) were measured for the oxide superconducting molded bodies produced in Examples and Comparative Examples thus obtained. The results obtained are shown in Table 1.

Table 1 * T-Tesla As is clear from Table 1, the method of the present invention (Example 1.2
), because the die was rotated, the crystal orientation of the powder was improved, and both TC and Jc showed higher values than the comparative method product (Comparative Example 1). In particular, the method of the present invention provides J
The decrease in , is small, and this tendency becomes larger as the die rotates faster (Example 2).

Embodiment 3 FIG. 2 is an explanatory diagram showing another embodiment of the present invention. In the same figure, 6 is a Ni-plated stainless steel wire of the base.

The rotary feeder 11 has raw material supply holes 13 with a diameter of 0.5 mm linearly provided on its tip surface 12 at intervals of III+1, and while rotating this feeder 11 at 1,00 Orp11, the average particle diameter is Y of 0.8μ
, Ba.

A paste 7 made by suspending calcined powder of Cu, O, in a machine binder is placed perpendicular to the axial direction of the feeder 11 and rotates at 10 rpm while traveling at a speed of 1 m/sin. 1 ■ Ni-plated stainless steel wire 6
A pressure of 2 kg/cd was applied to the top to form a crimped coating to a thickness of 0.1 mm, and then this coating 10 was heated in the atmosphere at
The binder was removed by IH heating at 600°C, then 0.
After heating to 950°C for 6 hours in an air stream, heat to 300°C for 2 hours.
It was cooled at a rate of °C/min to form an oxidized @lJMi conductive wire.

Comparative Example 2 An oxide superconducting wire was produced in the same manner as in Example 3, except that the same paste used in Example 3 was coated on the same Ni-plated stainless steel wire by the conventional extrusion method shown in FIG. Manufactured.

T and J in liquid nitrogen (77K) were measured for each of the oxide superconducting wires produced in this manner. The results are shown in Table 2.

Table 2 * T-Tesla As is clear from Table 2, the product manufactured using the method of the present invention (Example 3) shows higher values for both Tc and J than the product manufactured using the comparative method (Comparative Example 2), and especially The drop in J is small in a high magnetic field.

Embodiment 4 FIG. 3 is an explanatory diagram of another embodiment of the present invention. In the figure, 8 is a curved base body.

The average particle size of Y+Batcusot is 0.0000000000000 from a raw material supply hole (not shown) provided on the tip surface 2 of the rotary feeder 1.
While supplying the calcined powder of No. 8, the feeder 1 was moved over the curved substrate 8 while applying a predetermined pressure to the curved substrate 8 to cover it with the calcined powder. The above-mentioned calcined powder 4 was pressure-coated with high crystal orientation, and when this pressure-bonded coating 20 was subjected to a predetermined heat treatment, high Tc and Jc values comparable to those of Example 1 were obtained. .

〔effect〕

As described above, according to the present invention, the powder of the oxide superconductor or its precursor is molded with high crystal orientation, and by heating it to a predetermined temperature, the powder can be oxidized to have excellent characteristics such as J6. A superconducting molded body is obtained, which has remarkable industrial effects.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of an embodiment of the method of the present invention, and FIGS. 4-5 are explanatory diagrams of a conventional method. 1.11... Rotating feeder, 2.12... Tip surface, 3.13... Raw material supply hole, 5... Dice,
9...Powder compact, 10.20...Crimp covering body.

Claims (2)

[Claims] (1) Powder of an oxide superconductor or its precursor, or a paste prepared using these as raw materials, is fed into a die or onto a substrate while being rubbed together under pressure to form it into a desired shape. A method for producing an oxide superconducting molded body, which comprises heating to a predetermined temperature. (2) The oxide according to claim 1, characterized in that a rotary feeder is used to feed and mold a powder of an oxide superconductor or its precursor, or a paste prepared using these as raw materials. A method for manufacturing a superconducting molded body.