JPS63318025A - Manufacture of composite material of metal monooxide - Google Patents

Abstract

PURPOSE:To increase the mechanical strength and processing easiness without dropping electrical and magnetical properties by forming a film or wire of composite oxide type obtained through quick cooling and solidification of a superconductive composite oxide heated and melted, covering this film or wire with a metal heated and melted, and by cooling it rapidly and solidifying. CONSTITUTION:A superconductive composite oxide adjusted into specific compo sition is heated and melted into a fluid 1, which is supplied from a die 2 onto rolls 5-a, 5-b, whose cooling surfaces are update moving at a high speed, continu ously to be quick cooled and solidified. While this quick cooled and solidified superconductive composite oxide 7 is supplied continuously, a fluid 3 of heated and melted metal of specific composition is continuously supplied from a double tube die 4 so as to cover the superconductive oxide, to provide a multi-layer construction 8, which is now is quick cooled and solidified on rolls 6-a, 6-b whose cooling surfaces are update moving at a high speed. This accomplishes a superconductive composite material of oxide and metal with excellence in mechanical strength and processing easiness.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a composite material consisting of a superconducting composite oxide and a metal, and further relates to a superconducting composite oxide that has high strength and excellent workability. It concerns metal composite materials.

[Prior Art] Many substances that exhibit superconductivity have been known in the past, and among alloy systems, Nb-based alloys such as Nb, +Ge, and NbN exhibit a high superconducting critical temperature (hereinafter referred to as TC). N
b:+Ge has a TC of 23.6 10
Although it was reported about a year ago, [Applied Phys.
ics Letters, 23480 (1973)] Until recently, no substance with an extremely high TC was known.

On the other hand, in complex oxide systems, L! T! It is reported that 04 has a king C of 13.7[)lat
erials Research Bulletin,
8777 (1973)], its Tc is low and its practicality as a superconducting material is low.

Superconducting materials have a wide range of applications, and the main area of development is in magnet applications.Superconducting magnets have zero electrical resistance, so they can generate a strong magnetic field with only a small amount of power required for cooling. becomes possible. Therefore, it can be expected to be applied to fields that require a strong magnetic field, such as nuclear fusion, magnetic levitation trains, MHD power generation, accelerators, and motors. In the power field, it can be applied to generators, power storage, and power transmission lines.
For the electronics field, computer elements such as logic and memory (Josephson elements)
, a sensor that detects weak magnetic fields (quantum interference device)
It has applications in microwave devices that can be used in millimeter-wave band mixers and oscillators.

Superconducting materials used in such applications are required to have a high TC, and the search for materials is still ongoing. If a material with a high TC is developed, liquid nitrogen (boiling point 4.2K), which is cheap and abundant in resources, can be used as a refrigerant instead of liquid helium (boiling point 4.2K), which is expensive and problematic in terms of resources.
(boiling point 77.3K) can now be used, and its uses are expected to expand dramatically.

Recently, rare earth composite oxides based on Ba-La-Cu-0 have been developed.
It has been reported to have a high TC of 0 [Zeit
Schrift fur Physik, B 64°189 (19BB)], Y-Ba-Cu-0-based rare earth composite oxide is a material with even higher TC.
It has been reported that it has a high TC of [Ph
ysical Review Letters, 589
0B (1987)].

[Problems to be Solved by the Invention] Since superconducting composite oxides are brittle, molded products thereof have low strength against bending and twisting, and the range of processing and application thereof is limited.

Furthermore, although it is possible to process a molten superconducting composite oxide into a superconducting composite oxide film or wire by rapidly cooling it, the mechanical strength and processability of the created film are low. It is possible to improve the strength and workability by changing the composition of the melt or adding additives, but changing the composition of the melt or adding additives can improve the electrical and magnetic properties of the composite oxide. This leads to the drawback that the superconducting material is diluted, which is a practical problem as a superconducting material.

[Means for Solving the Problem] As a result of intensive research in order to solve the above-mentioned problems, the present inventors have developed a composite oxide film by rapidly solidifying a heated and melted superconducting composite oxide on a rotating roll. Alternatively, after forming into a wire, the superconducting composite oxide is coated with heated molten metal and rapidly solidified on a rotating roll to improve mechanical strength and workability without reducing the electrical and magnetic properties of the superconducting composite oxide. It was discovered that an excellent metal-oxide composite material can be produced, and the present invention was completed.

That is, the method for producing a composite material of the present invention includes a step of rapidly cooling and solidifying a heated and melted superconducting composite oxide to form a composite oxide film or wire; This is a method for manufacturing a metal-oxide composite material, which comprises a process of coating a metal and then rapidly solidifying it.

The method for manufacturing the metal-oxide composite material of the present invention will be described in detail below.

The oxide in the metal-oxide composite material of the present invention is characterized in that it is a superconducting composite oxide.

As a superconducting composite oxide, 1i-Ti-O system (TC1
3,7K), Ba-(Pb-B i )-〇 system (T
C13K>, Rb-W-0 type (TC6,4K), or copper-based composite oxide.

L r -T r -o system, Ba - (Pb-B i )
-○ series and Rb-W-0 series composite oxides have a low TC, so they are expensive and require the use of liquid helium, which is a scarce resource, which limits their practical use. On the other hand, since some copper-based composite oxides have more TO than liquid nitrogen, liquid nitrogen, which is a low-cost and abundant resource, can be used for cooling, making them more preferable from an industrial perspective.

The superconducting copper-based composite oxide has the general formula %, where Ml is at least one selected from Ca, 3r, and Ba, and M2 is SC, Y, and La.

Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, D
y, ) lo, Er, Tm, Yb, and LLJ. Furthermore, the composition ratios of a, b, and x are 0.5≦a≦3, 1.0≦b≦4.0, and 0.02≦X≦0.9. It is desirable because it creates things.

Next, a method for producing a superconducting composite oxide will be explained.

The method for producing a superconducting composite oxide of the present invention includes, for example, rare earth compounds such as rare earth oxides and rare earth hydroxides, alkaline earth metal compounds such as barium oxide, barium carbonate, strontium oxide, and strontium carbonate; 2
A method of mixing a predetermined amount of copper or a copper compound such as cupric carbonate and heating it to cause an in-phase reaction, rare earth elements, alkaline earth metals such as strontium and barium, and soluble compounds such as copper chlorides and nitrates. There is a method in which an aqueous solution of oxalate is added to a mixture of aqueous solutions of oxalate, coprecipitated, and then heated to react. Furthermore, after producing a mixture of two of these metal salt compounds by a coprecipitation method, a predetermined composite oxide can also be obtained by mixing the mixture with other metal compounds.

The heating reaction conditions vary depending on the composition, but 600'
It is preferable to carry out the reaction at a temperature of 0.5 to 900°C in a predetermined atmosphere for 0.5 to 24 hours.

Next, the metal used in the composite material of the present invention will be explained.

The metals used in the present invention are simple metals, alloys, intermetallic compounds, etc. that have high electrical conductivity and high thermal conductivity, and therefore, the metals of the present invention collectively refer to simple metals, alloys, intermetallic compounds, etc. Examples of metals used in the present invention include Cu, AQ, A
A single metal such as USA+, CU-AQ alloy, Aq-Ni alloy, AO-3r1 alloy, T1Cu2 intermetallic compound, etc. can be used. In particular, when a composite material is used as a superconducting IEi coil, it is preferable that the metal has high electrical conductivity and is non-magnetic for stabilization and countermeasures against fault current.

On the other hand, even if the metal has magnetism, it may contribute to stabilization due to the pinning effect of the magnetic flux, so it can be used in the present invention.

Next, an example of the method for manufacturing the metal-oxide composite material of the present invention is shown in FIG. However, the present invention is not limited thereto.

After heating and melting the superconducting composite oxide adjusted to a predetermined composition to form a fluid 1, it is continuously fed from a die 2 onto rolls 5-a and 5-b whose cooling surfaces move at high speed and are rapidly solidified. let Next, while continuously supplying rapidly solidified superconducting composite oxide 7, a fluid 3 made by heating and melting a metal of a predetermined composition.
is continuously supplied from the double-tube die 4 so as to cover the superconducting oxide to form a multilayer structure 8. After that, the multilayer structure is transferred to rolls 6-a and 6-b whose cooling surfaces move at high speed for renewal. Rapidly solidify on top.

For melting, the superconducting composite oxide or metal placed in a platinum die can be heated and melted into a fluid by resistance heating or high frequency heating. dice 2 and 4
A nozzle for discharging the melt, pressurized gas inlets 10 and 11 for applying pressure to the melt as necessary, and a superconducting composite oxide or metal supply port can be provided in the nozzle.

Next, the superconducting composite oxide or metal in the die in a molten and fluid state is ejected from the melt discharge port by applying pressure with an inert gas introduced from the gas inlet of the die. The ejected melt or multilayer structure is
For example, it is cooled and rapidly solidified on a chromium-plated rotating copper roll, and the cooling rate can be varied depending on the moving speed of the cooling body and the speed of ejecting the melt, and a higher cooling rate is desirable.

In the liquid ultra-quenching method, which is generally used to create amorphous materials,
Although the quenching rate is said to be 105 to 1107 de/sec, the present invention is not necessarily intended to create an amorphous body, and there is no problem even if the quenched solidified body contains a crystalline body. Therefore, the quenching rate is 1102 de/sec.
More than that is fine.

Next, the roll cooling method will be explained. As a roll cooling method, the centrifugal quenching method involves blowing the molten material onto the inside of a rotating cylinder, the twin roll method, which quenches the molten material by rolling it between two rolls, and the molten material is sprayed onto the outer circumferential surface of the rotating roll. A single roll method in which the wire is quenched by spraying it with water, a centrifugal quenching method in which the inside of a cylinder is filled with water or oil, and the molten material is blown out into the water or oil to produce a wire rod can be used.

Further, after obtaining the rapidly solidified product, a heating step can be added to crystallize the superconducting composite oxide and adjust the oxygen content. For this reason, for example, the material is heated by being held in a predetermined atmosphere for 0.5 hours to one week at a heating temperature of 400'C to 1200'C, and then cooled at a predetermined cooling rate.

[Example] The present invention will be explained in more detail with reference to Examples below.

Example 1 Yttrium oxide 22.6 (J, barium nitrate 104,
5 g of cupric oxide and 47.7 g of cupric oxide were mixed in a ball mill for 211 hours and heated in oxygen at a temperature of 900'C for 12 hours to obtain a composite oxide.

The obtained composite oxide was placed in a platinum die, melted by high-frequency heating, and then injected between two chromium-plated copper rotating rolls to form a rapidly solidified product. Immediately after the rapidly solidified composite oxide leaves the roll, a melt of A"0.9 CuO,1 alloy, which has been high-frequency melted in a double tube die, is injected onto the surface of the composite oxide solidified body. After coating, the molten metal-oxide multilayer structure was quenched between two rotating chromium-plated copper rolls using a twin-roll process.

The resulting multilayer structure was heated in an oxygen atmosphere at a temperature of 930 °C for 12 hours and at a temperature of 580 °C for 12 hours, and then cooled at a cooling rate of −50 °C/hour to obtain a composite material. .

The obtained multilayer structure was tape-shaped and had a composite oxide layer (300
It had a cross-sectional structure in which metal layers (150 μm) were laminated from both sides of the film. It was also possible to bend under stress, and the tensile strength in the longitudinal direction was 55 kmMmm2.

A part of the CuO, I Ag□, g alloy coating layer of the composite material was removed with nitric acid, an electrode was attached, and the electrical conductivity was measured in a cryostat using the four-terminal method. Tc (zero resistance temperature) was 93 k. It was found that it is a superconductor with .

Example 2 Neodymium oxide 33.7 (J, barium nitrate 104.5
g, cupric oxide 47.7 (]) were mixed in a ball mill for 2 hours, and then heated in oxygen at a temperature of 920'C for 2 hours to obtain a composite oxide.

Furthermore, a metal-oxide composite was created in the same manner as in Example 1 except that silver was used as the metal.

The composite was heated in an oxygen atmosphere at a temperature of 930'C(7) for 12 hours, at a temperature of 580'C for 12 hours, and then cooled at a rate of -50'C/hour to obtain a multilayer structure.

The obtained multilayer structure was tape-shaped and had a composite oxide layer (30
It had a cross-sectional structure in which metal layers (100 μm thick) were laminated from both sides of the metal layer (100 μm thick).

Moreover, the tensile strength of the multilayer structure was 35 kmcm'.

A part of the silver coating layer of the multilayer structure was removed with nitric acid, an electrode was attached, and the electrical conductivity was measured in a cryostat, and it was found to be a superconductor having a Tc (zero resistance temperature) of 91k.

[Effects of the Invention] As explained above, the method for producing a metal-oxide composite material according to the present invention provides a superconducting composite oxide-metal composite material with excellent mechanical strength and workability. This is extremely useful industrially as a superconducting material.

[Brief explanation of drawings]

Figure 1 is based on the twin roll method! &! 1 is a schematic diagram of an example of a manufacturing device. 1... Complex oxide fluid, 2... Dice, 3...
Metal melt, 4...Double pipe die, 11! Q, --
-1, d - 5-a, 5-b and 6-a, 6-b/e rotating roll, 7... Composite oxide solidified body, 8.9... Composite oxide-metal multilayer structure, 10.11
... Pressurized gas inlet.

Claims (1)

[Claims] A step of forming a composite oxide film or wire by rapidly cooling and solidifying a heated and melted superconducting composite oxide, and after coating the rapidly cooled and solidified composite oxide film or wire with a heated and molten metal. A method for producing a metal-oxide composite material comprising a step of rapid solidification.