JPH0255224A - Solution for producing oxide superconductor - Google Patents

Abstract

PURPOSE:To obtain an uniform oxide superconductor having good characteristics by dissolving a Cu compound, etc., in an alcohol solvent expressed by the general formula and homogeneously containing ingredients of oxide superconductor in a high concentration. CONSTITUTION:The title solution is formed by dissolving ingredients of oxide superconductor of Cu compound, etc., in an alcohol solvent. The above-mentioned alcohol is expressed by the general formula NR<1>R<2>(-R<3>-OH) (R<1> and R<2> are H atom or group selected from 1-6C alkyl group and aromatic group; R<3> is 1-6C alkylene group) and (-R<3>-OH) is preferably -CH2CH2OH, -CH2CH2CH2OH or -CH2CH(CH2)OH. The above-mentioned Cu compound, etc., includes alkoxide or beta-diketone chelate or beta-ketoester chelate of Cu, etc. Furthermore, the solute other than Cu is selected from Sc, Y, lanthanoid elements, Bi and Tl.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a solution for producing an oxide superconductor, and a method for producing an oxide superconductor using the aqueous solution.

(Prior art) In recent years, YBa2Gu+Oy and Bi25r2Ca2C have been developed as superconductors having a critical temperature of liquid nitrogen temperature wind-H.
:u3Qy.

Oxide superconductors such as T 12 Ba2 Ca2 Cu30y have been discovered and their practical application is expected.
Oxide superconductors are manufactured by sintering powder, but molding is difficult due to the brittleness characteristic of ceramics.Furthermore, film-like superconductors are also used in the field of superconductor applications, so they cannot be manufactured in a solution state. A method for manufacturing superconductors has been proposed.

For example, aqueous solutions of nitrates and acetates of metals contained in superconductors, salts of organic acids such as naphthenic acid and octylic acid, alkoxides, acetylacetonates, etc., can be mixed with alcohol,
Materials such as benzene, toluene, etc. - A solution dissolved in an organic solvent,
It has been proposed that a superconductor film be formed on a ceramic substrate by drying and firing after coating the substrate.

(Problems to be Solved by the Invention) However, a stable solution containing the necessary metal components at a high concentration has not been obtained, and after coating on a substrate, components with low solubility separate and precipitate during drying. There are problems in that a homogeneous superconductor cannot be obtained after firing, or that coating must be repeated many times in order to obtain a film of the required thickness.

So far, N(CH2 to l(□0 old,) in the solvent.

It has been proposed that the above problems can be solved by adding alcohol amines such as N1(((:N2(:H□0H)2).However, these amines dry slowly after being applied to the substrate. In addition, since it is necessary to dry at a high temperature, it is difficult to obtain a homogeneous coating film, and there are problems in that workability is poor.

(Means for Solving the Problems) The present inventor has developed a solution that contains superconductor components at a high concentration, is stable, has good wettability to the substrate, and dries quickly after application, and has good workability. As a result of research aimed at obtaining this, it was discovered that the above object could be achieved by adding a copper compound to a specific alcohol solvent.

(The present invention is based on the general formula %112(-R3-OH)
The present invention provides a solution for producing an oxide superconductor containing an alcohol as a solvent and a copper compound as a solute.

The alcohol used in the present invention is a group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 6 carbon fi, or an aromatic group. Number of carbons is 7
If it exceeds the above range, the boiling point will become high, which is inappropriate. Preferably, R1 and R2 are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In the general formula, R3 is an alkylene group having 1 to 6 carbon atoms. Preferably -R30H is -C11□(:N20H.

-CH2C1h CH20H, -CH20H (C:N3
) OH.

Particularly preferred is NN2CH2CH20H
.

N)I(CH3)CH2CH20H, NH(02N5
)CH2CH20H.

NH(n-C3H+)CH2CH20H,NH(i
-C3H7)C)I2C)120H.

N(CH3)2cH2cH20H, N(CH3)(C2
H5) CN2CtbOH.

N(CH3)(n-C:+H7)CH2CH20H.

N(CH+)(i-C:1H))C)12C)120H
, N(C2Hs), C:Toe)120H.

N(C2H5)(,n-GaH7)CN2Ci(zO)
i.

N(Cz)1s)(i-C3To)CN2CToOH,
N(n-03To)2cH2cH20HN(i-C:+
H+)2cH2cH20H and -C:H of the above compound
2C8208 group to -CH2CH2CH20H group or C
Examples include compounds substituted with H2C)l(CH3)OH group.

The copper compound used in the present invention is preferably an alkoxide, a β-diketone chelate, a β-ketoester chelate, or a mixture thereof. As the copper alkoxide, Cu(
OR')2 or Cu(0(CH2CH20)sR5)
z It is preferable that there is a note even if it is expressed. Here R
4 is a group selected from an alkyl group having 1 to 16 carbon atoms or an aromatic group, R5 is a hydrogen atom or carbon i n 1 to 1
The group m selected from six alkyl groups or aromatic groups is an integer from 1 to 6. The copper β-diketone chelate is preferably represented by Cu(R8(:0CIICOR6)-), and the copper β-ketoester chelate is preferably represented by Cu(R6COCHCOOR'l2), where R6 has 1 to 6 carbon atoms. an alkyl group,
A group selected from aromatic groups and perfluoroalkyl groups.

Particularly preferred copper compounds are Cu (OCH31,
.

(1:u (OC211512, 1n-c31+7o1
zcu, (i-Calltol 2Cu.

i n -C4H90) 2 C+] Seal 1-C4HJ)
zCu, (s-Cu2O3zcu.

(t-C411go) 2C11, (n-C5Hl +
ol acu, fi-(sH+ +01 zCu.

(n-CJ, ,0) 2Cu, CutCI3
GO to HCOCI+) 2. niu (C)I3CO
CHCOC,R512,Cu (C,115COCH(
:QC:aH51-, Cu (CIl, GOCIICO
O(:H, l,, Cu f II, COClIC0
OC2115+ 2. Cu 1n-C3H,0GOC
IICOCH31z, Cu (i-C,H,0CO
CH(:0CII312.Cu(n-C41190
COCHGOCH312,Cu (t-(:,H,0C
O(jlcOcl1312, Cu(i-C,H9
0COCHCOCI(zl z, Cu (S-C41
190COCH(:OCH312,C0(n-CsHl
1OCOCHCOCH,l 2. Cufi-C51
1,,0COCHCOCt1312゜Cu (n-C,
Il, 30(:0CtlCOCtl 312.C
u fcH-GOCIGOCF312(, u fcF3
GO is 1lcOcF3)2.

The solution of the present invention is prepared by adding and dissolving a copper compound and other components in predetermined amounts in the above-mentioned alcohol solvent. Components other than air conditioning can be used without particular limitation as long as they can be uniformly dissolved in the solvent, but alkoxides, metal complexes, metal salts, metals, etc. can be suitably used. The component added in metallic form reacts with and dissolves in the alcohol solvent of the above general formula. Therefore, in this case, it is necessary to use the alcohol solvent in excess of the amount consumed in this reaction.When adding in the form of 6-alkoxide, if the alkoxide is unstable on its own, dissolve it in a suitable solvent. You may also use Further, the alkoxide used at this time is preferably a low molecular weight alcohol alkoxide in order to increase the concentration of metal components in the solution.

In the solution of the present invention, a solvent other than the alcohol of the above general formula may be used in combination. Lower alcohols R' such as methanol and ethanol can be preferably used.
Alcohol represented by +O(:H2CH21POH (where R7 is an organic substituent having 1 to 16 carbon atoms or a hydrogen atom, P is an integer of 1 to 4), benzene, toluene, xylene, TIIF, DI, IFD AC, etc. be.

The composition of the solution of the present invention is not particularly limited as long as it is an oxide superconductor containing copper; for example, Y-Ba-(:u-
0 series old-3r-Ca-Cu-0 series, Tl-Ba-Ca-
Cu-0 series etc. can be manufactured.

Alkaline earth metal sources such as Ba, Sr, and Ca include metals, hydroxides, alkoxides, β-diketone complexes,
A β-ketoester complex or an organic acid salt such as acetic acid, octylic acid, or naphthenic acid is preferably used. Preferred Y sources include organic acid salts such as acetic acid, hydroxides, alkoxides, β-diketone complexes, β-ketoester complexes, and the like. Preferred Bi sources include organic acid salts such as octylic acid and naphthenic acid, ethoxide, impropoxide,
Examples include alkoxides such as normal butoxide. Preferred Tl sources include organic acid salts such as thallium acetate, alkoxides such as ethoxide, β-diketone spare, β-ketoester i (1 form), and the like.

When the hot liquid of the present invention is dried and the solvent is gradually removed, it becomes a homogeneous glass-like solidified body without separation and precipitation of specific components. Alternatively, by heating and firing in an oxygen atmosphere, a homogeneous oxide superconductor can be obtained.This solution exhibits good wettability to substrates such as ceramics and can be applied uniformly. For example, MgO, SrTl-03,A
lzO++Zr0z, LtNb03. A homogeneous superconductor film can be obtained on a substrate by applying it to a substrate made of a sintered product or sintered body such as silicon or sapphire, drying and firing. Materials other than those mentioned above can be used as the base material, and the shape of the base material can also be root-shaped or any other arbitrary shape. If necessary, it is also possible to increase the film thickness by gradually removing the solvent from the solution and concentrating the solution.6 Application.

The film thickness can also be increased by repeating drying and firing operations.

Further, by adding a suitable thickener to the solution of the present invention, spinning molding is possible and a linear superconductor can also be obtained. Further, since the solidified product obtained by removing the solvent from this solution is homogeneous in composition, it is also possible to obtain a superconductor powder for sintering by firing and then pulverizing the solidified product.

(Example) Example 1 2.75 g [20 mmol] of barium metal was dissolved in IOg of ethanol, and 3.08 g of yttrium n-butoxide ((n-C-H-0):+Yl (
10 mmol) and copper impropoxide ((i-C3
After adding 5.45 g (30 mmol) of LO13Cu) and stirring, N,N-dimethylaminoethanol (fc
I! , 12N(:112CI(□01) 110g was added and stirred at 60°C for 1 hour to obtain a homogeneous solution. This solution was concentrated under reduced pressure to a total amount of 20g, applied to a MgO single crystal plate, and heated at 110°C. When dried for 2 minutes, the solvent was easily volatilized and a blue glass-like homogeneous film was obtained.Next, this was heat-treated in air at 500°C for 5 minutes.

Then, the same coating, drying, and heating treatments were repeated three more times. Next, this was heated at 930°C in an oxygen atmosphere for 1
Baked for an hour. As a result, YBa was deposited on the MgO single crystal substrate.
A homogeneous superconductor film consisting of zCu30y was obtained. When the temperature dependence of the direct current resistance of this film was measured using the four-probe method, the critical temperature was found to be 84.

Examples 2 to 21 In place of barium metal, yttrium n-butoxide, 8-impropoxide, ethanol, and N,N-dimethylaminoethanol in Example 1, barium sources, yttrium sources, copper sources, and additions shown in Table 1 were used, respectively. An oxide superconductor film was obtained in the same manner as in Example 1 except that the solvent was used. Regarding Ba, Y, and Cu, the number of moles was the same as in Example 1, and 10 g of the solvent and additive solvent were used. All of the obtained films were YBazC
u:+0. Table 1 shows the critical temperatures (Tc) measured in the same manner as in Example 1.

Comparative Example N, When an attempt was made to explode the solution in the same manner as in Example 1 except that N-dimethylaminoethanol was not added, a homogeneous solution could not be obtained no matter how much heat was applied.

Examples 22 to 36 The strontium source (10 mmol) and calcium source (10 mmol) shown in Table 2 were added to the additive solvent (10 g) shown in Table 2.
After adding the bismuth source (bismuth 10 mmol) and copper source (15 mmol) in Table 2 and stirring, add the solvent (10 g) in Table 2 and stir at 60°C for 1 hour to form a homogeneous solution. Obtained. Thereafter, an oxide film was obtained on the MgO substrate in the same manner as in the example. This film is all made of BizSrzC
It was a homogeneous oxide superconductor consisting of azCusOy. The critical temperatures (Tel) measured in the same manner as in Example 1 are shown in Table 2.

Example 37 - Barium source (10 mmol), calcium! (Illll Damyl) was dissolved in the additive solvent (10 gl) shown in Table 3, and the thallium source (1.0 mmol) shown in Table 3 was added to it.
After adding copper tA (15 mmol) and stirring, the solvent (]Ogl shown in Table 3 was added and stirred at 60°C for 1 hour to obtain a homogeneous quenching solution.Then, the same procedure as in Example 1 was carried out to prepare MgOi An oxide film was obtained on the plate.This film was made of T12BazC.
It was a homogeneous oxide superconductor consisting of azCu:+Oy. The critical temperature (Te l
are shown in Table 3.

(Effects of the invention) The solution of the present invention is capable of homogeneously containing the components of the oxide superconductor at high concentrations, is stable, does not separate and precipitate specific components during drying, and is harmful. Since there are few impurities mixed in, it is possible to obtain a homogeneous oxide superconductor with good characteristics. Moreover, it has good wettability to substrates such as ceramics, and after being applied to these substrates, it can be dried and fired to form a homogeneous film on the substrate. In addition, when applied to a substrate, the solvent component easily evaporates, resulting in
Workability is good because it can be dried in a short time.

Claims (10)

[Claims] (1) A solution for producing an oxide superconductor containing an alcohol of the following general formula as a solvent and a copper compound as a solute. NR^1R^2(-R^3-OH) (R^1 and R^2 are a hydrogen atom, a group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, or an aromatic group, R^3 is an alkylene group having 1 to 6 carbon atoms). (2) -R^3-OH is -CH_2CH_2OH, -C
H_2CH_2CH_2OH, -CH_2CH(CH_
3) The solution of claim 1 which is OH. (3) The solution according to claim 1 or 2, wherein the copper compound is an alkoxide, a β-diketone chelate, or a β-ketoester chelate. (4) The solution according to any one of claims 1 to 3, which contains as a solute at least one component selected from the group consisting of scandium, yttrium, and litanoid elements. (5) The solution according to any one of claims 1 to 3, containing bismuth and/or thallium components as a solute. (6) Any one of claims 1 to 5 in which a component other than copper is added to the solvent in the form of an alkoxide, metal complex, metal salt, or metal.
A method for producing a solution of. (7) A method for producing an oxide superconductor, which comprises removing the solvent from the solution according to any one of claims 1 to 5 and then firing the solution. (8) A method for producing an oxide superconductor film, which comprises applying the solution according to any one of claims 1 to 5 to a base material, drying to remove the solvent, and then firing. (9) Base material is MgO, SrTiO_3, Al_2O_3
9. The manufacturing method according to claim 8, wherein the material is a single crystal or a sintered body selected from , ZrO_2, LiNbO_3, sapphire, and silicon. (10) A method for producing a linear oxide superconductor, which comprises adding a thickener to the solution according to any one of claims 1 to 5, spinning it, and then drying and baking it.