JPH01282125A - Production of body covered by composite metal oxide having specified composition - Google Patents

Abstract

PURPOSE:To obtain the title body directly and inexpensively without synthesizing previously a powdery superconducting compound metal oxide by coating a soln. of each alkoxide of Bi, Sr and Ca in an org. solvent on a Cu oxide surface of a Cu base body, hydrolyzing the soln., and then calcining. CONSTITUTION:Each alkoxide of Bi, Sr and Ca is dissolved in an org. solvent such as isopropanol. In this case, preferred molar ratio of Bi:Sr:Ca in the alkoxide mixture is 1:1:1. The org. soln. is coated on a base body consisting of metallic Cu having Cu oxide on the surface by oxidizing the surface previously, and the alkoxides are hydrolyzed by standing in the atmospheric air, etc. The product is calcined then at, for example, 850 deg.C, in O2 atmosphere. Thus, an aimed body covered by a composite metal oxide having a specified compsn. is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing objects coated with composite metal oxides. More specifically, the present invention relates to a method of manufacturing an object coated with a thin film of a composite oxide of bismuth, strontium, calcium, and copper having a specific composition useful as a superconducting material. In particular, a composite oxide of bismuth, strontium, calcium, and copper with a specific composition has an ultra-R4 of 77 or more.
It is expected to be a substance that exhibits

[Conventional technology and problems]

In both methods of manufacturing thin films and wires of superconducting composite metal oxides, each metal component is physically pulverized and mixed in the form of a powder of each oxide, carbonate, etc. After that, a solid phase reaction is performed by firing, or each metal component is made into a homogeneous solution in the form of a water-soluble salt such as nitrate, hydrochloride, a-chloride, etc., and carbonate ion, hydroxide ion, By adding oxalate ions, etc.
A method is to coprecipitate each component in the form of insoluble hydroxide, carbonate, oxalate, etc., separate the precipitate, and sinter it, or
Alkoxide or each metal component.

First, superconductivity is obtained by dissolving a mixture of β-diketone complexes, β-diketoester complexes, or organic acid salts in an organic solvent to make a homogeneous solution, hydrolyzing it, separating the precipitate, and then firing it. Obtain composite metal oxide powder.

In the case of a thin film, there is a method in which a target is further prepared from the powder by a method such as hot pressing, and a thin film is formed on a substrate by a method generally called sputtering.

In the case of a wire, there is a method of obtaining a superconducting wire by filling this powder into a silver pipe as a sheath material, drawing it, and then heat-treating it in air or an oxygen atmosphere.

However, in either method, composite metal oxide powder must first be synthesized.

In order to manufacture a thin film by sputtering, expensive sputtering equipment, hot press equipment, etc. must be used, resulting in high costs.

In order to manufacture wire rods, oxide powder must be filled and wire-drawn, and as a result of the general property of oxide powder, it has extremely poor ductility, and wire diameters as small as necessary can be obtained through wire-drawing. Furthermore, since silver, which permeates oxygen, must be used as the sheath material, there are problems such as increased cost.

[Points of view, knowledge, and means related to solving problems] Therefore,
As a result of intensive studies, the present inventors have developed a method for obtaining composite metal oxide thin films or wires.

Among the metal components in the required composite metal oxide composition, at least one metal (in practice, lA) is used as a substrate, the surface is oxidized in advance, and an alkoxide (in practice, (alkoxides of bismuth, strontium and calcium) and this alkoxide mixture.

After applying it to the metal substrate whose surface has been oxidized and causing a hydrolysis reaction with moisture in the air, the firing time in air or oxygen is adjusted according to the thickness of the hydrolyzed product produced. It has been found that by doing this, it is possible to obtain an object, particularly a thin film or wire, whose surface at least has the desired composite metal oxide composition.

[Structure of the invention]

In the present invention, bismuth alkoxide, strontium alkoxide, and calcium alkoxide are dissolved in an organic solvent, and this solution is applied to a metal steel substrate whose surface is oxidized to darken it, and whose surface is copper oxide, and then hydrolyzed. Provided is a method for obtaining an object whose surface is coated with a composite metal oxide consisting of copper, bismuth, strontium and calcium, which comprises heating the object and then firing it.

In the method of the present invention, the ratio of bismuth alkoxide, strontium alkoxide, and calcium alkoxide in terms of metal is the same as the ratio of bismuth, strontium, and calcium in the target superconducting composite oxide, thereby achieving superconductivity. Copper objects with a complex oxide coating can be obtained. In a preferred embodiment, 1:
An alkoxide mixed solution containing Bi, Sr, and Ca in a molar ratio of 1:1 is used.

In the present invention, bismuth alkoxide is represented by the general formula Bi (OR') (OR2) (OR'), where R'' and R2°R1 are the same or different from C to C1.
This is a compound that is an alkyl group.

In the present invention, strontium and calcium alkoxides are represented by the general formula A(OR')(OR''), where A is Sr or Ca, and R1 and R2 are the same or different from each other. This is a compound that is an alkyl group.

In the present invention, the reason why a metallic copper substrate whose surface is oxidized and whose surface is oxidized steel is used is that copper is an essential element in the superconducting composite oxide and serves as its supply source, and the reason why the surface is oxidized is that This is to make the final heat treatment as easy as possible since the target substance is an oxide.

In the method of the present invention, the metallic copper substrate may be of any shape, such as a plate or a line, as long as the surface of the substrate of the required shape is made of metallic copper, or other metals or It may also be a substrate made of magnesium oxide, zirconium oxide, emerald, aluminum oxide, barium titanate, etc., on which the surface is made of metallic copper by plating or vapor deposition of steel.

In the present invention, the thickness of the hydrolysis products of bismuth, strontium, and calcium that are formed on metallic copper whose surface is previously oxidized and whose surface is copper oxide is not particularly limited, and the thickness of the hydrolysis products of bismuth, strontium, and calcium is not particularly limited, and the The thickness can be adjusted to any desired thickness depending on the number of times.

The firing time in the present invention is not limited because it depends on the thickness of the hydrolyzed product on the metallic copper whose surface is oxidized in advance and whose surface is oxidized steel, but it may be approximately 30 minutes to 5 hours.

The object having a superconducting coating can be obtained by the method of the present invention because it has a superconducting B1-5r-Ca-
When an alkoxide solution containing Bi, Sr, and Ca in the same quantitative ratio as the Cu composite oxide is applied to copper coated with copper oxide and then hydrolyzed and fired, the surface of the copper is

Only Bi, Sr, and Ca are included in a predetermined proportion, but only Cu is included.
A film of composite oxide whose content changes from the surface layer to the inner layer is formed. Therefore, by appropriately selecting the conditions for hydrolysis and firing, the desired superconducting composite oxide is definitely formed. This is because it can be done.

The conditions for this hydrolysis firing are determined mainly by experience and trial and error, but once these conditions are determined for an object of a specific shape, mass production can be carried out mechanically.

Superconductivity can be formed on the surface by selecting specific conditions.

〔Effect of the invention〕

As is already known, alkoxides of Bi, Sr, and Ca can be highly purified by distillation, recrystallization, etc. According to the method of the present invention, this highly purified alkoxide and high-purity copper are used. , an object coated with a superconducting composite metal oxide can be obtained directly and inexpensively without synthesizing the superconducting composite metal oxide powder in advance.

[Specific disclosure of the invention]

Example 1 Bismuth triisopropoxide Bi (OCR(CHj
) 21319.3 g, strontium diisopropoxide 5r (OCFI(C)1.)2) 210.2 g and calcium diisopropoxide Ca (OCH(CH
, ) Z ) 27.9 g was dissolved in 500 mQ of isopropanol to obtain a solution. This solution was mixed with a diameter of 0.01 mm+
Copper wire was heat-treated at 1000''C in an oxygen atmosphere for 1 hour to give an oxidized steel surface, and the process was repeated 10 times to allow it to be hydrolyzed by moisture in the air by leaving it in the air for 30 minutes. Cut a part of this copper wire using an optical H microscope!!!
The resulting hydrolysis product was found to be white and 1.8 microns thick.

After firing this product at 850°C for 1 hour in an oxygen atmosphere,
Furnace cooled. The superconducting critical temperature (Tc) of this wire was measured and found to be 75. In addition, quantitative analysis of the surface of this line was performed using an xIJA microanalyzer (XMA), and the results were as follows: Bi: Sr: Ca: Cu:
The O ratio was 1:1:1:2:5.5.

Example 2 Bismutri n-propoxide Bi(OCaHt) x
19.3g and strontium jetoxide 5r (0(1
: 328.88 g of 2H and 7.9 g of calcium gyropropoxide Ca (QCs Ht ) were dissolved in n-propatool 500aQ to form a solution. Furthermore, two copper plates 0.5 mm thick, 1 cm long and 1 cm wide, heat-treated at 1000 degrees Celsius for 30 minutes in an oxygen atmosphere to make the surface copper oxide are immersed in this solution, pulled up, and then hydrolyzed with moisture in the air. After repeating this process 5 times, I cut the sheet and observed the cross section with an optical g-microscope, and found that the thickness of the white hydrolyzed product was 1.2
It was a micron.

The remaining copper plate was fired at 870° C. for 1 hour in an oxygen atmosphere, and then cooled in a furnace. The superconducting critical temperature (Tc) of this plate was measured to be 70. In addition, quantitative analysis of the surface of this plate was performed using )l'lA, and it was found that Bi:Sr:
The ratio of Ca:Cu:O is 1:1:1:
The ratio was 1.9:5.4.

Example 3 Bismuth triethoxide si (QC2Hs)□17
．． 2g and strontium gyropropoxide 5r (OC
3H,), 10.28g and calcium jetoxide Ca (QC,H,), 5g of Q, and 500d of ethanol.
A solution was obtained. In this solution, add a diameter of 0.025+n
Plate copper to a thickness of 5 microns on the chain line of m, and further,
The wire was heat-treated at 1000'C for 30 minutes in an oxygen atmosphere to make the surface copper oxide, and then the wire was immersed, pulled out, and then hydrolyzed with moisture in the air, which was repeated five times. When a part of this line was cut and the cross section was observed with an optical microscope, the thickness of the white hydrolysis product was 1.7 microns. Further, this wire was fired in air at 800° C. for 1 hour, and then cooled in a furnace.

When we measured the superconducting critical temperature (Tc) of this wire, it was found to be 7
It was on 6th. Furthermore, quantitative analysis of the surface of this line was performed using XM
When I did A Te, Bi: Sr: Ca:
The ratio of Cu:O is 1:0.9:0.9:
1.8: 5.3.

Example 4 Bismuth triisopropoxide Bi (OCH(CHx
)2) 319.3g and strontium diisopropoxide 5r (OCR(CH,), 10.28g and calcium diisopropoxide Ca(OCR(CH,)
x) z) 7.9 g of z was dissolved in 500 mM of isopropanol to obtain a solution. Add this solution to the thickness III + 1
10cm copper on two magnesium oxide substrates 1cm wide
Plated to micron thickness, 1000'C under oxygen atmosphere
The process of immersing Fi, which was heat-treated for 1 hour to make the surface oxidized steel, then pulling it up and hydrolyzing it with moisture in the air, was repeated 10 times. When the cross section of one sheet was observed with an optical microscope, a white hydrolysis product was observed. The thickness was 3 microns. Furthermore, the remaining one sheet was fired at 850'C for 2 hours in an oxygen atmosphere and then cooled in a furnace.

The superconducting critical temperature (Tc) of this wire was measured and was 72
It was. In addition, quantitative analysis of the surface of this thin film was performed using XMA.
When I did this, Bi: Sr: Ca: C
The u:0 ratio was 1:1:1:2:5.5.

Claims (1)

[Claims] 1. Bismuth alkoxide, strontium alkoxide, and calcium alkoxide are dissolved in an organic solvent, and this solution is applied to a metallic copper substrate whose surface has been previously oxidized and whose surface is copper oxide, and then hydrolyzed. After doing this,
A method for obtaining an object whose surface is coated with a composite metal oxide consisting of copper, bismuth, strontium and calcium, which comprises firing. 2. The method according to claim 1, wherein the metal equivalent ratio of bismuth alkoxide, strontium alkoxide, and calcium alkoxide in the target superconducting composite metal oxide consisting of copper, bismuth, strontium, and calcium. A method characterized in that the amount ratio of bismuth, strontium and calcium is the same. 3. The method according to claim 2, wherein the alkoxide solution of bismuth, strontium, and calcium has a molar ratio of 1.
: A method containing 1:1 bismuth, strontium and calcium.