JP3771143B2 - Manufacturing method of oxide superconductor - Google Patents

Description

【００７６】
［分析・評価］
次に、上記にて得られた２種類の酸化物超電導導体について、Ａｇ箔の厚さを１０μｍとしたものを試料Ａ、Ａｇ箔の厚さを５０μｍとしたものを試料Ｂとして超電導特性の評価を行った。その結果を表２に示す。表２に示すように、バリア層を設けず、金属母材上に直接Ａｇ箔を貼り合わせた基材を用いた場合、Ａｇ箔の厚さが５０μｍの試料Ａの酸化物超電導導体は、Ｊｃが１３万Ａ／ｃｍ²であったが、Ａｇ箔の厚さを１０μｍとした試料Ａの酸化物超電導導体は、Ｊｃが３．２万Ａ／ｃｍ²であった。このＪｃの差はＡｇ箔の厚さが１０μｍでは、拡散したハステロイ構成元素（Ｎｉ，Ｃｒ，Ｍｏ等）がＡｇ箔を通過して酸化物超電導層に達したために、超電導特性が劣化したものと考えられる。
【００７７】
【表２】

【００７８】
（実施例２）
次に、テープ状のハステロイを金属母材として用い、この金属母材上にバリア層として厚さ５μｍのＰｔ箔を貼り合わせ、このＰｔ箔上に厚さ１０μｍの｛１１０｝＜１１０＞集合組織を有するＡｇ箔を貼り合わせた構成の基材を用いて、酸化物超電導導体を作製した。基材以外の拡散層及び酸化物超電導層の合成条件は、上記実施例１の試料Ａと同様にして作製した。これらの条件を表３に示す。尚、本例ではバリア層をＰｔ箔を貼り合わせることで形成したが、スパッタ法などによりＰｔからなる層を形成してバリア層とすることもできる。また、Ａｇ箔の集合組織もＡｇ箔を貼り合わせた後に、熱処理を施して形成しても良い。
【００７９】
【表３】

【００８０】
［分析・評価］
上記にて作製された酸化物超電導導体を、試料Ｃとして超電導特性の評価を行った。その結果を表４に示す。表４に示すように、金属母材とＡｇ箔との間にバリア層を形成した試料Ｃの酸化物超電導導体は、Ｊｃが１８万Ａ／ｃｍ²であり、上記実施例１の試料Ａと比較して大幅にＪｃが向上していることが確認された。これは、金属母材上に設けられたバリア層により効果的に、ハステロイ構成元素の拡散が抑制され、Ａｇ箔上に良好な結晶配向性を有する酸化物超電導層が形成されたことによると考えられる。
【００８１】
【表４】

【００８２】
【発明の効果】
以上詳細に説明したように、本発明によれば、テープ状の金属母材と、該金属母材の少なくとも一面側に形成された圧延集合組織を有するＡｇ層とを備えた酸化物超電導導体用基材と、前記酸化物超電導導体のＡｇ層の表層部にＣｕが拡散されて形成された拡散層と、前記拡散層上に形成された酸化物超電導層とを備えて構成されたことで、優れた強度と超電導特性を具備した酸化物超電導導体を提供することができる。
【００８３】
次に、本発明の酸化物超電導導体用基材は、テープ状の金属母材と、該金属母材の少なくとも一面側に形成された圧延集合組織を有するＡｇからなるＡｇ層とが備えられた構成とされたことで、従来のＡｇ基材の問題点であった強度の問題を解決したものである。また、金属母材上にＡｇを成膜または貼合わせる技術は、従来のクラッド材の製造に用いられている技術を応用することができるので、安価に高強度の基材を得ることができ、Ａｇ基材の利点を損なうことなく酸化物超電導体を製造することができる。
【００８４】
また、上記金属母材と、Ａｇ層との間に、バリア層を設けた構成とするならば、金属母材を構成する元素が、Ａｇ層や酸化物超電導層へ拡散するのを抑制することができるので、Ａｇ層の集合組織や酸化物超電導層の結晶組織を良好に保つことができ、Ａｇ層上に形成される酸化物超電導層の結晶配向性や結晶連続性を良好なものとすることが可能である。
【００８５】
次に、本発明の酸化物超電導導体の製造方法によれば、上記本発明の基材を用いるとともに、この基材のＡｇ層の表層部にＣｕが拡散された拡散層を形成し、この拡散層上に酸化物超電導層を形成する構成としたので、酸化物超電導層からＡｇ基材へのＣｕの拡散が抑制され、超電導特性に優れた酸化物超電導導体を容易に製造することができる。従って、本発明に係る製造方法によれば、超電導特性に優れ、かつ高強度の酸化物超電導導体を安価に製造することができる。
【図面の簡単な説明】
【図１】 図１は、本発明に係る酸化物超電導導体用基材の断面構造例を示す図であり、図１（Ａ）は、金属母材とＡｇ箔から構成された基材の例を示し、図１（Ｂ）は、金属母材とＡｇ箔との間にバリア層を有する例を示す。
【図２】 図２は、本発明に係る酸化物超電導導体の製造方法により製造することができる酸化物超電導導体の断面構造の一例を示す図であり、図２（Ａ）は、図１（Ａ）に示す構成の基材を用いた例を示し、図２（Ｂ）は、図１（Ｂ）に示す構成の基材を用いた例を示している。
【図３】 図３は、本発明に係る酸化物超電導導体の製造装置の全体構成を示す図である。
【図４】 図４は、図３に示す製造装置に備えられた原料ガス供給装置の構造例を示す構成図である。
【図５】 図５は、図３に示す製造装置に備えられたリアクタの構造例を示す斜視構成図である。
【図６】 図６は、図３に示す製造装置に備えられたリアクタの構造例を示す断面構成図である。
【図７】 図７は、従来の酸化物超電導導体の一例を示す断面図である。
【図８】 図８は、従来の酸化物超電導導体の他の例を示す断面図である。
【符号の説明】
Ｓ_A、Ｓ_B…酸化物超電導導体、ａ…金属母材、ｂ…Ａｇ箔（Ａｇ層）、ｃ…拡散層、ｅ…バリア層、３８、Ｔ、Ｔ_A、Ｔ_B…基材、ｄ…酸化物超電導層、Ａ，Ｂ，Ｃ…ＣＶＤユニット、３０Ａ…ＣＶＤ反応装置、３１Ａ…リアクタ、３２Ａ，３３Ａ，３７Ａ…隔壁、３４Ａ…基材導入部、３６Ａ…基材導出部、３８Ａ…境界室、３９Ａ…基材通過孔、４０…ガス拡散部、５３Ａ…原料ガス導入管、８０Ａ…ガス排気手段、Ｒ…基材搬送領域[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oxide superconducting conductor that can be used in the fields of superconducting power cables, superconducting magnets, superconducting energy storage, superconducting power generators, medical MRI apparatuses, superconducting current leads, and the like, and a method for manufacturing the same.
[0002]
[Prior art]
As a conventional method for producing an oxide superconductor, a mixed powder having a composition that can be converted into an oxide superconductor by heat treatment or oxide heat treatment is pressed into a cylindrical shape, and inserted into a silver tube to be drawn or rolled. In addition to solid-phase methods such as powder-in-tube method (PIT method), which is converted into a wire by performing a heat treatment process, it is continuous on a long base material such as metal tape by a vapor phase method such as laser vapor deposition or sputtering. In particular, a film forming method for forming an oxide-based superconducting layer is known.
[0003]
As shown in FIG. 7, the structure of an oxide superconducting conductor manufactured by a vapor phase method such as a laser deposition method or a CVD method is a YBaCuO-based oxide superconducting layer on the upper surface of a base material 191 made of a metal such as Ag. It is widely known that 193 is formed and a surface protective layer 195 made of Ag is formed on the oxide superconducting layer 193.
In order to obtain excellent superconducting characteristics in an oxide superconducting conductor produced by a vapor phase method such as laser vapor deposition or CVD, biaxial orientation of the oxide superconducting layer 193 produced on the substrate 191 is used. It is important to realize (in-plane orientation). For that purpose, it is preferable that the lattice constant of the base material 191 is made close to the lattice constant of the oxide superconducting layer 193 and the crystal grains constituting the surface of the base material 191 are arranged in a quasi-single crystal.
[0004]
Therefore, in order to solve this problem, as shown in FIG. 8, a polycrystalline intermediate layer 192 such as YSZ (yttria stabilized zirconium) is formed on the upper surface of a metal substrate 191 such as Hastelloy tape using a sputtering apparatus. And forming an oxide superconducting layer 193 such as a YBaCuO system on the polycrystalline intermediate layer 192, and further forming an Ag stabilizing layer 194 thereon to form an oxide superconducting conductor having excellent superconductivity. Various attempts have been made to manufacture. Alternatively, an Ag base material in which a texture is formed by rolling and heat treatment, and a Ni base material in which a texture is formed by rolling and heat treatment and further an oxide intermediate layer is formed have been studied.
[0005]
Among these, Ag has a low reactivity with the oxide superconducting layer 193 and is the only metal material that can directly form the oxide superconducting layer 193 on the base material 191. Furthermore, it is nonmagnetic and has low resistance. Since it also has the characteristic that it exists, the base material 191 itself can implement | achieve the wire structure which functions also as a stabilization layer.
[0006]
As the tape-shaped Ag base material in which the texture is formed by rolling and heat treatment, Ag {100 having a cubic texture in which the (100) plane is preferentially oriented in the base material surface and <001> is preferentially oriented in the longitudinal direction. } <001>, or Ag {110} <110> having a cubic texture in which the (110) plane is preferentially oriented in the longitudinal direction and <110> is preferentially oriented in the longitudinal direction, etc. have been developed. Among them, in consideration of lattice matching with the YBaCuO-based oxide superconducting layer, an oriented Ag base material of Ag {110} <110> is promising.
[0007]
[Problems to be solved by the invention]
In the oxide superconducting conductor in which the oxide superconducting layer 193 is formed on the polycrystalline intermediate layer 192 as shown in FIG. 8, the smoothness of the surface on which the oxide superconducting layer 193 is formed by the action of the polycrystalline intermediate layer 192. In-plane orientation is excellent, and a well-oriented oxide superconducting layer 193 can be obtained. ² It has been confirmed that the above high Jc can be obtained. Moreover, since Hastelloy is used as the metal tape, a wire rod with sufficient strength can be manufactured. However, the base material provided with the polycrystalline intermediate layer 192 needs to use an advanced and expensive technique such as ion beam sputtering for film formation, and at present, the base material production speed up to about 1 m / h. However, there is a problem that the manufacturing cost is extremely high.
[0008]
On the other hand, with an oriented Ag base material using a rolled Ag texture, the productivity of the base material can be increased, and the manufacturing cost is relatively low, which is promising. / Cm ² There has been almost no report that the above high Jc was obtained, and the lack of superconducting properties has been a problem. This is considered to be because the continuity of the oxide superconducting layer is impaired by the unevenness at the grain boundary of the Ag base material. In addition, when an Ag base material is used, Ag itself is a very soft metal and is further softened by being heated to a high temperature during the formation of the oxide superconducting layer. Therefore, an oxide using the Ag base material is used. In order to apply a superconducting conductor to a wire or the like, it is necessary to solve the strength problem.
[0009]
The present invention has been made to solve the above-mentioned problems, and uses an oxide-based base material, an oxide superconducting conductor having excellent strength and superconducting characteristics, a method for producing the same, and oxide superconducting. It aims at providing the base material for conductors.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, an oxide superconducting conductor of the present invention is an oxide comprising a tape-shaped metal base and an Ag layer having a rolling texture formed on at least one side of the metal base. It comprises a base material for a superconducting conductor, a diffusion layer formed by diffusing Cu in a surface layer part of an Ag layer of the base material, and an oxide superconducting layer formed on the diffusion layer. .
[0011]
That is, the oxide superconducting conductor of the present invention uses a double-structured base material provided with an Ag layer having a rolled texture on a metal base material, thereby significantly improving the strength compared to a conventional Ag base material. It is a thing. Moreover, since the diffusion layer in which Cu is diffused is formed in the surface layer portion of the Ag layer, it is possible to effectively suppress the diffusion of Cu from the oxide superconducting layer to the Ag base material. Owing to this layer, grain boundary growth on the surface of the Ag base material can be suppressed, so that the composition of the oxide superconducting layer is not disturbed or the continuity of the crystal is not impaired, and the oxide superconductivity having excellent superconducting characteristics. It can be a conductor.
[0012]
Next, in the oxide superconducting conductor of the present invention, the Ag layer preferably has a thickness in the range of 10 μm to 100 μm. If the thickness of the Ag layer is less than 10 μm, the constituent elements of the metal base material diffuse into the superconducting layer through the Ag layer. Moreover, when exceeding 100 micrometers, since the usage-amount of Ag is large and the cost of a base material becomes high, it is unpreferable.
[0013]
Next, the oxide superconducting conductor of the present invention may have a configuration in which a barrier layer is provided between the Ag layer and the metal base material. By adopting such a configuration, it is possible to suppress the elements constituting the metal base material from diffusing into the Ag layer or the oxide superconducting layer. Therefore, the Ag layer texture or the oxide superconducting layer crystal structure It is possible to keep the crystal orientation and crystal continuity of the oxide superconducting layer formed on the Ag layer favorable.
[0014]
Moreover, in the oxide superconducting conductor provided with the said barrier layer, the film thickness of the said Ag layer can be set as the structure made into 5 micrometers or more and 10 micrometers or less. That is, the barrier layer can prevent the elements constituting the metal base material from diffusing into the Ag layer or the oxide superconducting layer formed on the Ag layer. Therefore, according to this configuration, an oxide superconducting layer having good crystal continuity can be formed even if the Ag layer is thinned, and an oxide superconducting conductor excellent in superconducting characteristics can be provided. Further, in the oxide superconducting conductor provided with this barrier layer, if the thickness of the Ag layer is less than 5 μm, it is difficult to bond the Ag layer (Ag foil) to the barrier layer, which is not practical. Moreover, when exceeding 10 micrometers, since it leads to the increase in base-material cost, it is unpreferable.
[0015]
Next, the base material for oxide superconductor of the present invention is a tape for forming an oxide superconductor layer by chemically reacting a raw material gas of the oxide superconductor on at least one side to form an oxide superconductor. A tape-shaped metal base material, and an Ag layer made of Ag having a rolling texture formed on at least one side of the metal base material, and the film thickness of the Ag layer is 10 μm It is characterized by being 100 μm or less.
[0016]
That is, the base material for oxide superconducting conductors of the present invention has a double structure in which a layer made of Ag is formed on a metal base material, thereby solving the problem of strength that was a problem of conventional Ag base materials. It is a thing. In addition, since the technology for forming or bonding Ag on a metal base material can be applied to the technology used in the production of conventional clad materials, a high-strength base material can be obtained at low cost. An oxide superconductor can be manufactured without impairing the advantages of the Ag base material.
[0017]
Next, the base material for oxide superconductor of the present invention is a tape for forming an oxide superconductor layer by chemically reacting a raw material gas of the oxide superconductor on at least one side to form an oxide superconductor. A tape-shaped metal base material, an Ag layer made of Ag having a rolling texture formed on at least one side of the metal base material, and between the metal base material and the Ag layer And a thickness of the Ag layer is 5 μm or more and 10 μm or less.
[0018]
If the metal base material of the base material and the Ag layer are provided with a barrier layer, the constituent elements of the metal base material are heat treatment and oxide superconductivity for introducing a rolling texture into the Ag layer. Diffusion to the Ag layer side can be suppressed by heating for forming the layer. Therefore, if the base material for oxide superconducting conductors of this configuration is used, it is possible to prevent the crystal orientation and crystal continuity of the oxide superconducting layer from being impaired by such diffusion, so that excellent superconducting characteristics are provided. An oxide superconducting conductor can be realized.
[0019]
Next, the method for producing an oxide superconducting conductor according to the present invention includes an oxide superconducting conductor comprising a tape-shaped metal base material and an Ag layer having a rolling texture formed on at least one side of the metal base material. Forming a diffusion layer in which Cu is diffused in the surface layer of the Ag layer of the base material for the substrate, and forming an oxide superconducting layer by chemically reacting the raw material gas of the oxide superconductor on the diffusion layer It is characterized by including.
[0020]
By adopting such a configuration, the diffusion layer can suppress the diffusion of Cu from the oxide superconducting layer to the Ag base, and an oxide superconducting conductor excellent in superconducting characteristics can be easily manufactured. . In addition, the diffusion layer in which Cu is diffused does not need to use an advanced and expensive film formation technique like the polycrystalline intermediate layer such as YSZ, and can be easily performed by normal sputtering, vapor deposition, CVD method, or the like. Can be formed. Therefore, according to this configuration, an oxide superconducting conductor excellent in superconducting characteristics can be manufactured at low cost.
[0021]
Next, in the method for producing an oxide superconducting conductor of the present invention, the oxide superconducting thin film is formed by chemically reacting the raw material gas of the oxide superconducting conductor on at least one side of the moving tape-like substrate. A reactor for performing a reaction; a raw material gas supply means for supplying an oxide superconducting conductor raw material gas to the reactor; and a gas exhausting means for exhausting the gas in the reactor. The raw material gas supply means is provided with a raw material gas supply source for the oxide superconductor, a raw material gas introduction pipe for the oxide superconductor, and an oxygen gas supply means for supplying oxygen gas. The reaction generation chamber and the base material lead-out section are each partitioned through a partition, and a plurality of the reaction generation chambers are provided in series in the moving direction of the tape-shaped base material, and a base material passage hole is formed in each partition wall. A base material conveyance region passing through the base material introduction portion, the plurality of reaction generation chambers and the base material extraction portion is formed in the reactor, and a gas diffusion portion is provided in each of the plurality of reaction generation chambers. The plurality of reaction generation chambers are used as a film formation region, and are formed using a film formation apparatus in which the raw material gas introduction pipe of the oxide superconductor is connected to the reaction generation chamber via the gas diffusion portion. It is characterized by filming.
[0022]
With such a configuration, the diffusion layer and the oxide superconducting layer can be continuously formed by a plurality of reaction generation chambers, so that the oxide superconducting conductor can be efficiently manufactured. Can do. Therefore, it is possible to improve the product yield and reduce the manufacturing cost.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a base material for an oxide superconducting conductor according to the present invention, an oxide superconducting conductor, a manufacturing method thereof, and an apparatus used in carrying out this manufacturing method will be described with reference to the drawings.
[0024]
(Substrate for oxide superconducting conductor)
FIG. 1A is a diagram showing a cross-sectional structure of an embodiment of a base material for an oxide superconducting conductor according to the present invention, and FIG. 1B shows another base material for an oxide superconducting conductor according to the present invention. It is a figure which shows this embodiment. A base material 10 for an oxide superconducting conductor shown in FIG. 1A is composed of a metal base material 1 made of a high-strength metal material and an Ag foil (Ag layer) 2 bonded onto the metal base material 1. Has been. A base material 20 for an oxide superconducting conductor shown in FIG. 1B includes a metal base material 11, a barrier layer 13 formed on the metal base material 11, and an Ag foil ( Ag layer) 12. In FIGS. 1A and 1B, only the cross-sectional structure of the oxide superconducting conductor is shown, but it is actually a tape shape extending in a direction perpendicular to the paper surface.
[0025]
The metal base materials 1 and 11 are preferably made of a material excellent in high temperature strength such as Hastelloy (NiCrMo alloy), Ni, Inconel, and stainless steel. By using these metal materials as the metal base material, heat treatment for texture formation of the Ag layer, softening of the metal base material when heated to a high temperature to form an oxide superconducting layer, Diffusion of constituent elements of the metal base material is difficult to occur. Therefore, a good texture can be formed and maintained in the Ag layer, and a good crystal orientation and crystal continuity can be realized in the oxide superconducting layer. It is possible to produce an oxide superconducting conductor comprising Further, the thickness of the metal base materials 1 and 11 may be appropriately changed according to the purpose, but is preferably about 50 μm to 200 μm.
[0026]
The Ag foils 2 and 12 are made of Ag having a rolling texture. As the rolling texture of the Ag foils 2 and 12, a {100} <001> texture having a cubic texture in which the {100} plane is preferentially oriented in the longitudinal direction and <001> is preferentially oriented in the longitudinal direction, {110} surface on the substrate surface, {110} <110> texture having a cubic texture with <110> preferentially oriented in the longitudinal direction, {110} surface on the substrate surface in the longitudinal direction It is preferable that any one of {110} <001> textures having a cubic texture in which <001> is preferentially oriented. By using an oriented Ag base material having these textures, particularly when forming a YBaCuO-based oxide superconducting layer, the crystal lattice constant of the base material surface is made closer to the lattice constant of the oxide superconducting layer. Therefore, the crystallinity of the oxide superconducting layer to be formed can be improved, and excellent superconducting properties can be provided.
[0027]
Further, the rolled texture of the Ag foils 2 and 12 may be a texture formed by applying heat treatment after the rolled Ag foil is bonded to the metal base material 1 or the barrier layer 13. The rolled Ag foil may be preliminarily heat treated to form a rolled texture in the Ag foil, and the Ag foil having the rolled texture may be bonded to the metal base material 1 or the barrier layer 13. .
[0028]
The film thickness of the Ag foil 2 in the base material 10 not provided with the barrier layer is in the range of 10 μm to 100 μm. If the film thickness of the Ag foil 2 is less than 10 μm, the constituent elements of the metal base material 1 pass through the Ag foil 2 and diffuse into the oxide superconducting layer formed on the Ag foil 2, which is not preferable. Moreover, when exceeding 100 micrometers, the usage-amount of Ag increases and the cost as a base material becomes high and is unpreferable.
[0029]
On the other hand, in the base material 20 provided with the barrier layer 13, since the diffusion of the element of the metal base material 11 can be suppressed by the barrier layer 13, the thickness of the Ag foil 12 can be formed thinner. Therefore, the film thickness of the Ag foil 12 is 5 μm or more and 10 μm or less. If the thickness of the Ag foil 12 is less than 5 μm, it is difficult to bond the Ag foil 12 to the barrier layer 13, which is not preferable in practice. Moreover, when exceeding 10 micrometers, it will lead to the increase in base material cost, and is unpreferable.
[0030]
The barrier layer 13 shown in FIG. 1 (B) has an Ag foil formed by heat treatment for forming the rolling texture and heating for bonding the Ag foil to the metal base. It is provided in order to prevent the crystal orientation of the Ag foil from being impaired. Examples of the material constituting the barrier layer 13 include metals such as Pt, Au, and Cu, MgO, YSZ (yttria stabilized zirconia), and CeO. ₂ Etc. can be used.
[0031]
The film thickness of the barrier layer 13 may be an optimum film thickness as appropriate depending on the material constituting the barrier layer 13, but is preferably about 0.2 to 5 μm when a metal material is used, and when an oxide is used, It is preferable to set it as 0.1-0.2 micrometer. If the barrier layer 13 made of a metal material is less than 0.2 μm, the effect of suppressing the diffusion of elements of the metal base material 11 cannot be sufficiently obtained. If the barrier layer 13 exceeds 0.5 μm, the internal stress of the barrier layer It becomes easy to peel off. Even in the barrier layer 13 made of oxide, if the film thickness is less than 0.1 μm, the effect of suppressing the diffusion of the element of the metal base material 11 is not sufficient, and if it exceeds 0.2 μm, the formation of the barrier layer 13 is formed. In addition to an increase in cost required for the process, the barrier layer 13 may be cracked by stress when the base material is bent.
[0032]
According to the base materials 10 and 20 for the oxide superconducting conductor having the above configuration, the Ag foils 2 and 12 are formed on the metal base materials 1 and 11 made of a high-strength metal such as Hastelloy. The strength of the base material, which has been a problem with Ag base materials, can be greatly improved, and application to wire and the like can be facilitated. Moreover, since the Ag foils 2 and 12 as the surface layer have a structure having a rolling texture, the lattice matching with the oxide superconducting layer formed on the Ag foils 2 and 12 becomes good, An oxide superconducting conductor having excellent superconducting properties can be constructed. In addition, if the base materials 10 and 20 according to the present invention are used, an oxide superconducting layer can be formed directly on the Ag foils 2 and 12, so that the structure of the oxide superconducting conductor is simplified, and more There is also an advantage that manufacture is easy.
[0033]
(Oxide superconducting conductor and manufacturing method thereof)
Next, the manufacturing method of the oxide superconductor according to the present invention will be described below with reference to FIGS.
In the manufacturing method of the oxide superconducting layer of the present invention, the base material 10 or 20 for an oxide superconducting conductor shown in FIG. 1 (A) or FIG. 1 (B) is used. Then, a diffusion layer in which Cu is diffused is formed on the surface layer portion of the Ag foils 2 and 12 of the base materials 10 and 20, and then, the raw material gas of the oxide superconductor is chemically reacted on the diffusion layer. An oxide superconducting layer is formed.
[0034]
[Oxide superconductor]
FIG. 2 shows an example of a cross-sectional structure of the oxide superconducting conductor according to the present invention. Oxide superconductor S shown in FIG. _A 1 is an example of an oxide superconducting conductor using a base material having the structure shown in FIG. 1 (A), and a metal base material a and an Ag foil bonded to one surface side (the upper surface side in the figure) of the metal base material a. (Ag layer) Substrate T comprising b _A And an oxide superconducting layer d formed on the substrate T. The substrate T _A A diffusion layer c in which Cu is diffused in Ag is formed on the surface layer portion of the Ag foil b, and an oxide superconducting layer d is formed on the diffusion layer c.
[0035]
Oxide superconducting conductor S having the above configuration _A The thickness of the Ag foil b is preferably 10 μm or more and 100 μm or less. If the film thickness of the Ag foil b is less than 10 μm, the constituent elements of the metal base material a pass through the Ag foil b and diffuse into the oxide superconducting layer d, which is not preferable because it causes a decrease in superconducting characteristics. Moreover, when exceeding 100 micrometers, since the cost of a base material becomes high, it is unpreferable.
[0036]
On the other hand, the oxide superconductor S shown in FIG. _B 1 is an example of an oxide superconducting conductor using a base material having the structure shown in FIG. 1 (B), and a metal base material a and a barrier layer bonded to one surface side (the upper surface side in the figure) of the metal base material a. e and a base material T composed of Ag foil (Ag layer) b bonded on the barrier layer e _B The oxide superconducting conductor S shown in FIG. _A Is different.
[0037]
Oxide superconducting conductor S having the above configuration _B In this case, the barrier layer e can prevent the elements constituting the metal base material from diffusing into the Ag foil b and the oxide superconducting layer d on the Ag foil b. Therefore, according to this configuration, the oxide superconducting layer d having good crystal continuity can be formed even if the Ag foil b is thinned. Oxide superconducting conductor S provided with this barrier layer e _B If the thickness of the Ag foil b is less than 5 μm, it is difficult to bond the Ag foil b to the barrier layer e, which is not practical. Moreover, when exceeding 10 micrometers, it will lead to the increase in base material cost, and is unpreferable.
[0038]
As an element to be diffused in the diffusion layer c, an alloy mainly containing Cu may be used in addition to diffusing Cu element. For example, Cu added with Pt, Au, Pd, Ba, Y or the like can be used. The diffusion layer c can be formed by using a well-known film forming technique such as sputtering, vapor deposition, or CVD, and is highly advanced such as ion beam sputtering such as YSZ that has been conventionally used as an intermediate layer. There is no need to use expensive film formation technology. Further, by using a normal sputtering method, a CVD method, or the like, the formation speed can be greatly improved, and thus it is possible to manufacture easily and efficiently.
[0039]
The layer thickness of the diffusion layer is preferably in the range of 100 nm to 300 nm, and the Cu content of the diffusion layer c is 50 μg / cm. ² 300 μg / cm ² The following range is preferable. By controlling the diffusion layer c within these ranges, the crystal orientation and crystal continuity of the oxide superconducting layer b can be improved, and an oxide superconductor superior in superconducting characteristics can be provided. The thickness of the diffusion layer is less than 100 nm, or the Cu content is 50 μg / cm. ² In the case of less than the range, the amount of Cu contained in the diffusion layer is insufficient, so that it is not preferable because the diffusion of Cu from the oxide superconducting layer cannot be prevented, and the layer thickness exceeds 300 nm, or Cu Content is 300μg / cm ² In the case of exceeding, excess Cu is not preferable because it reacts with the oxygen gas used in forming the oxide superconducting layer and precipitates as an oxide such as CuO.
[0040]
The oxide superconducting conductor S of the present invention having the above-described configuration. _A , S _B Is provided with a diffusion layer formed by diffusing Cu in the surface layer portion of the Ag foil b of the base material, thereby preventing Cu contained in the oxide superconducting layer from diffusing into the Ag foil b. In an oxide superconducting conductor in which an oxide superconducting layer is formed on an Ag foil, 100,000 A / cm ² The above high Jc can be realized. In addition, the substrate T _A , T _B However, since it has a double structure in which an Ag layer b is formed on a metal base material a, it is an oxide superconducting conductor having excellent strength.
[0041]
[Manufacturing method of oxide superconductor]
This oxide superconductor S is described below. _A , S _B A manufacturing apparatus for manufacturing the semiconductor device and a method for manufacturing an oxide superconducting conductor using the manufacturing apparatus will be described with reference to FIGS. 3 to 6 show an example of an apparatus for manufacturing an oxide superconducting conductor according to the present invention. The manufacturing apparatus of this example includes three CVD units A having a substantially equivalent structure as shown in FIG. , B, and C are incorporated, and an oxide superconducting layer can be laminated on at least one surface of the tape-shaped substrate T in the reaction generation chamber 35A of each CVD reactor 30A.
[0042]
This apparatus for manufacturing an oxide superconducting conductor has a cylindrical quartz reactor 31A with both horizontally long ends closed. As shown in FIG. 5, the reactor 31A is divided into a base material introduction part 34A, a reaction generation chamber 35A, and a base material lead-out part 36A in order from the left side of FIG. 5 by partition walls 32A and 33A. The reaction generation chamber 35A is divided into a plurality of (in the drawing, three divisions) by a plurality of dividing walls 37A (four in the drawing) provided between the two, and each has a substantially equivalent structure, Two boundary chambers 38A are defined between adjacent reaction generation chambers 35A and 35A (between adjacent partition walls 37 and 37). Accordingly, the reactor 31A is provided with a plurality of (three reaction generation chambers in the drawing) in series in the moving direction of the tape-shaped substrate T that the reaction generation chamber 35A is sent to the substrate conveyance region R described later. It will be. The material constituting the reactor 31A is not limited to quartz but may be a metal having excellent corrosion resistance such as stainless steel.
[0043]
As shown in FIGS. 5 and 6, passage holes 39 </ b> A through which a long tape-like base material T can pass are formed at the lower center of the partition walls 32 </ b> A, 37 </ b> A, 37 </ b> A, 37 </ b> A, 37 </ b> A, 33 </ b> A. A base material transport region R is formed inside the reactor 31A so as to cross the center. Further, an introduction hole for introducing the tape-shaped base material T is formed in the base material introduction portion 34A, and a lead-out hole for leading the base material T is formed in the base material lead-out portion 36A. . In addition, the peripheral portions of the introduction hole and the lead-out hole are sealed to close the gaps between the holes while allowing the base material T to pass therethrough so as to keep the base material introduction part 34A and the base material lead-out part 36A in an airtight state. A stop mechanism (not shown) is provided.
[0044]
As shown in FIG. 5, a substantially pyramid-shaped gas diffusion section 40 is attached to the ceiling of each reaction generation chamber 35A. These gas diffusion portions 40 are connected to the gas diffusion member 45 attached to the reactor 31A and the ceiling wall 44 of the gas diffusion member 45, and supply the raw material gas of the diffusion layer or the oxide superconductor to the gas diffusion member 45. The gas inlet pipe 53A and a slit nozzle (not shown) provided at the tip of the gas inlet pipe 53A are provided. The bottom surface of the gas diffusion member 45 is an elongated rectangular opening 46A, and the gas diffusion member 45A communicates with the reaction generation chamber 35A through the opening 46A.
[0045]
As shown in FIG. 3, a cutoff gas supply means 38B is connected to the ceiling portion of the boundary chamber 38A via a supply pipe 38C, and the cutoff gas supply means 38B is a reaction generation chamber 35A, 35A on both sides of the boundary chamber 38A. A shutoff gas for shutting off each other is supplied, and the supply pipe 38 </ b> C is connected to the boundary chamber 38 </ b> A via a shutoff gas ejection portion. For example, argon gas is selected as the blocking gas.
[0046]
On the other hand, below each reaction production | generation chamber 35A and boundary chamber 38A, as shown in FIG. 6, an exhaust chamber penetrates each reaction production chamber 35A and boundary chamber 38A along the length direction of the base material conveyance area | region R. 70A is provided. In the upper part of the exhaust chamber 70A, as shown in FIG. 5, elongated rectangular gas exhaust holes 70a, 70a are provided along the length direction of the tape-like substrate T passed through the substrate transport region R. It is formed on both sides of the base material T so as to penetrate the reaction generation chamber 35A and the boundary chamber 38A, and the gas exhaust holes 70a, 70a are provided on either side of the base material conveyance region R of the partition walls 32, 33, 37. The end is in a penetrating state.
Further, a plurality of (seven in the drawing) exhaust pipes 70b are connected to the lower part of the exhaust chamber 70A, and these exhaust pipes 70b are connected to a pressure adjusting device 72 having a vacuum pump 71 shown in FIG. It is connected.
[0047]
Further, gas exhaust means is formed by an exhaust chamber 70A in which gas exhaust holes 70a and 70a are formed, a plurality of exhaust pipes 70b having exhaust holes 70c and 70e, a valve 70d, a vacuum pump 71, and a pressure adjusting device 72. 80A is configured. The gas exhaust means 80A having such a configuration can quickly exhaust gases such as source gas, oxygen gas, inert gas, and shut-off gas inside the CVD reactor 30.
[0048]
A heater 47A is provided outside the reactor 31A as shown in FIG. In the example shown in FIG. 3, the heater 47A is continuous over the three reaction generation chambers 35A. However, the heater 47A has a structure independent of the reaction generation chambers 35A of the respective CVD reactors 30. Is also possible. Further, the base material introduction part 34A of the reactor 31A is connected to the inert gas supply source 51A, and the base material lead-out part 36A is connected to the oxygen gas supply source 51B.
[0049]
As shown in FIG. 3, each source gas introduction pipe 53A connected to the ceiling wall 44 of the gas diffusion section 40 provided in the CVD unit A is supplied with a source gas for a diffusion layer described later via a gas mixer 48 described later. It is connected to a source gas vaporizer (source gas supply source) of the supply means 50a. Each source gas introduction pipe 53A connected to the ceiling wall 44 of each gas diffusion section 40 provided in the CVD units B and C is connected to the source gas supply means 50b of the oxide superconductor via the gas mixer 48. It is connected to a source gas vaporizer (source gas supply source).
[0050]
The diffusion layer raw material gas supply means 50a and the oxide superconductor raw material gas supply means 50b are the raw liquid supply device 65, liquid raw material supply device 55, and raw material solution vaporizer (raw material gas supply source) 62 shown in FIG. And is schematically configured. The vaporizer 62 accommodates a distal end portion (lower portion in the drawing) of a liquid raw material supply device 55 described later. In addition, a heater 63 is attached to the outer peripheral portion of the vaporizer 62, and a raw material gas is obtained by heating the raw material solution 66 supplied from the liquid raw material supply device 55 to a desired temperature by this heater 63 to vaporize it. It is supposed to be.
A heat retaining member 62 </ b> A is installed on the inner bottom of the vaporizer 62. The heat retaining member 62A may be any material as long as it is a material having a large heat capacity and does not react with the liquid raw material 66, and a metal thick plate is particularly preferable. Stainless steel, Hastelloy, Inconel, etc. are preferred.
[0051]
As shown in FIG. 4, the liquid raw material supply device 55 is schematically configured by a tubular raw material solution supply unit 56 and a cylindrical carrier gas supply unit 57 provided so as to surround the outer periphery of the supply unit 56. It has a heavy structure.
The raw material solution supply unit 56 supplies a raw material solution 66 sent from a raw solution supply device 65 described later into the vaporizer 62. The carrier gas supply unit 57 is for flowing the carrier gas for injecting the raw material solution 66 into the gap with the raw material solution supply unit 56. A carrier gas supply source 60 is connected to an upper portion of the carrier gas supply unit 57 via a carrier gas MFC (flow rate regulator) 60a, and the carrier gas supply unit 57 (gap with the raw material solution supply unit 56) is connected. A carrier gas such as argon gas, helium gas, nitrogen gas, etc. can be supplied.
[0052]
Further, the inside of the vaporizer 62 is divided into two in the vertical direction by the partition plate 62a, and the divided region is communicated with the lower side of the partition plate 62a, and the raw material gas passes through the lower communication portion of the partition plate 62a. It is configured so that it can flow to the connecting portion 53A through which the previous gas introduction pipe 53 is connected.
[0053]
In the liquid raw material supply device 55 described above, when the raw material solution 66 is fed into the raw material solution supply unit 56 at a constant flow rate and the carrier gas is fed into the carrier gas supply unit 57 at a constant flow rate, the raw material solution 66 is supplied from the raw material solution supply unit 56. The carrier gas flows from the tip of the carrier gas supply portion 57 on the outer peripheral side of the tip portion, but when the gas is blown out from the tip portion 59, the raw material solution 66 is brought into the vaporizer 62 together with the carrier gas. The gas is heated and vaporized while moving inside the vaporizer 62 until it reaches the bottom, and is used as a raw material gas. Further, the heat retaining member 62A installed at the bottom of the vaporizer 62 is reached, and further vaporization is performed by the heat retaining member 62A, whereby the raw material solution is completely vaporized to be a raw material gas. In the structure of the present embodiment, since the raw material solution is not atomized from the front end portion of the raw material solution supply unit 56, but only by mixing with heating and carrier gas, the raw material solution is made into the raw material gas. It is preferable that the liquid source does not collide with the inner wall of the vaporizer 62 until the liquid source is vaporized into the source gas.
[0054]
A raw solution supply device 65 is connected to the raw material solution supply unit 56 of the liquid raw material supply device 55 through a connection pipe 67 provided with a pressurized liquid pump 67a. The stock solution supply device 65 includes a storage container 68 and a purge gas source 69, and a raw material solution 66 is stored inside the storage container 68. The raw material solution 66 is sucked by the pressurized liquid pump 67a, the flow rate thereof is adjusted by the MFC 67b, and the raw material solution 66 is transported to the raw material solution supply unit 56.
[0055]
Further, as shown in FIG. 3, a tension drum 76 and a delivery drum for supplying the tape-shaped substrate T to the CVD reactor 30A are provided on the side portion side (previous stage side) of the substrate introduction portion 34A of the reactor 31A. 77 is provided. The tension drum 76 and the delivery drum 77 are configured to be rotatable forward and backward. Further, a tension drum 73 for winding the tape-shaped substrate T that passes through the substrate conveyance region R in the reactor 31A, and a winding on the side portion side (rear stage side) of the substrate lead-out portion 36A of the reactor 31A A base material transport mechanism 75 including a take-up drum 74 is provided. The tension drum 73 and the take-up drum 74 are also configured to be rotatable forward and backward.
[0056]
Next, a diffusion layer in which Cu is diffused is formed on the tape-shaped substrate T using the oxide superconducting conductor manufacturing apparatus having the CVD units A, B, and C configured as described above. The case where an oxide superconducting conductor is manufactured by forming an oxide superconducting layer on the layer will be described.
[0057]
In order to manufacture an oxide superconductor using the manufacturing apparatus shown in FIGS. 3 to 6, first, a tape-shaped substrate T, a raw material solution for a diffusion layer, and a raw material solution for an oxide superconductor are prepared. As this base material T, the thing of the structure shown in FIG. 1 mentioned above can be used.
[0058]
The raw material solution for generating the diffusion layer by the CVD reaction is preferably one in which the metal complex constituting the diffusion layer is dispersed in a solvent. Specifically, when forming a diffusion layer made of Cu, Cu (thd) ₂ And Cu (DPM) ₂ Or the like dissolved in a solvent such as tetrahydrofuran (THF), toluene, isopropanol, diglyme (2,5,8-trioxononane) can be used. (Thd = 2,2,6,6-tetramethyl-3,5-heptanedione)
[0059]
Further, as an element to be diffused in the diffusion layer c, an alloy mainly containing Cu may be used in addition to diffusing Cu element. For example, Cu to which Pt, Au, Pd, Ba, Y or the like is added can be used. When these are diffused, a metal complex of the element to be added may be added to the raw material solution. The diffusion layer c can be formed by a CVD method as in the manufacturing method of the present embodiment, or can be formed by using a well-known film forming technique such as a sputtering method or a vapor deposition method, and has conventionally been used as an intermediate layer. In addition, it is not necessary to use an advanced and expensive film forming technique such as an ion beam sputtering method such as YSZ. Further, by using a normal sputtering method, a CVD method, or the like, the formation speed can be greatly improved, and thus it is possible to manufacture easily and efficiently.
[0060]
The raw material solution for generating the oxide superconductor by the CVD reaction is preferably one in which the metal complex constituting the oxide superconductor is dispersed in a solvent. Specifically, Y ₁ Ba ₂ Cu _Three O _7-x When a Y-based oxide superconducting layer having the following composition is formed, Ba-bis-2,2,6,6-tetramethyl-3,5-heptanedione-bis-1,10-phenanthroline (Ba (thd) ₂ ・ Phen ₂ ) And Y (thd) ₂ And Cu (thd) ₂ Metal complexes such as phen = phenanthroline, Y-bis-2,2,6,6-tetramethyl-3,5-heptanedionate (Y (DPM) _Three ) And Ba (DPM) ₂ , Cu (DPM) ₂ A metal complex such as can be used.
[0061]
The oxide superconducting layer includes La, in addition to the Y-type. _2-x Ba _x CuO _Four La series represented by the composition formula, Bi ₂ Sr ₂ Ca _n-1 Cu _n O _{2n + 2} Bi series represented by the composition formula (n is a natural number), Tl ₂ Ba ₂ Ca _n-1 Cu _n O _{2n + 2} Many types of oxide superconducting layers are known, such as those of the Tl system represented by the composition formula (n is a natural number), so the above CVD method is carried out using a metal complex salt corresponding to the target composition do it.
Here, for example, when manufacturing an oxide superconducting layer other than Y-based, triphenylbismuth (III), bis (dipivalloymethanato) strontium (II), bis (di (di)) depending on the required composition system. A metal complex salt such as pivalloymethanato) calcium (II) or tris (dipivalloymethanato) lanthanum (III) can be used as appropriate for the production of each oxide superconducting layer.
[0062]
Next, the prepared raw material solution is stored as the raw material solution 66 in the storage container 68 of the raw liquid supply device 65 shown in FIG. 4 and connected to the liquid raw material supply device 55. In this example, the source gas supply means 50a for the diffusion layer is connected to the CVD unit A, and the source gas supply means 50b for the oxide superconductor is connected to the CVD units B and C, respectively.
[0063]
And if the tape-shaped base material T was prepared, this will be sent to the base material conveyance area | region R in the manufacturing apparatus of an oxide superconducting conductor from the base material introduction part 34A by the base material conveyance mechanism 78 at a predetermined moving speed. It winds up with the winding drum 74 of a base material conveyance mechanism. Further, the substrate T in the reaction generation chamber 35A is heated to a predetermined temperature by the heater 47A. Next, when the tape-shaped substrate T is fed into the reactor 31A, the raw material solution 66 is supplied from the storage container 68 to the flow rate of about 0.1 to 10 ccm by the pressurized liquid pump 67a provided in the raw material gas supply means 50a and 50b. Then, the liquid is fed into the raw material solution supply unit 56 and at the same time, the carrier gas is fed into the carrier gas supply unit 57 at a flow rate of about 200 to 550 ccm. The vaporizer 62 is heated to a temperature equal to or higher than the vaporization temperature of the raw material solution 66.
[0064]
Then, the raw material solution 66 on the mist having a constant flow rate is continuously supplied into the vaporizer 62, and is heated and vaporized by the heater 63 to become a raw material gas. This raw material gas is converted into the CVD unit A, The gas is continuously supplied to the gas diffusion portions 45 of B and C.
Next, the raw material gas moved to the reaction generation chamber 35A moves from the upper side to the lower side of the reaction generation chamber 35A, reacts on the heated substrate T, and deposits the reaction product, and diffuses in the CVD unit A. Even when the layer is formed on the substrate T, in the CVD unit B, an oxide superconducting layer is formed on the diffusion layer, and in the CVD unit C, an oxide superconducting layer is formed on the oxide superconducting layer. At this time, the control means 82A controls the gas partial pressure independently for each of the CVD units A, B, and C, and the source gas supply means 50a, so as to maintain a predetermined gas partial pressure in each reaction generation chamber 35A. 50b and 50b are controlled. At this time, the control means 82A determines that the gas partial pressure in the reaction generation chamber 35 on the downstream side in the movement direction of the tape-shaped substrate T is lower than the gas partial pressure in the reaction generation chamber 35 in the movement direction of the tape-shaped substrate T. It is preferable to control the source gas supply means 50a, 50b, and 50b so as to be higher. Then, the base material T on which these layers are formed is wound on a winding drum 74. After the oxide superconducting layer is formed, heat treatment for adjusting the crystal structure of the oxide superconducting thin film may be performed as necessary.
[0065]
Finally, when a stabilization layer made of silver or the like is further formed on the oxide superconductor S formed as described above by sputtering or vapor deposition, it is equivalent to the oxide superconductor S having the stabilization layer. The oxide superconducting conductor can be obtained. The stabilization layer can also be formed by CVD in one or more of the reaction generation chambers 35A of the manufacturing apparatus shown in FIGS. With such a configuration, the oxide superconducting conductor provided with the stabilizing layer can be continuously manufactured in the manufacturing apparatus.
[0066]
If the oxide superconductor S is manufactured using the apparatus having the structure shown in FIGS. 3 to 6, the oxide superconductor including the metal intermediate layer and the stabilization layer is manufactured by moving the base material T once. can do. Even in the oxide superconducting conductor obtained in this example, since the metal intermediate layer and the oxide superconducting layer having an appropriate thickness are stacked with the transport speed of the base material T being in an appropriate range, as described above. It is an oxide superconducting conductor with excellent superconducting properties.
[0067]
3 to 6, the substrate T is repeatedly moved back and forth between the delivery drum 77 and the take-up drum 74, and the oxide superconducting layer having four or six layers is stacked. An oxide superconductor may be manufactured by stacking. In the above example, the metal intermediate layer is formed in the reaction generation chamber 35A of the first stage (CVD unit A), and the oxide is formed in the reaction generation chamber 35A of the second and third stages (CVD units B and C). Although the case where the superconducting layer is formed has been described, the manufacturing method using the manufacturing apparatus of this example is not limited to this method. For example, in a state where all the three reaction generation chambers 35A are assigned to the formation of the metal intermediate layer, the metal intermediate layer is first formed on the substrate T while moving the substrate T, and the film having the required length is formed. After finishing, this time, the source gas supply means is changed in the three reaction generation chambers 35A so that the oxide superconducting layer can be formed, and the rotation directions of the delivery drum 77 and the winding drum 74 are reversed to form the base material. T may be moved from the base material lead-out part 36A side toward the base material introduction part 34A side, and an oxide superconducting layer may be formed on the metal intermediate layer formed on the base material T. it can.
[0068]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to these Examples.
Example 1
[Liquid material and substrate]
In this example, an oxide superconducting conductor using a tape-like Hastelloy as a metal base material and using a base material in which an Ag foil having a {110} <110> texture formed thereon is bonded to the metal base material. Was made. In this example, ^W 10mm x ^L 50mm x ^t Two types of base materials were used, in which a 0.09 mm metal base material and 10 μm and 50 μm thick Ag foil were bonded together. In this example, the Ag foil having a texture formed thereon is used. However, the Ag rolling night may be bonded to a metal base material and heat treated thereto to form the texture.
[0069]
First, Y ₁ Ba ₂ Cu _Three O _7-x As a raw material solution for CVD, Ba-bis-2,2,6,6-tetramethyl-3,5-heptanedione-bis-1,10- Phenanthroline (Ba (thd) ₂ (Phen) ₂ ) And Y (thd) ₂ And Cu (thd) ₂ Was used. Each of these was mixed at a molar ratio of Y: Ba: Cu = 1.0: 3.0: 2.7 and added to a solvent of tetrahydrofuran (THF) to a concentration of 7.0% by weight to oxidize. A liquid raw material (raw material solution) of the physical superconducting layer was used. Further, as a liquid raw material for the diffusion layer, Cu (thd) ₂ Prepared by adding 7.0% by weight to a THF solvent.
[0070]
In this example, the manufacturing apparatus shown in FIGS. 3 to 6 was used for manufacturing the oxide superconducting conductor. As a manufacturing method, Cu was first diffused into the surface layer portion of the base material using the liquid raw material for the diffusion layer. A method of forming an oxide superconductor by forming a diffusion layer and then forming an oxide superconductor on the diffusion layer using a liquid raw material of the oxide superconductor was adopted.
[0071]
[Diffusion layer deposition]
The raw material solution of the previous diffusion layer was continuously supplied to the raw material solution supply unit of the liquid raw material supply apparatus at a flow rate of 0.27 ml / min by a pressurized liquid pump (pressurization source). At the same time, Ar as a carrier gas was fed into the carrier gas supply unit at a flow rate of about 300 ccm. Through the above operation, a certain amount of mist-like liquid material is continuously supplied into the vaporizer, and further, a certain amount of the material gas evaporated from the liquid material is continuously supplied to the gas diffusion member of the CVD reactor through the gas introduction pipe. Supplied. The temperature of the vaporizer and the transport pipe at this time was 230 ° C.
[0072]
The substrate moving speed in the reactor of the substrate to be moved from the delivery drum side to the take-up drum side is 6.0 m / h, the substrate heating temperature is 700 ° C., and the reactor pressure is 5.0 Torr (5.0 × 133 Pa). Then, a Cu diffusion layer having a layer thickness of 200 nm was continuously formed on the surface layer of the substrate, and film formation was performed until the movement of the substrate having a predetermined length was completed. In addition, when Cu content of the base-material surface layer part in which this diffusion layer was formed was analyzed, 1 cm ² Per 100 to 200 μg.
[0073]
[Deposition of oxide superconducting layer]
Next, after the movement of the necessary length of the base material to be moved from the delivery drum side to the winding drum side was completed, the raw material solution of the diffusion layer was replaced with the raw material solution of the oxide superconducting layer. Then, the raw material solution of the oxide superconducting layer is continuously supplied to the raw material solution supply unit of the liquid raw material supply device by a pressurized liquid pump at a flow rate of 0.27 ml / min. At the same time, Ar is used as a carrier gas as a carrier gas. The gas was supplied to the gas supply unit at a flow rate of about 300 ccm. Through the above operation, a constant amount of mist-like liquid raw material is continuously supplied into the vaporizer, and the raw material gas vaporized from the liquid raw material is continuously supplied to the gas diffusion member of the CVD reactor through the gas introduction pipe. Supplied to. The temperature of the vaporizer and the transport pipe at this time was 230 ° C.
[0074]
Then, the substrate moving speed in the reactor of the substrate to be moved from the winding drum side to the feeding drum side by reversing the rotation direction of the feeding drum and the winding drum is 1.0 m / h, and the substrate heating temperature is 780. Set the temperature in the reactor to 5.0 Torr (5.0 × 133 Pa) and set the oxygen partial pressure value to 1.43 to 1.53 Torr (1.43 × 133 to 1.53 × 133 Pa). A YBaCuO-based oxide superconducting layer was continuously formed on the base material, and film formation was performed until the movement of the base material of a predetermined length was completed.
The oxide superconducting conductor provided with the diffusion layer was obtained by the above process. The manufacturing conditions for the oxide superconducting conductor of Example 1 are shown in Table 1 below.
[0075]
[Table 1]

[0076]
[Analysis / Evaluation]
Next, with respect to the two types of oxide superconducting conductors obtained above, the superconducting characteristics were evaluated using Sample A with the Ag foil thickness of 10 μm and Sample B with the Ag foil thickness of 50 μm. Went. The results are shown in Table 2. As shown in Table 2, when a base material in which an Ag foil is directly bonded to a metal base material without using a barrier layer is used, the oxide superconducting conductor of Sample A having an Ag foil thickness of 50 μm is Jc 130,000A / cm ² However, the oxide superconducting conductor of the sample A in which the thickness of the Ag foil is 10 μm has a Jc of 32,000 A / cm. ² Met. The difference in Jc is that when the thickness of the Ag foil is 10 μm, the diffused Hastelloy constituent elements (Ni, Cr, Mo, etc.) pass through the Ag foil and reach the oxide superconducting layer, so that the superconducting characteristics deteriorate. Conceivable.
[0077]
[Table 2]

[0078]
(Example 2)
Next, tape-like Hastelloy is used as a metal base material, and a Pt foil having a thickness of 5 μm is bonded to the metal base material as a barrier layer, and a {110} <110> texture having a thickness of 10 μm is formed on the Pt foil. An oxide superconducting conductor was prepared using a base material having a structure in which an Ag foil having a thickness of 2 was bonded. The synthesis conditions of the diffusion layer and the oxide superconducting layer other than the substrate were prepared in the same manner as in Sample A of Example 1 above. These conditions are shown in Table 3. In this example, the barrier layer is formed by bonding a Pt foil, but a layer made of Pt may be formed by sputtering or the like to form a barrier layer. Also, the Ag foil texture may be formed by applying heat treatment after the Ag foil is bonded.
[0079]
[Table 3]

[0080]
[Analysis / Evaluation]
The superconducting property was evaluated by using the oxide superconducting conductor prepared above as Sample C. The results are shown in Table 4. As shown in Table 4, the oxide superconducting conductor of Sample C in which a barrier layer is formed between the metal base material and the Ag foil has a Jc of 180,000 A / cm. ² It was confirmed that Jc was significantly improved as compared with Sample A of Example 1 above. This is considered to be due to the fact that the diffusion of hastelloy constituent elements is effectively suppressed by the barrier layer provided on the metal base material, and the oxide superconducting layer having good crystal orientation is formed on the Ag foil. It is done.
[0081]
[Table 4]

[0082]
【The invention's effect】
As described above in detail, according to the present invention, for an oxide superconducting conductor comprising a tape-shaped metal base material and an Ag layer having a rolling texture formed on at least one side of the metal base material. By comprising a base material, a diffusion layer formed by diffusing Cu in the surface layer portion of the Ag layer of the oxide superconducting conductor, and an oxide superconducting layer formed on the diffusion layer, An oxide superconductor having excellent strength and superconducting properties can be provided.
[0083]
Next, the base material for an oxide superconducting conductor of the present invention was provided with a tape-shaped metal base material and an Ag layer made of Ag having a rolling texture formed on at least one side of the metal base material. By being configured, it solves the problem of strength, which was a problem of conventional Ag base materials. In addition, since the technology for forming or bonding Ag on a metal base material can be applied to the technology used in the production of conventional clad materials, a high-strength base material can be obtained at low cost. An oxide superconductor can be manufactured without impairing the advantages of the Ag base material.
[0084]
Moreover, if the barrier layer is provided between the metal base material and the Ag layer, it is possible to suppress diffusion of elements constituting the metal base material into the Ag layer and the oxide superconducting layer. Therefore, the texture of the Ag layer and the crystal structure of the oxide superconducting layer can be kept good, and the crystal orientation and crystal continuity of the oxide superconducting layer formed on the Ag layer are improved. It is possible.
[0085]
Next, according to the method for producing an oxide superconducting conductor of the present invention, the base material of the present invention is used, and a diffusion layer in which Cu is diffused is formed in the surface layer portion of the Ag layer of the base material. Since the oxide superconducting layer is formed on the layer, diffusion of Cu from the oxide superconducting layer to the Ag base material is suppressed, and an oxide superconducting conductor excellent in superconducting characteristics can be easily manufactured. Therefore, according to the manufacturing method of the present invention, an oxide superconducting conductor having excellent superconducting characteristics and high strength can be manufactured at low cost.
[Brief description of the drawings]
FIG. 1 is a diagram showing a cross-sectional structure example of a base material for an oxide superconducting conductor according to the present invention, and FIG. 1 (A) is an example of a base material composed of a metal base material and an Ag foil. FIG. 1B shows an example in which a barrier layer is provided between a metal base material and an Ag foil.
2 is a diagram showing an example of a cross-sectional structure of an oxide superconducting conductor that can be produced by the method for producing an oxide superconducting conductor according to the present invention. FIG. 2 (A) is a diagram of FIG. An example using the base material having the configuration shown in A) is shown, and FIG. 2B shows an example using the base material having the configuration shown in FIG.
FIG. 3 is a diagram showing an overall configuration of an apparatus for manufacturing an oxide superconducting conductor according to the present invention.
4 is a configuration diagram showing a structural example of a raw material gas supply apparatus provided in the manufacturing apparatus shown in FIG. 3. FIG.
FIG. 5 is a perspective configuration diagram showing a structural example of a reactor provided in the manufacturing apparatus shown in FIG. 3;
6 is a cross-sectional configuration diagram showing an example of the structure of a reactor provided in the manufacturing apparatus shown in FIG. 3. FIG.
FIG. 7 is a cross-sectional view showing an example of a conventional oxide superconducting conductor.
FIG. 8 is a cross-sectional view showing another example of a conventional oxide superconducting conductor.
[Explanation of symbols]
S _A , S _B ... oxide superconducting conductor, a ... metal base material, b ... Ag foil (Ag layer), c ... diffusion layer, e ... barrier layer, 38, T, T _A , T _B ... base material, d ... oxide superconducting layer, A, B, C ... CVD unit, 30A ... CVD reactor, 31A ... reactor, 32A, 33A, 37A ... partition wall, 34A ... base material introduction part, 36A ... base material derivation 38A ... Boundary chamber 39A ... Base material passage hole 40 ... Gas diffusion part 53A ... Material gas introduction pipe 80A ... Gas exhaust means R ... Base material transport area

Claims (5)

  Cu was diffused in the surface layer portion of the Ag layer of the oxide superconducting conductor substrate comprising a tape-shaped metal base material and an Ag layer having a rolled texture formed on at least one side of the metal base material. A method for producing an oxide superconductor comprising: a step of forming a diffusion layer; and a step of forming an oxide superconducting layer by chemically reacting a raw material gas of the oxide superconductor on the diffusion layer . A reactor for performing a CVD reaction in which a raw material gas of an oxide superconducting conductor is chemically reacted on at least one surface side of a moving tape-like substrate to form an oxide superconducting thin film; A raw material gas supply means for supplying the oxide superconductor to be supplied; and a gas exhaust means for exhausting the gas in the reactor.
The raw material gas supply means for the oxide superconductor is provided with a raw material gas supply source for the oxide superconductor, a raw material gas introduction pipe for the oxide superconductor, and an oxygen gas supply means for supplying oxygen gas,
In the reactor, a base material introduction part, a reaction generation chamber, and a base material lead-out part are each partitioned via a partition, and a plurality of the reaction generation chambers are provided in series in the moving direction of the tape-shaped base material. A base material passing hole is formed in the reactor, and a base material conveyance region is formed in the reactor to pass through the base material introducing portion, the plurality of reaction generation chambers, and the base material outlet portion. Each has a gas diffusion part,
The plurality of reaction generation chambers are formed as film formation regions, and film formation is performed using a film formation apparatus in which the reaction gas generation unit is connected to the reaction gas generation chamber via the gas diffusion portion. The manufacturing method of the oxide superconducting conductor of Claim 1 characterized by the above-mentioned. The method for producing an oxide superconducting conductor according to claim 1 or 2, wherein the thickness of the Ag layer of the substrate is in the range of 10 µm to 100 µm . The method for producing an oxide superconducting conductor according to claim 1 , wherein a barrier layer is provided between the Ag layer of the base material and the metal base material . 5. The method for producing an oxide superconductor according to claim 4, wherein the thickness of the Ag layer of the base material is 5 μm or more and 10 μm or less .

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