JP5459132B2 - Method of manufacturing an oxide superconducting bulk material - Google Patents

Method of manufacturing an oxide superconducting bulk material Download PDF

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JP5459132B2
JP5459132B2 JP2010171076A JP2010171076A JP5459132B2 JP 5459132 B2 JP5459132 B2 JP 5459132B2 JP 2010171076 A JP2010171076 A JP 2010171076A JP 2010171076 A JP2010171076 A JP 2010171076A JP 5459132 B2 JP5459132 B2 JP 5459132B2
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英一 手嶋
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新日鐵住金株式会社
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Description

本発明は、酸化物超電導バルク材料の製造方法に関する。 The present invention relates to a method for producing an oxide superconductive bulk material.

RE−Ba−Cu−O(REはY又は希土類元素から選ばれる1種又は2種以上の元素)の組成からなる希土類系酸化物超電導材料は、超強力なマグネットや磁気浮上等の応用に有望視されているが、その特性を引き出すためには、材料の微細な組織制御が重要である。 RE-Ba-Cu-O (RE is one or more elements selected from Y or a rare earth element) rare earth oxide superconducting material having a composition of, promising applications such super-strong magnets and magnetic levitation It has been seen, in order to bring out the characteristics of a fine structure control of the material is important. 例えば、特許文献1には、高特性化するために、単結晶状のREBa 2 Cu 3y中にRE 2 BaCuO 5が微細分散した酸化物超電導バルク材料が開示されている。 For example, Patent Document 1, in order to highly characterized, oxide superconducting bulk material RE 2 BaCuO 5 is finely dispersed in the REBa 2 Cu 3 O y of the single crystal form is disclosed. このような高特性を有する酸化物超電導バルク材料は、一般的には溶融法により作製される。 Oxide superconductive bulk material having such high characteristics, are generally made by the melting method. 溶融法では、大気中にて成形体を溶融状態まで加熱し、その後徐冷中に結晶成長させることによって酸化物超電導バルク材料を作製する。 In the melt method, the molded body was heated to a molten state in air, forming the oxide superconductive bulk material by subsequent crystal growth during annealing.

また、希土類系酸化物超電導材料の超電導特性は酸素量に大きく依存するが、結晶成長後の酸化物超電導バルク材料は酸素量が不足した状態にある。 Furthermore, the superconducting properties of the rare earth oxide superconducting material depends largely on the amount of oxygen, the oxide superconductive bulk material after the crystal growth is in the state of oxygen amount is insufficient. そこで、材料中の酸素量を増加させるために酸素富化過程を導入する必要がある。 Therefore, it is necessary to introduce the oxygen-enriched process in order to increase the oxygen content in the material. 例えば、特許文献2には、結晶成長後に試料を所定の形状に加工してから酸素富化処理を行うことが開示されている。 For example, Patent Document 2, by performing the oxygen enrichment process is disclosed a sample after the crystal growth from the machined into a predetermined shape. さらに、酸素富化過程の実施例としては、酸素雰囲気中で500℃〜400℃の温度領域を100時間程度熱処理することが示されている。 Furthermore, as the embodiment of the oxygen-enriched process, it has been shown that a heat treatment of about 100 hours the temperature region in an oxygen atmosphere 500 ° C. to 400 ° C..

特公平4−40289号公報 Kokoku 4-40289 Patent Publication No. 特許第3889822号公報 Patent No. 3889822 Publication

上述したように、希土類系酸化物超電導バルク材料においては、結晶成長後に超電導特性を付与するために酸素富化過程が必要となる。 As described above, in the rare earth-based oxide superconducting bulk material, oxygen enrichment process is needed to impart superconductivity after the crystal growth. しかしながら、酸素富化過程で酸素を十分に富化させた材料でも、本来得られるべき高い超電導特性が得られていないという問題があった。 However, oxygen-enriched oxygen is also a material was sufficiently enriched in the process, there is a problem that no high superconducting properties to be obtained originally obtained. その理由としては、結晶成長直後の酸化物超電導バルク材料の結晶構造には、乱れや歪、構成原子間の置換が存在しているからであり、本来得られるべき超電導特性よりも低くなっている。 The reason is that the crystal structure of the oxide superconductive bulk material immediately after crystal growth, is because disturbance or distortion, substitution between component atoms are present, it is lower than the superconducting properties to be obtained originally . このように従来の酸素富化過程では、試料中に酸素を十分に富化させることはできても、結晶成長直後の酸化物超電導バルク材料に存在する結晶構造の乱れや歪等を回復させることはできなかった。 In this way, conventional oxygen enrichment process, although it is possible to sufficiently enrich the oxygen in the sample, to restore the disturbance or distortion or the like of the crystal structure present in the oxide superconductive bulk material immediately after crystal growth could not.

そこで、本発明では、上記の問題を解決し、酸素富化過程を含む酸化物超電導バルク材料の製造方法において、十分に高い超電導特性を得ることのできる酸化物超電導バルク材料の製造方法を提供することを目的とする。 Therefore, in the present invention to solve the above problems, in the method of manufacturing an oxide superconducting bulk material comprising oxygen enrichment process, to provide a method of manufacturing an oxide superconducting bulk material capable of obtaining a sufficiently high superconductivity and an object thereof.

本発明の酸化物超電導バルク材料の製造方法は、以下のとおりである。 Method of manufacturing an oxide superconducting bulk material of the present invention is as follows.
(1) 単結晶状のRE 1+x Ba 2-x Cu 3y (REはY又は希土類元素から選ばれる1種又は2種以上の元素、−0.1≦x≦0.1、6.8≦y≦7.2)中にRE 2 BaCuO 5が微細分散した酸化物超電導バルク材料の製造方法であって、溶融状態から徐冷中に結晶成長させた酸化物超電導バルク材料の酸素量を酸素富化過程において富化する前に、 酸素分圧が0.00001気圧以上0.05気圧以下、 1000K以上、1250K以下の温度で前記結晶成長させた酸化物超電導バルク材料を熱処理する酸素富化前熱処理過程を有することを特徴とする酸化物超電導バルク材料の製造方法。 (1) single crystalline RE 1 + x Ba 2-x Cu 3 O y (RE is one or more elements selected from Y or a rare earth element, -0.1 ≦ x ≦ 0.1,6 .8 ≦ y ≦ 7.2) is RE 2 BaCuO 5 in the method of manufacturing a finely dispersed oxide superconductive bulk material, the oxygen the oxygen content of the oxide superconductive bulk material obtained by crystal growth during the slow cooling from the molten state before enriched in enrichment process, the oxygen partial pressure of 0.00001 atm to 0.05 atm or less, more 1000 K, before oxygen enrichment of heat treating an oxide superconducting bulk material obtained by the crystal growth at a temperature of 1250K method of manufacturing an oxide superconducting bulk material characterized by having a heat treatment process.
(2)前記酸素富化前熱処理過程後の酸化物超電導バルク材料の質量に対する前記酸素富化過程後の酸化物超電導バルク材料の質量の増分割合が、1mass%以上、1.5mass%以下であることを特徴とする(1)に記載の酸化物超電導バルク材料の製造方法。 (2) increment ratio of the mass of the oxide superconductive bulk material after said oxygen-enriched prior to heat treatment process wherein the oxygen-enriched process to the mass of the oxide superconductive bulk material later, 1 mass% or more, or less 1.5 mass% method of manufacturing an oxide superconducting bulk material according to (1), wherein a.
(3)前記酸化物超電導バルク材料のRE元素が、La、Nd、Sm、Eu、Gd、Dyから選ばれる1種又は2種以上を含むことを特徴とする(1) 又は(2)に記載の酸化物超電導バルク材料の製造方法。 (3) RE element of the oxide superconductive bulk material, La, Nd, Sm, Eu , Gd, according to, characterized in that it comprises one or more selected from Dy (1) or (2) method of manufacturing an oxide superconducting bulk material.

本発明により、酸素富化過程を含む酸化物超電導バルク材料の製造方法において、十分に高い超電導特性を得ることのできる酸化物超電導バルク材料の製造方法を提供することができる。 The present invention, in the method of manufacturing an oxide superconducting bulk material comprising oxygen enrichment process can provide a method of manufacturing an oxide superconducting bulk material capable of obtaining a sufficiently high superconductivity.

本発明の実施形態に係る酸化物超電導バルク材料の製造方法の一例を示す概念図である。 It is a conceptual diagram showing an example of a method of manufacturing an oxide superconductive bulk material according to the embodiment of the present invention. 従来の酸化物超電導バルク材料の製造方法を示す概念図である。 It is a conceptual diagram illustrating a conventional method of manufacturing an oxide superconducting bulk material. 本発明の実施形態に係る酸化物超電導バルク材料の製造方法の別の態様を示す概念図である。 It is a conceptual diagram showing another embodiment of a manufacturing method for the oxide superconductive bulk material according to the embodiment of the present invention. 本発明の実施例における酸化物超電導バルク材料の捕捉磁場分布の測定結果を示す図である。 Is a graph showing measurement results of the trapped magnetic field distribution of the oxide superconductive bulk material in the embodiment of the present invention.

以下に、本発明の実施形態について図に沿って説明する。 Hereinafter, it will be explained with reference to FIG. Embodiments of the present invention.
図1は、本実施形態における酸化物超電導バルク材料の製造方法の一例を示す概念図であり、図2は、従来の酸化物超電導バルク材料の製造方法を示す概念図である。 Figure 1 is a conceptual diagram showing an example of a method of manufacturing an oxide superconductive bulk material in the present embodiment, FIG. 2 is a conceptual diagram illustrating a conventional method of manufacturing an oxide superconducting bulk material.
酸化物超電導バルク材料は、成形体を溶融状態になるまで加熱し、溶融状態から徐冷中に結晶成長させることにより製造される。 Oxide superconducting bulk material is heated until the compact in a molten state, is produced by crystal growth during the slow cooling from the molten state. 酸化物超電導バルク材料の超電導特性は酸素量に依存するが、結晶成長直後の試料は酸素量が不足しているため、超電導特性を付与するために酸素富化過程が必要となる。 While superconducting properties of the oxide superconducting bulk material is dependent on the oxygen content, a sample immediately after the crystal growth because the amount of oxygen is insufficient, oxygen enrichment process is needed to impart superconductivity. 従来は、図2に示すように、結晶成長したものを必要に応じて所定の形状に加工した後に酸素富化処理を行っていたが、本実施形態では、図1に示すように、結晶成長したものを必要に応じて所定の形状に加工した後であって、酸素富化過程の前に酸素富化前熱処理過程を設けていることを特徴としている。 Conventionally, as shown in FIG. 2, but as necessary that crystal growth has been performed oxygen enrichment process after processing into a predetermined shape, in the present embodiment, as shown in FIG. 1, the crystal growth the optionally ones even after processed into a predetermined shape, is characterized in that is provided with the oxygen-enriched before the heat treatment process prior to oxygen enrichment process.

酸素富化過程では、酸素分圧0.2気圧以上の雰囲気にて、600K〜800Kの温度で数十〜数百時間の熱処理を行うことにより、酸化物超電導バルク材料中に酸素を付与する。 The oxygen-enriched process at an oxygen partial pressure of 0.2 atm or more atmosphere, heat treatment is performed at several tens to several hundreds of hours at a temperature of 600K~800K, provides oxygen in the oxide superconductive bulk material. 一方、酸素富化前熱処理過程では、酸素富化過程よりも十分に高い温度、即ち、1000K以上、1250K以下の温度で熱処理を行う。 On the other hand, in the oxygen-enriched before the heat treatment process, the oxygen-enriched sufficiently higher temperature than the process, i.e., more than 1000 K, the heat treatment is performed at temperatures below 1250K.

本発明者らが鋭意調査した結果、結晶成長直後の酸化物超電導バルク材料の結晶構造には乱れや歪、構成原子間の置換が存在しているために、本来得られるべき超電導特性よりも低くなっていることが明らかになった。 The present inventors have made extensive research, disturbance or distortion in the crystal structure of the oxide superconductive bulk material immediately after crystal growth, for the substitution between constituent atoms are present, lower than superconducting properties should originally obtained it is that has been revealed. 従来の酸素富化過程では、試料中に酸素を十分に富化させることはできても、結晶成長直後の酸化物超電導バルク材料に存在する結晶構造の乱れや歪等を回復させることはできなかった。 In conventional oxygen enrichment process, although it is possible to sufficiently enrich the oxygen in the sample, not possible to recover the disturbance or distortion or the like of the crystal structure present in the oxide superconductive bulk material immediately after crystal growth It was. そのため、ミクロ的にはきれいな結晶構造であったとしても、試料全体のマクロ的な視点においては結晶性が低下し、その結果、十分高い超電導特性が得られていなかった。 Therefore, even a clean crystal structure microscopically, in the macro viewpoint of the whole sample was reduced crystallinity, resulting in sufficiently high superconducting properties were not obtained.

そこで、本発明では、酸素富化過程の前に酸素富化過程よりも十分に高い温度で高温熱処理を行う。 Therefore, in the present invention performs high-temperature heat treatment at a sufficiently higher temperature than the oxygen enrichment process prior to oxygen enrichment process. これにより、酸化物超電導バルク材料を構成している原子の再配列が起こり、試料全体のマクロ的な視点での結晶性が向上し、その結果、超電導特性が改善する。 Accordingly, it occurs rearrangement of atoms constituting the oxide superconductive bulk material, improves the crystallinity of a macro viewpoint of the whole sample, as a result, superconducting characteristics are improved. 原子の再配列が起こるためには温度が高い方が好ましいが、温度を上げ過ぎると酸化物超電導バルク材料が再溶融するので、酸素富化前熱処理過程の最高温度は1000K以上、1250K以下である必要がある。 Although for rearrangement of atoms occurs it is preferable temperature is high, since the oxide superconductive bulk material and excessively high temperatures can be remelted, the maximum temperature of the oxygen-enriched prior to heat treatment process above 1000 K, are the following 1250K There is a need. なお、原子を再配列する時間を短縮する点と材料の再溶融を防止する点とから、酸素富化前熱処理過程の最高温度を1100K以上、1200K以下にすることがより好ましい。 Incidentally, from the viewpoint of preventing the re-melting point and the material to shorten the time to rearrange the atoms, the maximum temperature of the oxygen-enriched prior to heat treatment process 1100K or more, and more preferably below 1200 K.

酸素富化前熱処理過程での原子の再配列は、余分な酸素原子がない方が起こり易い。 Rearrangement of atoms in the oxygen-enriched before the heat treatment process is likely to occur is better no extra oxygen atom. したがって、酸素富化前熱処理過程での雰囲気は、結晶成長時の雰囲気である大気圧よりも小さい酸素分圧、すなわち0.2気圧よりも小さい酸素分圧にする必要がある。 Therefore, the atmosphere in the oxygen-enriched before the heat treatment process is less oxygen partial pressure than the atmospheric pressure which is the atmosphere during crystal growth, i.e. there must be a small oxygen partial pressure than 0.2 atm. なお、酸素分圧が0.05気圧以下になると、さらにRE原子とBa原子との置換が起こり難くなるので、酸素分圧は0.05気圧以下することがより好ましい。 Incidentally, if the oxygen partial pressure is below 0.05 atm, since more difficult to occur substitution of RE atoms and Ba atoms, the oxygen partial pressure is more preferably to below 0.05 atm. 酸素分圧は小さい方が好ましいが、油回転ポンプによるガス置換で容易に実現できる酸素分圧として0.00001気圧まで低下させれば十分である。 Oxygen partial pressure is preferably small, but it is sufficient reduced to 0.00001 atm as an oxygen partial pressure that can be easily realized by the gas replacement by an oil rotary pump.

また、酸素富化前熱処理過程では、固体中の原子を拡散させて原子を再配列するため、多くの時間がかかる。 Moreover, in the oxygen-enriched before heat treatment process, since the atoms in the solid is diffused rearranging atoms, more time-consuming. そこで、1000K以上の保持時間を10時間以上にすることが好ましい。 Therefore, it is preferable that the above holding time 1000K than 10 hours. 原子を再配列する観点からは保持時間は長くてもよいが、酸化物超電導材料の生産性が低下する観点からは、200時間以下にした方が好ましい。 Retention time from the viewpoint of rearranged atom may be longer, but from the viewpoint of productivity of the oxide superconducting material is lowered, it is preferable that the following 200 hours.

さらに、酸素富化前熱処理過程では、酸素富化過程よりも高い温度まで昇温するので、数mm程度の材料であれば特に問題にならないが、10mm以上の大きな材料の場合、材料の外部と中心部とに大きな温度差が生じるため、材料内の熱応力が大きくなり、熱処理中に材料が割れる可能性がある。 Moreover, in the oxygen-enriched before the heat treatment process, since the temperature is raised to a temperature higher than the oxygen-enriched process, although not a particular problem as long as the material of about several mm, for large material above 10 mm, and the outside of the material since a large temperature difference and the central portion occurs, the thermal stress increases in the material, there is a possibility that the material to crack during heat treatment. 10mm以上の大きな材料の場合、酸素富化前熱処理過程で材料が割れることを防止するために、昇温速度及び降温速度は40K/時間以下にすることが好ましい。 For large material above 10 mm, in order to prevent the material in oxygen-enriched before the heat treatment process is cracked, heating rate and cooling rate it is preferably set to below 40K / time.

酸素富化前熱処理過程及び酸素富化過程は、別々であってもよいし、図3に示すように、連続であってもよい。 Enriched before the thermal treatment process and oxygen-enriched process, it may be separate, as shown in FIG. 3, may be continuous. 連続である場合には全体としての工程時間を短縮でき、生産性の観点からは好ましい。 If it is continuous it can shorten the process time as a whole, preferable from the viewpoint of productivity. 酸素富化前熱処理と酸素富化処理とを連続して行う場合、熱処理中の雰囲気を低酸素分圧から高酸素分圧に切り換える必要がある。 When performing the oxygen enrichment before the heat treatment and oxygen enrichment process continuously, it is necessary to switch the atmosphere during the heat treatment from a low oxygen partial pressure in the high oxygen partial pressure. このとき、急激に酸素が富化しないように、高酸素分圧への切り換えは800K以下の温度で行った方が好ましい。 At this time, as rapidly oxygen is not enriched, switching to the high oxygen partial pressure is preferably person who conducted at temperatures below 800 K. 酸素富化過程では、酸化物超電導バルク材料中に酸素を付与するため、酸素分圧0.2気圧以上の雰囲気にて、600K〜800Kの温度で数十〜数百時間の熱処理を行うことが好ましい。 The oxygen-enriched process for imparting oxygen in the oxide superconductive bulk material at an oxygen partial pressure of 0.2 atm or more atmosphere, be subjected to heat treatment several tens to several hundreds of hours at temperatures of 600K~800K preferable.

酸素富化前熱処理過程後における酸化物超電導バルク材料の質量に対する酸素富化過程後における酸化物超電導バルク材料の質量の増分割合は、超電導特性を付与するために酸素量の増分が多くなることが好ましい。 Weight increment rate of the oxide superconductive bulk material after the oxygen enrichment process to the mass of the oxide superconductive bulk material after the oxygen-enriched prior to heat treatment process, that the amount of oxygen incremental increases to impart superconductivity preferable. 即ち、1mass%以上であることが好ましい。 That is, it is preferably at least 1 mass%. 一方、この増分割合が大き過ぎると、過剰酸素によって逆に超電導特性が低下する恐れがあるので、質量増分は1.5mass%以下であることが好ましい。 On the other hand, if the increment ratio is too large, the superconducting properties conversely by the excess oxygen may be lowered, it is preferred weight increment is less 1.5 mass%.

結晶成長後に酸化物超電導バルク材料の結晶構造が乱れる原因の1つに、RE原子とBa原子との置換がある。 One of the causes of the crystal structure of the oxide superconductive bulk material after the crystal growth is disturbed, substituted with RE atoms and Ba atoms. この場合、酸化物超電導バルク材料の超電導相の化学式は、RE 1+x Ba 2-x Cu 3yとなる。 In this case, the chemical formula of the superconducting phase of the oxide superconductive bulk material, the RE 1 + x Ba 2-x Cu 3 O y. このRE原子とBa原子との置換は、大気中で結晶成長させると起り易く、さらにRE元素の中でイオン半径が比較的大きい、La、Nd、Sm、Eu、Gd、Dyで起り易い。 Substitution between the RE atoms and Ba atoms are liable to occur and the crystal growth in the air, is relatively large further ionic radius in the RE element, La, Nd, Sm, Eu, Gd, occur in Dy easily. したがって、本発明による酸素富化過程前に酸素富化前熱処理過程を設けた製造方法の効果が顕著に現れる。 Therefore, the effect of the manufacturing method before oxygen enrichment process according to the invention provided with oxygen-enriched before the heat treatment process becomes conspicuous. したがって、本発明に用いられる酸化物超電導バルク材料としては、REがLa、Nd、Sm、Eu、Gd、及びDyから選ばれる1種又は2種以上であることが好ましい。 Therefore, as the oxide superconductive bulk material used in the present invention, RE is La, Nd, Sm, Eu, Gd, and is preferably one or more selected from Dy.

また、このRE原子とBa原子との置換は、低酸素雰囲気中で結晶成長させることによって抑制できることが知られているが、高価な雰囲気制御用の結晶成長炉が必要であり、さらに雰囲気制御用結晶成長炉では大気炉に比べて量産性に劣る。 Further, substitution with the RE atoms and Ba atoms, although known to be inhibited by crystal growth in a low oxygen atmosphere, it is necessary crystal growth furnace expensive atmosphere control, for more controlled atmosphere crystal inferior to mass production as compared to the atmosphere furnace in the growth furnace. しかし、本発明の酸素富化前熱処理過程では、結晶成長させる必要はないので、一度に大量の材料を熱処理することが可能であり、量産性にも優れている製造方法である。 However, the oxygen-enriched before the heat treatment process of the present invention, there is no need to be grown, it is possible to heat treatment a large amount of material at a time, a manufacturing method is excellent in mass productivity. RE原子とBa原子との置換が大きくなると、超電導特性が大きく低下するので、置換量xは、−0.1≦x≦0.1の範囲とする。 When substitution of RE atoms and Ba atoms increases, the superconducting properties is greatly reduced, the substitution amount x is in the range of -0.1 ≦ x ≦ 0.1. また、化学量論組成での酸素量y=7.0から大きくずれると、超電導性発現に必要なキャリア密度が低下し、その結果、超電導特性が大きく低下する。 Further, it deviates significantly from the oxygen amount y = 7.0 in the stoichiometric composition, the carrier density required for superconductivity expression is decreased, as a result, superconducting characteristics are deteriorated greatly. そのため、酸素量yは、6.8≦y≦7.2の範囲とする。 Therefore, the oxygen amount y is in the range of 6.8 ≦ y ≦ 7.2.

(実施例1) (Example 1)
本実施例で使用した酸化物超電導バルク材料の製造方法について述べる。 The process for producing an oxide superconductive bulk material used in this embodiment. まず、市販されている純度99.9質量%の希土類元素(RE)、バリウム(Ba)、銅(Cu)の酸化物の粉末を、RE:Ba:Cu=1.6:2.3:3.3のモル比で秤量し、それに白金を0.5質量%加えた。 First, purity of 99.9 wt% of rare earth elements, which is commercially available (RE), barium (Ba), a powder of oxide of copper (Cu), RE: Ba: Cu = 1.6: 2.3: 3 were weighed in a molar ratio of .3, it was added 0.5 wt% of platinum. RE元素としては、Nd、Sm、Eu、Gd、Dy、Y、Ho、Erを用い、そのうち、Nd、Sm、Eu、Gdについては、銀を10質量%加えた。 The RE element, using Nd, Sm, Eu, Gd, Dy, Y, Ho, and Er, of which, Nd, Sm, Eu, for Gd was added silver 10% by mass. この秤量粉を2時間かけて十分混練してから、大気中にて1173Kで8時間仮焼した。 This weighed powder from fully kneaded over a period of 2 hours, 8 hours and calcined at 1173K in the atmosphere.

次に、金型を用いて仮焼粉を円板形状に成形した。 It was then molded calcined powder into a disk shape using a mold. この成形体を1373Kまで加熱して溶融状態にし、30分間保持した後、降温途中で種付けを行い、1278K〜1252Kの温度領域を100時間かけて徐冷し結晶成長させた。 The molded body was heated up to 1373K to a molten state, after holding for 30 minutes, subjected to seeding on the way cooling, grown crystal was gradually cooled over a period of 100 hours the temperature region of 1278K~1252K. 上述した製造方法で作製した試料は、単結晶状のRE 1+x Ba 2-x Cu 3y中にRE 2 BaCuO 5が微細分散した組織を有しておりRE 2 BaCuO 5の大きさは平均1〜2μmであった。 Samples prepared by the above-described manufacturing method, the size of the RE 2 BaCuO 5 RE 2 BaCuO 5 in the single crystalline RE 1 + x Ba 2-x Cu 3 O y has a finely dispersed tissue with an average of 1~2μm. 結晶成長直後の試料の大きさは、直径48mm、高さ20mm程度であったが、乾式加工により、直径46mm、高さ15mmに加工した。 The size of the sample immediately after crystal growth, diameter 48 mm, was the height 20mm approximately, by dry processing, and processed diameter 46 mm, a height 15 mm. なお、銀を10質量%加えたNd、Sm、Eu、Gdについては、数μm〜数十μmの銀粒子が微細に分散した組織を有していた。 Incidentally, Nd silver plus 10 wt%, Sm, Eu, for Gd is several μm~ several tens μm silver particles had a finely dispersed organizations.

次に、この加工体を酸素富化前熱処理過程として、酸素分圧0.01気圧下、1150Kで100時間熱処理した。 Then, the workpiece as the oxygen enriched before the heat treatment process, an oxygen partial pressure of 0.01 atm, and heat treated for 100 hours at 1150K. なお、この時の昇温速度及び降温速度は20K/時間とした。 The heating rate and cooling rate at this time was set to 20K / time. その後、酸素富化過程として、酸素雰囲気中で723K〜673Kの温度領域を100時間程度熱処理した。 Thereafter, the oxygen-enriched process was heat treated about 100 hours the temperature region of 723K~673K in an oxygen atmosphere.

本実施例の試料(以下、本実施例材)における超電導特性を調べるため、超電導マグネットを用いて試料に磁場を捕捉させ、液体窒素中での捕捉磁場分布をホール素子にて測定した。 Samples of this embodiment (hereinafter, this embodiment material) To investigate the superconducting properties of the sample in to capture the magnetic field by using a superconducting magnet was measured trapped magnetic field distribution in the liquid nitrogen in the hall element. 図4に測定した磁場分布の例を示す。 An example of a magnetic field distribution measured in FIG. 捕捉磁場分布がきれいな同心円状をしていることから、結晶成長が良好であったことが分かる。 Since the trapped magnetic field distribution is a clean concentric, it is understood that the crystal growth was good. 比較のため、酸素富化前熱処理過程を省略した以外は本実施例と同様にして製造した比較材についても、同じ条件にて捕捉磁場分布を測定した。 For comparison, except for omitting the oxygen-enriched before the heat treatment process for also compares material manufactured in the same manner as this example was measured trapped magnetic field distribution under the same conditions. 測定の結果、比較材の捕捉磁場分布も同様に同心円状であった。 As a result of the measurement, it was equally concentric also trapped magnetic field distribution of the comparative material.

以下の表1に、本実施例材及び比較材の捕捉磁場のピーク値を示す。 Table 1 below shows the peak values ​​of the trapped magnetic field in this embodiment material and comparative material.

表1に示すように、本実施例材と比較材とを比べると、本実施例材は20%程度捕捉磁場のピーク値が改善していることが分かる。 As shown in Table 1, compared with the comparative material with this embodiment material, this embodiment material it is found that improved peak value of the trapped magnetic field by about 20%. つまり、本実施例材は、超電導特性の改善に効果があるものであると言える。 That is, the present embodiment material can be said to be those which are effective in improving the superconducting property. なお、本実施例材について、電子線マイクロアナライザーにより組成を分析すると、RE元素のBa元素置換量xは、x=−0.01〜+0.02であることが確認できた。 Note that this embodiment material, the analysis of the composition by electron beam microanalyzer, Ba element substitution amount x of RE elements were confirmed to be x = -0.01 + 0.02. さらに、酸素富化過程後の酸素量yをヨードメトリーにより分析すると、酸素量yは、y=6.9〜7.0であることが確認できた。 Further, when the oxygen amount y after oxygen enrichment process is analyzed by iodometry, oxygen amount y was confirmed to be y = from 6.9 to 7.0.

(実施例2) (Example 2)
RE元素として、Gd:Dy=9:1で秤量した以外は実施例1と同様の製造方法により、直径46mm、高さ15mmの加工体を製造した。 As RE elements, Gd: Dy = 9: the same manufacturing method as in Example 1, except that the weighed at 1, to produce a diameter 46 mm, processing of height 15 mm. 次に、この加工体を酸素富化前熱処理過程として、酸素分圧0.05気圧下、1200Kで30時間熱処理した。 Then, as the workpiece oxygen enrichment before the heat treatment process, an oxygen partial pressure of 0.05 atm, was heat-treated at 1200 K 30 hours. なお、この時の昇温速度及び降温速度は40K/時間とした。 The heating rate and cooling rate at this time was set to 40K / time. その後、酸素富化過程として、酸素雰囲気中で723K〜673Kの温度領域を100時間程度熱処理した。 Thereafter, the oxygen-enriched process was heat treated about 100 hours the temperature region of 723K~673K in an oxygen atmosphere. 得られた超電導体の組織は、実施例1と同様に、単結晶状の(Gd 0.9 Dy 0.11+x Ba 2-x Cu 3y中に(Gd 0.9 Dy 0.12 BaCuO 5と銀粒子が微細分散した組織を有しており、(Gd 0.9 Dy 0.12 BaCuO 5の大きさは平均1〜2μmで、銀粒子の大きさは平均50μmであった。 The resulting superconductor tissue, in the same manner as in Example 1, the single crystalline (Gd 0.9 Dy 0.1) 1 + x Ba 2-x Cu 3 in O y (Gd 0.9 Dy 0.1) 2 BaCuO 5 and silver particles have a finely dispersed tissue, the size of (Gd 0.9 Dy 0.1) 2 BaCuO 5 on average 1 to 2 [mu] m, the size of the silver particles had an average 50 [mu] m. また、RE元素のBa元素置換量xは、x=+0.005で、酸素量yは、y=6.94であった。 Moreover, Ba element substitution amount x of RE elements, at x = + 0.005, the oxygen amount y was y = 6.94. 比較のため、酸素富化前熱処理過程を省略した以外は本実施例と同じ条件にて比較材を製造した。 For comparison, except for omitting the oxygen-enriched before the heat treatment process to produce a comparative material under the same conditions as the embodiment.

捕捉磁場のピーク値を測定したところ、本実施例材の液体窒素中の捕捉磁場のピーク値は1.8Tであり、比較材のピーク値1.44Tに比べて25%改善していることが確認できた。 The measured peak values ​​of the trapped magnetic field, the peak value of the trapped magnetic field in liquid nitrogen in this embodiment material is 1.8 T, that has improved by 25% as compared with the peak value 1.44T comparison material It could be confirmed. さらに、冷凍機を用いて65Kでの捕捉磁場のピーク値を比較したところ、本実施例材で4T、比較材で2.9Tとなり、38%改善した。 Furthermore, when comparing the peak values ​​of the trapped magnetic field at 65K using a refrigerator, 4T in this embodiment material, 2.9T next comparison material was improved 38%. このことから、改善度合いは低温ほど大きいことが分かった。 Therefore, degree of improvement was found to be greater at lower temperatures. つまり、本実施例材は、低温での超電導特性の改善により効果があるものであると言える。 That is, the present embodiment material can be said to be those which are effective by improving the superconducting properties at low temperatures.

(実施例3) (Example 3)
RE元素としてDyを用いた以外は実施例1と同様の製造方法により、直径46mm、高さ15mmの加工体を製造した。 By the same production method as in Example 1 except for using Dy as the RE element, to produce a diameter 46 mm, processing of height 15 mm. 次に、この加工体を酸素富化前熱処理過程として、酸素分圧0.02気圧下、昇温速度20K/時間にて1100Kで150時間熱処理した。 Then, as the workpiece oxygen enrichment before the heat treatment process, an oxygen partial pressure of 0.02 atm, and 150 hours heat treatment at 1100K at heating rate 20K / time. その後、降温速度20K/時間で723Kまで降温した。 Then, the temperature was lowered to 723K at a cooling rate of 20K / time. 723Kに保持した状態で、酸素分圧を0.02気圧から1気圧へ50時間かけて変化させた後、酸素富化過程として、723K〜673Kの温度領域を100時間程度熱処理した。 While holding the 723K, after the oxygen partial pressure is varied over a 50-hour to 1 atm 0.02 atm, as an oxygen-enriched process was heat treated about 100 hours the temperature region of 723K~673K. 得られた超電導体の組織は、実施例1と同様に、単結晶状のDy 1+x Ba 2-x Cu 3y中にDy 2 BaCuO 5が微細分散した組織を有しており、Dy 2 BaCuO 5の大きさは平均1〜2μmであった。 The resulting superconductor tissue, in the same manner as in Example 1, Dy 2 BaCuO 5 are a finely dispersed organizations in the single crystalline Dy 1 + x Ba 2-x Cu 3 O y, Dy size of 2 BaCuO 5 averaged 1 to 2 [mu] m. また、RE元素のBa元素置換量xは、x=+0.01で、酸素量yは、y=6.92であった。 Moreover, Ba element substitution amount x of RE elements, at x = + 0.01, the oxygen amount y was y = 6.92. 比較のため、酸素富化前熱処理過程を省略した以外は本実施例と同じ条件にて比較材Aを製造した。 For comparison, except for omitting the oxygen-enriched before the heat treatment process to produce a comparative material A under the same conditions as the embodiment. さらに、酸素富化前熱処理過程以外では本実施例と同じ条件にて製造したものであって、酸素富化前熱処理過程として、酸素分圧0.02気圧下、900Kで150時間熱処理した比較材B、及び酸素富化前熱処理過程として、酸素分圧0.02気圧下、1300Kで150時間熱処理した比較材Cを製造した。 Moreover, except in the oxygen-enriched prior to heat treatment process be those produced under the same conditions as the embodiment, as an oxygen-enriched before the heat treatment process, an oxygen partial pressure of 0.02 atm, the comparative material was 150 hours heat treatment at 900K B, and the oxygen-enriched before the heat treatment process, an oxygen partial pressure of 0.02 atm, was prepared comparative material C was heat-treated at 1300K 0.99 hours.

捕捉磁場のピーク値を測定したところ、本実施例材の液体窒素中の捕捉磁場のピーク値は1.05Tであり、比較材Aのピーク値0.85Tに比べて20%以上改善していることが確認できた。 The measured peak values ​​of the trapped magnetic field, the peak value of the trapped magnetic field in liquid nitrogen in this embodiment material is 1.05T, is improved 20% or more as compared with the peak value 0.85T comparison material A it was confirmed. また、比較材Bの捕捉磁場のピーク値は0.83Tであり、比較材Aと同程度であった。 The peak value of the trapped magnetic field of the comparative material B is 0.83T, it was comparable to comparative material A. さらに、比較材Cでは、試料の一部が溶融した後に固化したため、試料形状が円板状を留めていないだけでなく、捕捉磁場のピーク値は0.01Tで非常に小さくなった。 In Comparative material C, because a part of the sample was solidified after melting, not only the sample shape is not fastened to disk-shaped, the peak value of the trapped magnetic field was very small at 0.01 T. 以上の結果から、本実施例材のように、酸素富化前熱処理過程と酸素富化過程とを連続して行っても超電導特性の改善に効果があると言える。 These results, as in this embodiment material, also an oxygen-enriched before the heat treatment process and oxygen-enriched process performed continuously said to be effective in improving the superconducting property. また、酸素富化前熱処理過程として、本発明の範囲外の温度で熱処理を実施しても、超電導特性の改善が認められないことが確認できた。 Further, as an oxygen-enriched before the heat treatment process, even when heat treatment is performed at a temperature outside the range of the present invention, it was confirmed that the improvement of the superconducting properties is not observed.

本発明によれば、酸素富化過程を含む酸化物超電導バルク材料の製造方法であって、十分に高い超電導特性を得ることのできる酸化物超電導バルク材料の製造方法を提供することができるので、酸化物超電導バルク材料の工業上の利用範囲が拡大する。 According to the present invention, there is provided a method of manufacturing an oxide superconducting bulk material comprising oxygen enrichment process, it is possible to provide a method of manufacturing an oxide superconducting bulk material capable of obtaining a sufficiently high superconductivity, industrial utilization range of the oxide superconductive bulk material is expanded.

Claims (3)

  1. 単結晶状のRE 1+x Ba 2-x Cu 3y (REはY又は希土類元素から選ばれる1種又は2種以上の元素、−0.1≦x≦0.1、6.8≦y≦7.2)中にRE 2 BaCuO 5が微細分散した酸化物超電導バルク材料の製造方法であって、溶融状態から徐冷中に結晶成長させた酸化物超電導バルク材料の酸素量を酸素富化過程において富化する前に、 酸素分圧が0.00001気圧以上0.05気圧以下、 1000K以上、1250K以下の温度で前記結晶成長させた酸化物超電導バルク材料を熱処理する酸素富化前熱処理過程を有することを特徴とする酸化物超電導バルク材料の製造方法。 Single crystalline RE 1 + x Ba 2-x Cu 3 O y (RE is one or more elements selected from Y or a rare earth element, -0.1 ≦ x ≦ 0.1,6.8 ≦ a y ≦ 7.2) method of manufacturing an oxide superconducting bulk material RE 2 BaCuO 5 is finely dispersed in the oxygen-enriched process the oxygen content of the oxide superconductive bulk material obtained by crystal growth during the slow cooling from the molten state in prior enrichment, oxygen partial pressure is 0.00001 atm to 0.05 atm or less, more 1000 K, the oxygen-enriched before the heat treatment step of heat-treating an oxide superconducting bulk material obtained by the crystal growth at a temperature of 1250K method of manufacturing an oxide superconducting bulk material characterized by having.
  2. 前記酸素富化前熱処理過程後の酸化物超電導バルク材料の質量に対する前記酸素富化過程後の酸化物超電導バルク材料の質量の増分割合が、1mass%以上、1.5mass%以下であることを特徴とする請求項に記載の酸化物超電導バルク材料の製造方法。 Wherein the increment ratio of the mass of the oxide superconductive bulk material of the rear oxygen enrichment process to the mass of the oxide superconductive bulk material after said oxygen-enriched prior to heat treatment process, 1 mass% or more and less 1.5 mass% method of manufacturing an oxide superconducting bulk material according to claim 1,.
  3. 前記酸化物超電導バルク材料のRE元素が、La、Nd、Sm、Eu、Gd、Dyから選ばれる1種又は2種以上を含むことを特徴とする請求項1 又は2に記載の酸化物超電導バルク材料の製造方法。 The RE element of the oxide superconductive bulk material, La, Nd, Sm, Eu , Gd, oxide superconducting bulk according to claim 1 or 2, characterized in that it comprises one or more kinds selected from Dy method of manufacturing the material.
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