JPH01257160A - High density oxide superconducting sintered body and sintering method therefor - Google Patents
High density oxide superconducting sintered body and sintering method thereforInfo
- Publication number
- JPH01257160A JPH01257160A JP63084860A JP8486088A JPH01257160A JP H01257160 A JPH01257160 A JP H01257160A JP 63084860 A JP63084860 A JP 63084860A JP 8486088 A JP8486088 A JP 8486088A JP H01257160 A JPH01257160 A JP H01257160A
- Authority
- JP
- Japan
- Prior art keywords
- partial pressure
- oxygen partial
- sintered body
- oxide superconducting
- superconductor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000005245 sintering Methods 0.000 title claims abstract description 22
- 238000000034 method Methods 0.000 title claims description 8
- 239000001301 oxygen Substances 0.000 claims abstract description 55
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 55
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 54
- 239000002887 superconductor Substances 0.000 claims abstract description 30
- 239000000463 material Substances 0.000 claims abstract description 14
- 238000010494 dissociation reaction Methods 0.000 claims abstract description 11
- 208000018459 dissociative disease Diseases 0.000 claims abstract description 9
- 238000006243 chemical reaction Methods 0.000 claims abstract description 6
- 229910003098 YBa2Cu3O7−x Inorganic materials 0.000 abstract description 8
- 238000000137 annealing Methods 0.000 abstract description 7
- BERDEBHAJNAUOM-UHFFFAOYSA-N copper(I) oxide Inorganic materials [Cu]O[Cu] BERDEBHAJNAUOM-UHFFFAOYSA-N 0.000 abstract description 2
- KRFJLUBVMFXRPN-UHFFFAOYSA-N cuprous oxide Chemical compound [O-2].[Cu+].[Cu+] KRFJLUBVMFXRPN-UHFFFAOYSA-N 0.000 abstract 1
- 239000011800 void material Substances 0.000 abstract 1
- 239000000843 powder Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 5
- 230000000704 physical effect Effects 0.000 description 4
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000005593 dissociations Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- -1 oxygen ions Chemical class 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000004677 Nylon Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
Landscapes
- Superconductors And Manufacturing Methods Therefor (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明は、酸化物超伝導焼結体（以下、単に超伝導体
という。）およびその焼結法に関し、詳しくはＹ Ｂ
ａ ２ ＣＵ ３０７−ｘの組成をベースとしたペロブ
スカイト構造セラミックの超伝導体とその焼結方法に係
わるものである。[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an oxide superconducting sintered body (hereinafter simply referred to as a superconductor) and a sintering method thereof.
The present invention relates to a perovskite structure ceramic superconductor based on the composition of a 2 CU 307-x and a sintering method thereof.
（従来の技術）
一般に、Ｙ Ｂ ａ、 ２ Ｃｕ ３０ ｙ−Ｘで表わ
される層状ペロブスカイト構造セラミックの超伝導体は
９０Ｋ（ケルビン）級のＴｃ（電気抵抗がゼロになる温
度を示す。）を有するが、高密度の焼結体となすことが
困難で、通常２０〜３０％の空隙率となっている。そし
て、従来、この種の超伝導体は酸化物超伝導材料を常圧
の空気中で焼成するが、Ｗ１素気流中で焼成する方法に
より造られている。(Prior Art) Generally, a layered perovskite structure ceramic superconductor represented by YBa, 2 Cu 30 y-X has a Tc (indicates the temperature at which electrical resistance becomes zero) of 90K (Kelvin) class. However, it is difficult to form a high-density sintered body, and the porosity is usually 20 to 30%. Conventionally, this type of superconductor is produced by firing an oxide superconducting material in air at normal pressure, but by firing in a W1 elementary air flow.
（発明が解決しようとする課題）
前記超伝導体が高い空隙率であることは、超伝導体のＪ
ｃ（限界電流）を高くする上で大きな障害となっている
。また、この大きな空隙率は、元来この超伝導材料が空
気中の水蒸気や炭酸ガスと反応しやすいものであるため
、反応性を高め安定性を欠く原因になると同時に、この
超伝導材料の機械的強度を低下させることにもなり、線
材化などを実ｉする上で障害となっている。(Problem to be Solved by the Invention) The fact that the superconductor has a high porosity is due to the fact that the superconductor's J
This is a major obstacle in increasing c (limiting current). In addition, this large porosity causes this superconducting material to react easily with water vapor and carbon dioxide in the air, which increases reactivity and causes a lack of stability. This also reduces the physical strength of the material, which is an obstacle to making it into wire rods.
この超伝導体は主成分がＹＢａ２２Ｃｕ３Ｏ□−８より
なることから、その酸素の含有量が７−ｘで表示される
ように一定に＜Ｌり難いものである。Since the main component of this superconductor is YBa22Cu3O□-8, it is difficult for the oxygen content to be constant <L as expressed by 7-x.
しかしＸを小さくして、酸素の含有量を多くすることが
超伝導体のＴＣを高める上で有効であることが知られて
いる。従って、酸素分圧の高い雰囲気下で焼結すること
が望ましいが、本発明者の研究によれば、酸素分圧の高
い雰囲気下で焼結すると、緻密化が起り難く、この超伝
導体の緻密化は雰囲気のＦｉｌｌ素分圧素上圧大きく影
響を受けることが判明した。これは一般の酸化物の焼結
の際の酸素分圧への依存性と同じであり、酸素分圧（Ｐ
Ｏ２）が低い程、酸素イオンの欠陥１１度が高くなり、
拡散による物質移動が容易になり、焼結が促進されると
いう現象と同じである。そして、ペロブスカイト構造を
もつＹＢａ２Ｃｕ３Ｏ７−ｘの超伝導体は、結晶構造の
上からし、特にこの影響を受は易いものである。However, it is known that reducing X and increasing the oxygen content is effective in increasing the TC of a superconductor. Therefore, it is desirable to sinter in an atmosphere with a high oxygen partial pressure, but according to the research of the present inventors, sintering in an atmosphere with a high oxygen partial pressure makes it difficult to densify the superconductor. It has been found that densification is greatly influenced by the fill elemental partial pressure of the atmosphere. This is the same dependence on oxygen partial pressure during sintering of general oxides, and is the same as the dependence on oxygen partial pressure (P
The lower the O2), the higher the defect 11 degrees of oxygen ions,
This is the same phenomenon in which mass transfer by diffusion becomes easier and sintering is promoted. The YBa2Cu3O7-x superconductor having a perovskite structure is particularly susceptible to this influence due to its crystal structure.
そこで本発明者は超伝導体の物性研究において、超伝導
体を緻密化させかつ空隙率を低くなし得る焼結方法を実
験により知得して本発明を達成したちのである。Therefore, in researching the physical properties of superconductors, the present inventor discovered through experiments a sintering method that can densify superconductors and reduce porosity, thereby achieving the present invention.
すなわち、本発明の目的は本発明者の研究成東を利用し
て、超伝導体における前述した従来の高い空隙率の不都
合を解決けんとしたものであって、たとえば空隙率３，
５％の低空隙率で高密度の超伝導体およびその焼結方法
を提供するものである。That is, the purpose of the present invention is to solve the above-mentioned disadvantages of conventional high porosity in superconductors by utilizing the research conducted by the present inventor.
The present invention provides a high-density superconductor with a low porosity of 5% and a method for sintering the same.
（課題を解決するための手段）
第１発明の手段はＹＢａ２Ｃｕ３Ｏ７−ｘよりなる酸化
物超伝導材料が、大気の酸素分圧より低く、かつ反応式
％式％
による解離反応が起らないような酸素分圧下で焼結され
、続いて大気より高い酸素分圧下でアニール（低温焼成
）されて低空隙率の超伝導体とされてなる高密度超伝導
体とされる。なお、前記化学式中のＸは０．１より大ぎ
り０，９より小さい数値を示す（以下の化学式において
も同様である）。(Means for Solving the Problem) The means of the first invention is such that the oxide superconducting material made of YBa2Cu3O7-x has a partial pressure of oxygen lower than that of the atmosphere, and a dissociation reaction according to the reaction formula % formula % does not occur. A high-density superconductor is obtained by sintering under an oxygen partial pressure and then annealing (low-temperature firing) under an oxygen partial pressure higher than that of the atmosphere to form a low-porosity superconductor. Note that X in the above chemical formula represents a numerical value greater than 0.1 and less than 0.9 (the same applies to the following chemical formulas).
第２発明の手段はＹＢａ２Ｃｕ３Ｏ７−ｘよりなる酸化
物超伝導材料を焼結合成して高密度超伝導体となすに際
し、前記酸化物超伝導材料を、大気の酸素分圧より低く
、かつ反応式
％式％
による解離反応が起らないような酸素分圧下で焼結し、
続いて大気より高い酸素分圧下でアニールする工程より
なる高密度超伝導体の焼結法とされる。The means of the second invention is such that when sintering an oxide superconducting material consisting of YBa2Cu3O7-x to form a high-density superconductor, the oxide superconducting material has a pressure lower than the oxygen partial pressure of the atmosphere and a reaction formula of Sintered under oxygen partial pressure such that no dissociation reaction occurs due to formula %,
This method of sintering high-density superconductors is then followed by annealing under an oxygen partial pressure higher than that of the atmosphere.
前記アニールは人気より高い酸素分圧下、主として１４
ｉ１！Ｉ素の雰囲気中において初めの焼結時の焼結温度
より低温で高Ｔｃとなる所定時間、たとえば４００〜５
００℃で６〜４時間焼成される。また、アニールは、た
とえば９５０℃の初めの焼結後に炉内を酸素置換して大
気より高い酸素分圧下に保持し温度を下げながら炉冷し
てもよい。The annealing is performed under a higher oxygen partial pressure than is popular, mainly at 14
i1! A predetermined period of time in which a high Tc is achieved at a temperature lower than the sintering temperature during initial sintering in an atmosphere of I element, for example, 400 to 5
Baked at 00°C for 6-4 hours. Further, annealing may be performed by replacing the inside of the furnace with oxygen after initial sintering at 950° C., maintaining the oxygen partial pressure higher than that of the atmosphere, and cooling the furnace while lowering the temperature.
本発明は基本的には、大気中の酸素分圧、すなわら０．
２１ ａｔｍより低い酸素分圧下でまず焼結し、高密度
に焼結を実施し、続いて例えば純酸素などのような高い
酸素分圧下でアニールすることにより、ｎ密度、高ＴＯ
の超伝導体を得るものである。The present invention is basically based on the partial pressure of oxygen in the atmosphere, that is, 0.
n-density, high TO
This is to obtain a superconductor.
焼結時の酸素分圧は低い程望ましいが、一方では、次式
（１）の解離反応が起ることによってＹＢａ２Ｃｕ３Ｏ
７−ｘの超伝導体そのものが分解してしまうので、むや
みに低下させることはできない。The lower the oxygen partial pressure during sintering, the more desirable it is, but on the other hand, the dissociation reaction of the following formula (1) occurs, causing YBa2Cu3O
Since the 7-x superconductor itself will decompose, it cannot be reduced unnecessarily.
すなわち
２ＣｕＯ＝Ｃｕ２０＋ １／２０２ （１）この
解離反応（１）の標準ギブスエネルギー（ΔＧ０□）は
次の（２）式で表わされるが、その値は（３）式で計算
される。That is, 2CuO=Cu20+ 1/202 (1) The standard Gibbs energy (ΔG0□) of this dissociation reaction (1) is expressed by the following formula (2), and its value is calculated by formula (3).
ΔＧ０□＝ΔＨ０づΔＳ’ （２）ΔＧＯ丁 −Ａ
＋ＢＴＩＯ（ＪＴ −ト ＣＴ （３）＠：Ｊ
３、ΔＨはエンタルピー、ΔＳＯはエントロピー、王は
絶対温度を示し、（３）式のＡ、ＢおよびＣＧよ定数で
ある。ΔG0□=ΔH0zuΔS' (2) ΔGOd −A
+BTIO (JT - CT (3) @:J
3. ΔH is enthalpy, ΔSO is entropy, and King is absolute temperature, and A, B, and CG in equation (3) are constants.
一方（１）式より平衡定数には（４）式で表わされる。On the other hand, from equation (1), the equilibrium constant is expressed by equation (4).
１／２
に＝ （Ｐ ０２ ） （４）
従って、Ｒを気体定数とすると
ΔＧ ’ ＝ −ＲＴ ＩｎＫ （５）
より酸素分圧Ｐｏ２は次式で表わされる。To 1/2 = (P 02 ) (4)
Therefore, if R is a gas constant, ΔG' = −RT InK (5)
Therefore, the oxygen partial pressure Po2 is expressed by the following formula.
ＩｎＰｏ２＝−２ΔＧＯ／ＲＴ （６）（３）
式（７） Ａ ｋ： ３４．９５０ヲ、Ｂｋ：６．１ヲ
、そしてｃに−４４，３を代入（゛金属熱化学″第４版
０．クバシ１ウスキイ伯共著 丹羽員地蔵他共訳 産
業図書３４１頁参照。）し、各温度に於けるΔＧ０、を
計算し、この計算値を（６）式に代入すると、各温度に
於ける酸素分圧がわ出できる。InPo2=-2ΔGO/RT (6) (3)
Equation (7) A k: 34.950 wo, Bk: 6.1 wo, and -44.3 is substituted for c (``Metal Thermochemistry'' 4th edition 0. Co-authored by Count Kubashi 1 Ussky, co-translated by Kanjizo Niwa et al. (Refer to page 341 of Sangyo Tosho.) Then, by calculating ΔG0 at each temperature and substituting this calculated value into equation (6), the oxygen partial pressure at each temperature can be determined.
ＹＢａ２Ｃｕ３Ｏ７−ｘで表わされるペロブスカイト構
造の超伝導体の焼結は一般に９００〜１，０００℃で行
われる。本発明の焼結は０．２１ ａｔｍ以下にａ３い
てＰｏ２下で実施するものであるが、分離による分解が
起らないような最低の酸素分圧を必要とする。そのため
、（６）式で計算される、例えば９００℃、９５０℃お
よび１，０００”Ｃにおける平衡酸素分圧が０．０１４
． ０．０７７および０．１２１５ ａｔｍ以上の酸素
分圧でなければならない。Sintering of perovskite superconductors represented by YBa2Cu3O7-x is generally carried out at 900-1,000C. The sintering of the present invention, carried out under Po2 at a3 below 0.21 atm, requires the lowest oxygen partial pressure such that decomposition due to separation does not occur. Therefore, for example, the equilibrium oxygen partial pressure at 900°C, 950°C, and 1,000"C calculated using equation (6) is 0.014
．． Oxygen partial pressure must be greater than or equal to 0.077 and 0.1215 atm.
従って、本発明にあっては、人気中の酸素分目、すなわ
ら０．２１ ａｔｍより低く、しかも（１）式の解離反
応で規定される各温度における平衡酸素分圧以上の酸素
分圧下で焼結し、その侵、例えば純酸素などのような高
いＰａ累分圧下でアニールすることにより高密度、高Ｔ
ｃの超伝導体を得るものである。Therefore, in the present invention, the oxygen partial pressure is lower than the popular oxygen fraction, that is, 0.21 atm, and is higher than the equilibrium oxygen partial pressure at each temperature defined by the dissociation reaction of equation (1). High density, high T
This is to obtain a superconductor of c.
（作 用）
第１発明および第２発明において、超伝導材ネ＋１はＣ
ｕＯの解離が生じない酸素分圧下（Ｍ素不足の状態）で
焼結されることより緻密物性の焼結体となる。緻密物性
の焼結体は高酸素分圧下（酸素過剰の状態）のアニール
により物性の緻密性を１ｔ１うことなくＴｃ性能が発揮
された焼結体になる。(Function) In the first invention and the second invention, the superconducting material Ne+1 is C
By sintering under an oxygen partial pressure (M element deficiency state) where uO dissociation does not occur, a sintered body with dense physical properties is obtained. The sintered body with dense physical properties becomes a sintered body that exhibits Tc performance without losing the denseness of physical properties by annealing under high oxygen partial pressure (state of excess oxygen).
（実験例） 次に、本発明を実験例に基づいて説明する。(Experiment example) Next, the present invention will be explained based on experimental examples.
試薬特級のＹ Ｏ、ＢａＣｏ３およびＣｕ０の粉体を用
い最終の組成がＹＢａ２Ｃｕ３Ｏ７−ｘになるように、
それぞれ１／２．２および３のモル比になるように混合
した。混合は各粉体をポリエチレン類の容器に入れ、ナ
イロンをコートしたスチールボールを用い、ボットミル
上で９６時時間式混合して混合物を得た。混合物は乾燥
後、粉体とし、この粉体をアルミナ製のルツボに入れ、
９５０℃で３時間仮焼した、仮焼体はかなり強固に焼結
しているため、アルミナ製の乳鉢を用い粉砕混合を行っ
て仮焼した粉体（平均粒径１μｍ）を得た。なお、この
仮焼した粉体は市販の酸化物超伝導用原料粉（仮焼きパ
ウダ）を用いることができる。Using reagent-grade Y O, BaCo and Cu powder, the final composition was YBa2Cu3O7-x.
They were mixed at a molar ratio of 1/2.2 and 3, respectively. For mixing, each powder was placed in a polyethylene container and mixed using a nylon-coated steel ball on a bot mill for 96 hours to obtain a mixture. After drying, the mixture is made into powder, and this powder is placed in an alumina crucible.
The calcined body, which was calcined at 950° C. for 3 hours, was sintered quite strongly, so it was ground and mixed using an alumina mortar to obtain a calcined powder (average particle size of 1 μm). Note that, as this calcined powder, commercially available raw material powder for oxide superconductivity (calcined powder) can be used.
仮焼、粉砕の操作は３度くり返し、暗黒褐色のＹＢａ２
Ｃｕ３Ｏ７−ｘのベース粉体を得た。次いで、このベー
ス粉体１，６ｇを分取し、これを２５０ Ｋ９ ／ ｃ
ｍの圧力で直径１２ｍの円盤状に金型ブレスにて成形し
て成形体とした。成型体は所定数用意し、これら成形体
を常圧の酸素分圧０．２１ ａｔｌおよび空気、純酸素
、窒素を用いて調整した常圧以上および常圧以下の酸素
分圧の雰囲気気流中にて９５０℃、５時間焼成し、続い
てｌ１ｌｉ酸素１．ＯＯａｔｍの雰囲気気流中でアニー
ルして焼成体とした。The calcining and crushing operations were repeated three times, resulting in a dark brown YBa2.
A base powder of Cu3O7-x was obtained. Next, 1.6 g of this base powder was collected and heated at 250 K9/c.
The molded product was molded into a disc shape with a diameter of 12 m using a mold press under a pressure of m. A predetermined number of molded bodies are prepared, and these molded bodies are placed in an atmospheric air flow with an oxygen partial pressure of 0.21 atl at normal pressure and an oxygen partial pressure of above normal pressure and below normal pressure adjusted using air, pure oxygen, and nitrogen. and calcined at 950°C for 5 hours, followed by 1.1 liters of oxygen. The fired body was annealed in an OOatm atmosphere airflow.
初めの酸素分圧は０．２１ 、 ０．１５ 、 ０．１
０ 、 ０．０５．１．００にて行なった。萌記純Ｍ累
雰囲気気流中でのアニールは９５０℃、５時間焼成後、
毎分１０℃の割合で温度を下げるとともに、炉内を純酸
素１ ａｔｍに調整し５００’Ｃｋ：おイエ５ｒｆ１
間保持し、しかる後、炉冷した。各焼結体の空隙率は体
積と重Ｗから＝ｌ Ｒした。また、焼結体には銀ペース
トを用いて電極を焼きっけ接続し、電気抵抗を測定する
通常の４点法の試験よりこの焼結体のＴＣの測定をした
。The initial oxygen partial pressures are 0.21, 0.15, 0.1
0, 0.05.1.00. Moeki Pure M was annealed in a cumulative atmosphere airflow at 950°C for 5 hours.
While lowering the temperature at a rate of 10°C per minute, the inside of the furnace was adjusted to 1 atm of pure oxygen to 500'Ck: 5rf1
The mixture was kept for a while and then cooled in the oven. The porosity of each sintered body was calculated from the volume and weight W = l R. Further, an electrode was connected to the sintered body by baking using silver paste, and the TC of this sintered body was measured by a conventional four-point method test for measuring electrical resistance.
本実験例により得られた各焼結体（対照および焼結体１
〜４）の実験結果は数表に示す通りであった。Each sintered body obtained in this experimental example (control and sintered body 1
The experimental results of ~4) were as shown in the table.
１−表より、初めの酸素分圧は低い条件下で焼結したも
の程、空隙率が低下し、密度が上昇していることがわか
る。しかし焼も一体３のように、酸素分圧を前記した（
１）式の平衡酸素分圧以下に下げた場合には、解離によ
る超伝導体のペロブスカイト相が分解しＣｄ２Ｏ相が生
成して赤色になった。From Table 1, it can be seen that the lower the initial oxygen partial pressure is, the lower the porosity and the higher the density. However, as in Part 3, the oxygen partial pressure was described above (
When the pressure was lowered to below the equilibrium oxygen partial pressure in equation 1), the perovskite phase of the superconductor due to dissociation decomposed and a Cd2O phase was generated, resulting in a red color.
焼結体３のように分解したものは、アニールにより超伝
導体のペロブスカイト相が再合成されず、ここまで低い
酸素分圧下での焼結は不可能であつた。In the case of decomposed sintered body 3, the perovskite phase of the superconductor was not resynthesized by annealing, and sintering at such a low oxygen partial pressure was impossible.
ｎ酸素分圧下で焼結し、純酸素１．００ ａｔｍの雰囲
気中でアニールした焼結体４は空隙率を低くすることが
できなかった。対照の焼結体、および焼結体１．２．４
はＴＣ９０Ｋを示した。The sintered body 4, which was sintered under n oxygen partial pressure and annealed in an atmosphere of 1.00 atm of pure oxygen, could not have a low porosity. Control sintered body and sintered body 1.2.4
indicated TC90K.
（発明の効果）
第１発明は、Ｙ Ｂ ａ Ｃｕ ３０７−ｘの超伝導
材料を人気の酸素分圧より低く、かつＣｕＯの分離反応
が生じない酸素分圧下で焼成され、次いで大気よりｎい
酸素分圧下でアニールされてなる超伝導体であるため、
たとえば３．５％の低空隙率の緻密になし得てかつＴＣ
をたとえば９０にのような高い温度のものとされる。(Effects of the Invention) The first invention is that the superconducting material YB a Cu 307-x is fired under an oxygen partial pressure lower than the popular oxygen partial pressure and no separation reaction of CuO occurs, and then Because it is a superconductor annealed under oxygen partial pressure,
For example, it can be made dense with a low porosity of 3.5% and TC
It is assumed that the temperature is as high as, for example, 90°C.
そして第２発明は、ＹＢａ２Ｃｕ３Ｏ７−ｘよりなる超
伝導材料を大気の酸素分圧より低く、かつＣｕＯの解離
反応が生じない酸素分圧下で焼結し、続いて大気より高
い酸素分圧下でアニールする工程よりなるので、たとえ
ば３，５％の低空隙率でかつ緻密な超伝導体になし得る
。In the second invention, a superconducting material made of YBa2Cu3O7-x is sintered under an oxygen partial pressure that is lower than the atmospheric oxygen partial pressure and does not cause a dissociation reaction of CuO, and then annealed under an oxygen partial pressure that is higher than the atmospheric oxygen partial pressure. Since it consists of several steps, it is possible to produce a dense superconductor with a low porosity of, for example, 3.5%.
出願人 財団法人ファインセラミックスセンター代理人
弁理士 岡田英彦（外３名）Applicant Fine Ceramics Center Foundation Representative Patent Attorney Hidehiko Okada (3 others)
Claims (2)
物超伝導材料が、大気の酸素分圧より低く、かつ反応式
２ＣＵ０＝ＣＵ＿２Ｏ＋１／２Ｏ＿２ による解離反応が起らないような酸素分圧下で焼結され
、続いて大気より高い酸素分圧下でアニールされて低空
隙率の超伝導体とされてなることを特徴とした高密度酸
化物超伝導焼結体。(1) An oxide superconducting material consisting of YBa_2Cu_3O_7_-_x is sintered under an oxygen partial pressure that is lower than the atmospheric oxygen partial pressure and does not cause the dissociation reaction according to the reaction formula 2CU0=CU_2O+1/2O_2, and then A high-density oxide superconducting sintered body characterized by being annealed under an oxygen partial pressure higher than atmospheric pressure to form a low-porosity superconductor.
物超伝導材料を焼結合成して高密度超伝導体となすに際
し、前記酸化物超伝導材料を、大気の酸素分圧より低く
、かつ反応式 ２ＣＵＯ＝ＣＵ＿２Ｏ＋１／２Ｏ＿２ による解離反応が起らないような酸素分圧下で焼結し、
続いて大気より高い酸素分圧下でアニールすることを特
徴としたｎ密度酸化物超伝導焼結体の焼結法。(2) When sintering an oxide superconducting material consisting of YBa_2Cu_3O_7_-_x to form a high-density superconductor, the oxide superconducting material is heated at a pressure lower than the oxygen partial pressure of the atmosphere, and the reaction formula 2CUO=CU_2O+1 /2O_2 is sintered under an oxygen partial pressure that does not cause a dissociation reaction,
A method for sintering an n-density oxide superconducting sintered body, which is then annealed under an oxygen partial pressure higher than atmospheric pressure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63084860A JPH01257160A (en) | 1988-04-06 | 1988-04-06 | High density oxide superconducting sintered body and sintering method therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63084860A JPH01257160A (en) | 1988-04-06 | 1988-04-06 | High density oxide superconducting sintered body and sintering method therefor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01257160A true JPH01257160A (en) | 1989-10-13 |
Family
ID=13842563
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63084860A Pending JPH01257160A (en) | 1988-04-06 | 1988-04-06 | High density oxide superconducting sintered body and sintering method therefor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01257160A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03159954A (en) * | 1989-11-13 | 1991-07-09 | Ceracon Inc | Manufacture of product having improved physical characteristics and superconductivity |
| CN111039663A (en) * | 2019-12-30 | 2020-04-21 | 中国工程物理研究院电子工程研究所 | Sintering method of alumina ceramic |
-
1988
- 1988-04-06 JP JP63084860A patent/JPH01257160A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03159954A (en) * | 1989-11-13 | 1991-07-09 | Ceracon Inc | Manufacture of product having improved physical characteristics and superconductivity |
| CN111039663A (en) * | 2019-12-30 | 2020-04-21 | 中国工程物理研究院电子工程研究所 | Sintering method of alumina ceramic |
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