JPH0572332B2 - - Google Patents
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- Publication number
- JPH0572332B2 JPH0572332B2 JP5458988A JP5458988A JPH0572332B2 JP H0572332 B2 JPH0572332 B2 JP H0572332B2 JP 5458988 A JP5458988 A JP 5458988A JP 5458988 A JP5458988 A JP 5458988A JP H0572332 B2 JPH0572332 B2 JP H0572332B2
- Authority
- JP
- Japan
- Prior art keywords
- spray
- temperature
- solvent
- solution
- metal
- 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.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 claims description 32
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical group OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 18
- 229910052751 metal Inorganic materials 0.000 claims description 17
- 239000002184 metal Substances 0.000 claims description 17
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 15
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 12
- 239000002994 raw material Substances 0.000 claims description 10
- 150000007524 organic acids Chemical class 0.000 claims description 9
- 239000003960 organic solvent Substances 0.000 claims description 9
- 239000007864 aqueous solution Substances 0.000 claims description 8
- 239000007921 spray Substances 0.000 claims description 8
- 150000003839 salts Chemical class 0.000 claims description 6
- 238000005118 spray pyrolysis Methods 0.000 claims description 6
- 239000002887 superconductor Substances 0.000 claims description 6
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- 239000011575 calcium Chemical class 0.000 claims description 4
- 239000010949 copper Chemical class 0.000 claims description 4
- 238000000197 pyrolysis Methods 0.000 claims description 4
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims description 3
- 239000012046 mixed solvent Substances 0.000 claims description 3
- 230000002194 synthesizing effect Effects 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical class [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical class [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052797 bismuth Inorganic materials 0.000 claims description 2
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical class [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 claims description 2
- 229910052791 calcium Inorganic materials 0.000 claims description 2
- 229910052802 copper Chemical class 0.000 claims description 2
- 239000011259 mixed solution Substances 0.000 claims description 2
- 229910052712 strontium Inorganic materials 0.000 claims description 2
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical class [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 description 14
- 239000000203 mixture Substances 0.000 description 14
- 239000002245 particle Substances 0.000 description 14
- 239000000243 solution Substances 0.000 description 10
- 239000010419 fine particle Substances 0.000 description 9
- 239000012071 phase Substances 0.000 description 9
- 239000000523 sample Substances 0.000 description 7
- 239000002904 solvent Substances 0.000 description 7
- -1 citric acid to this Chemical class 0.000 description 6
- 239000000843 powder Substances 0.000 description 6
- 238000003786 synthesis reaction Methods 0.000 description 6
- 150000004703 alkoxides Chemical class 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000000975 co-precipitation Methods 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 239000011164 primary particle Substances 0.000 description 4
- 238000010298 pulverizing process Methods 0.000 description 4
- 238000007711 solidification Methods 0.000 description 4
- 238000001694 spray drying Methods 0.000 description 4
- KRKNYBCHXYNGOX-UHFFFAOYSA-K Citrate Chemical compound [O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O KRKNYBCHXYNGOX-UHFFFAOYSA-K 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 230000008023 solidification Effects 0.000 description 3
- 238000005507 spraying Methods 0.000 description 3
- 238000005979 thermal decomposition reaction Methods 0.000 description 3
- AEMRFAOFKBGASW-UHFFFAOYSA-N Glycolic acid Chemical compound OCC(O)=O AEMRFAOFKBGASW-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910001960 metal nitrate Inorganic materials 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 238000000634 powder X-ray diffraction Methods 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000011163 secondary particle Substances 0.000 description 2
- 235000002906 tartaric acid Nutrition 0.000 description 2
- 239000011975 tartaric acid Substances 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 229910015901 Bi-Sr-Ca-Cu-O Inorganic materials 0.000 description 1
- 229910014454 Ca-Cu Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000005262 decarbonization Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- IDGUHHHQCWSQLU-UHFFFAOYSA-N ethanol;hydrate Chemical compound O.CCO IDGUHHHQCWSQLU-UHFFFAOYSA-N 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000001879 gelation Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 239000004310 lactic acid Substances 0.000 description 1
- 235000014655 lactic acid Nutrition 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000012488 sample solution Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000003746 solid phase reaction Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000000859 sublimation Methods 0.000 description 1
- 230000008022 sublimation Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011882 ultra-fine particle Substances 0.000 description 1
Description
【発明の詳細な説明】
「産業上の利用分野」
本発明は酸化物高温超伝導体の原料合成法に関
するものである。DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for synthesizing raw materials for oxide high temperature superconductors.
「従来技術及びその問題点」
従来、酸化物高温超伝導材料の化学的手法によ
る合成法としては、(1)蒸発法、(2)共沈法、(3)金属
アルコキシド法、(4)固相反応法等が知られてい
る。"Prior art and its problems" Conventionally, chemical synthesis methods for oxide high-temperature superconducting materials include (1) evaporation method, (2) coprecipitation method, (3) metal alkoxide method, and (4) solidification method. Phase reaction methods and the like are known.
しかして、上述(1)の蒸発法は、ビスマス、スト
ロンチウム、カルシウム、銅等の目的とする組成
比の金属塩の混合水溶液を加熱して、溶媒を除去
することにより乾燥試料を得、これを粉砕し、焼
成することにより原料粉末を得る方法であるが、
溶媒除去に際して各成分の溶解度差、分解・昇華
等の影響で組成の不均一性や組成全体の変動が生
じやすいことや、粉砕工程が必要かつ試料汚染の
問題が起こる。 Therefore, in the evaporation method described in (1) above, a dry sample is obtained by heating a mixed aqueous solution of metal salts of a desired composition ratio such as bismuth, strontium, calcium, copper, etc. and removing the solvent. This is a method of obtaining raw material powder by pulverizing and firing.
When removing the solvent, non-uniformity and fluctuations in the overall composition tend to occur due to differences in the solubility of each component, decomposition, sublimation, etc., as well as the need for a pulverization process and the problem of sample contamination.
(2)の共沈法は、金属塩の混合水溶液に沈澱剤を
加えて単塩または複塩の沈澱粒子を形成させ、こ
れをろ過、乾燥、焼成することにより比較的容易
に1μｍ以下〜数μｍの微粒子原料を合成するこ
とが可能である。しかし、多成分系の場合、完全
同時沈澱は理論上不可能であり、希望する組成比
の沈澱を得ることは困難である。 In the coprecipitation method (2), a precipitant is added to a mixed aqueous solution of metal salts to form precipitated particles of a single or double salt, which are then filtered, dried, and calcined. It is possible to synthesize micron particle raw materials. However, in the case of a multi-component system, complete simultaneous precipitation is theoretically impossible, and it is difficult to obtain a precipitate with a desired composition ratio.
(3)の金属アルコキシド法は、金属アルコキシド
溶液の加水分解により数10nｍ程度の超微粒子を
合成することが可能であるが、出発原料の金属ア
ルコキシドが非常に高価であり、多成分系の場合
は、それぞれの金属の溶解度が実用上問題がない
程度に高い有機溶媒が必要となり、また複合アル
コキシドの合成が困難であるため、沈澱粒子の組
成の不均一性に関して共沈法と同様の欠点を持
つ。 In the metal alkoxide method (3), it is possible to synthesize ultrafine particles of several tens of nanometers by hydrolyzing a metal alkoxide solution, but the metal alkoxide as a starting material is very expensive, and in the case of a multi-component system, , it requires an organic solvent in which the solubility of each metal is high enough to pose no practical problem, and it is difficult to synthesize composite alkoxides, so it has the same drawbacks as the coprecipitation method in terms of compositional heterogeneity of precipitated particles. .
(4)固相反応法は酸化物、炭酸塩等の形で各成分
を混合し、仮焼、粉砕の過程を繰り返すことによ
つて目的とする相の均質な粉体を得ようとするも
のであるが、生成粒子径は一般に大きくなり、粉
砕過程において試料汚染の問題が避けられない。 (4) The solid phase reaction method attempts to obtain a homogeneous powder with the desired phase by mixing each component in the form of oxides, carbonates, etc. and repeating the calcining and pulverizing processes. However, the diameter of the generated particles is generally large, and the problem of sample contamination during the grinding process is unavoidable.
「発明の概要」
本発明はこれらの欠点を解消し、微粒で均質
な、低温での合成が可能で易焼結性を有する、酸
化物高温超伝導体用の合成原料を提供することを
目的とする。"Summary of the Invention" The purpose of the present invention is to eliminate these drawbacks and provide a synthetic raw material for oxide high-temperature superconductors that is fine-grained and homogeneous, can be synthesized at low temperatures, and has easy sinterability. shall be.
本発明者は、酸化物高温超伝導体の原料合成方
法の研究を進める過程で、クエン酸塩法などの有
機酸を使用する方法を均質微粒子の合成に適用す
ることを検討してきた。金属硝酸塩水溶液等から
の粉末合成では、多くの場合硝酸塩等の中間化合
物が析出し、難分解性化合物が生じる場合は熱弁
解−合成過程が妨げられたり、また組成の不均一
化が生じ易い。一方、金属クエン酸塩等を用いた
場合、PHコントロール等の適切な条件設定により
非晶質からの目的相合成も可能であるが、通常の
加熱によるゲル化・固化過程を径ると、一次粒子
径は比較的微細であるが凝集度の高い固結した塊
状物を形成し、単分散粒子として原料に用いるた
めには微粉砕処理が必要となる。そこで固化また
は熱分解を微粒の液滴状態の試料に対して行え
ば、微粒のゲル化乾燥物が得られ、熱分解や脱炭
素処理が容易に行われ、最終的に単分散化しやす
い粉体が得られるものと考え、適当な条件下で金
属クエン酸塩等の溶液を噴霧乾燥−熱分解処理ま
たは噴霧熱分解処理することでこれが達成される
ことを見いだし本発明に到達した。 In the process of researching methods for synthesizing raw materials for oxide high-temperature superconductors, the present inventor has considered applying methods using organic acids, such as the citrate method, to the synthesis of homogeneous fine particles. In powder synthesis from an aqueous solution of metal nitrates, intermediate compounds such as nitrates often precipitate, and if difficult-to-decompose compounds are produced, the thermal synthesis process may be hindered or the composition may become non-uniform. On the other hand, when using metal citrate, etc., it is possible to synthesize the desired phase from amorphous by setting appropriate conditions such as PH control, but if you go through the gelation and solidification process by normal heating, Although the particle size is relatively fine, it forms solidified lumps with a high degree of agglomeration, and in order to use them as raw materials as monodispersed particles, pulverization treatment is required. Therefore, if solidification or thermal decomposition is performed on a sample in the form of fine droplets, a fine gelled dried product can be obtained, which can be easily thermally decomposed or decarbonized, and finally becomes a powder that is easy to monodisperse. We thought that this could be obtained, and found that this could be achieved by subjecting a solution of metal citrate or the like to spray drying-pyrolysis treatment or spray pyrolysis treatment under appropriate conditions, and thus arrived at the present invention.
すなわち本発明は、目的の酸化物高温超伝導
体組成となるように酢酸塩、硝酸塩等の金属塩混
合水溶液を調製し。これにクエン酸等の有機酸を
加え、さらに水酸基を持つ有機溶媒としてエタノ
ール、エチレングリコール等またはこれらと水と
の混合溶媒を加え均一になるよう攪拌し、この
溶液を室温または100℃以下に加温し、適当な条
件下で噴霧乾燥−熱分解処理または噴霧熱分解処
理することにより、組成の均一な、熱分解後の１
次粒子径２〜3μｍ以下の微粒子を得ることを特
徴とする。以下に本発明を詳細に説明する。 That is, in the present invention, a mixed aqueous solution of metal salts such as acetate and nitrate is prepared so as to have the desired composition of an oxide high temperature superconductor. Add an organic acid such as citric acid to this, then add ethanol, ethylene glycol, etc. or a mixed solvent of these and water as an organic solvent with a hydroxyl group, stir until uniform, and heat this solution to room temperature or below 100℃. By heating and spray-drying-pyrolysis treatment or spray-pyrolysis treatment under appropriate conditions, 1 with a uniform composition after pyrolysis
It is characterized by obtaining fine particles with a secondary particle diameter of 2 to 3 μm or less. The present invention will be explained in detail below.
まず、金属塩水溶液の濃度は、噴霧乾燥または
噴霧熱分解時における２次粒子径および粒子の捕
集効率を左右するので、0.01〜0.5M／程度が
望ましい。これにクエン酸等の有機酸を加える。
有機酸の種類は酒石酸、乳酸、グリコール酸等の
カルボキシル基と水酸基を同時に持つもののいず
れでもよいが、コストの面や、炭素の量が多いと
後の脱炭素処理を十分に行わないといけないこと
などを考慮してクエン酸を用いた。さらにエタノ
ール、エチレングリコール等の有機溶媒単独また
は水との混合溶媒を加えて十分に混合攪拌する。
エタノール、エチレングリコール等の量は噴霧条
件に応じて調節する。 First, the concentration of the metal salt aqueous solution influences the secondary particle diameter and particle collection efficiency during spray drying or spray pyrolysis, and is therefore preferably about 0.01 to 0.5 M/. Add an organic acid such as citric acid to this.
The type of organic acid may be one that has both a carboxyl group and a hydroxyl group, such as tartaric acid, lactic acid, or glycolic acid, but it is expensive, and if the amount of carbon is large, sufficient decarbonization treatment must be performed afterwards. Citric acid was used in consideration of the following. Further, an organic solvent such as ethanol or ethylene glycol alone or a mixed solvent with water is added and thoroughly mixed and stirred.
The amount of ethanol, ethylene glycol, etc. is adjusted depending on the spraying conditions.
この溶液を室温または加温（溶媒が沸騰しない
程度、例えばエチレングリコールを加えた場合は
約90℃）しながら混合攪拌することにより、溶液
の温度によつてはNOx、H2O等の蒸発を伴つて、
金属有機酸塩が溶媒中に溶質として分散した状態
になる。溶媒の蒸発が十分進んだものは、冷却す
るとゲル化し溶液の粘性が高くなつて噴霧処理し
にくくなるので、適当な粘度となるように加温状
態で噴霧処理するか、有機酸と有機溶媒の組合せ
により金属有機酸塩を生成しやすいものを選択す
るかまたは反応を溶液調製−噴霧熱処理の両過程
を通じて行うようにする。これらの結果、有機酸
のカルボキシル基が金属イオンとまた水酸基が有
機溶媒と親和力を強くして、金属有機酸塩が溶媒
中に均一に分散した状態となる。硝酸を用いる場
合は加熱により途中で加水分解反応が生じないよ
うに注意する必要がある。 Depending on the temperature of the solution, evaporation of NOx, H 2 O, etc. can be prevented by mixing and stirring this solution at room temperature or while heating it (at a temperature that does not boil the solvent, for example, about 90°C if ethylene glycol is added). Accompanied by
The metal organic acid salt becomes dispersed as a solute in the solvent. If the solvent has sufficiently evaporated, it will turn into a gel when cooled, increasing the viscosity of the solution and making it difficult to spray. Therefore, spraying should be carried out in a heated state to achieve an appropriate viscosity, or a mixture of organic acid and organic solvent should be used. Select a combination that will easily produce a metal organic acid salt, or carry out the reaction through both the process of solution preparation and spray heat treatment. As a result, the carboxyl group of the organic acid has a strong affinity with the metal ion and the hydroxyl group with the organic solvent, resulting in a state in which the metal organic acid salt is uniformly dispersed in the solvent. When using nitric acid, care must be taken not to cause a hydrolysis reaction during heating.
より均質化のためにas−preraredの生成物を非
生質とする場合はPHコントロール等を行い、噴霧
乾燥または熱分解過程を通じての中間化合物相の
晶出を抑制する等の手段をとる。 If the as-prerared product is to be made non-vital in order to be more homogenized, measures such as pH control and the like are taken to suppress crystallization of intermediate compound phases through spray drying or thermal decomposition processes.
このようにして調製した溶液を、加圧空気によ
る噴霧、超音波発振による霧化等の方法で数
10μm以下の微小液滴とし、噴霧乾燥の場合は100
〜200℃程度の乾燥空気中、噴霧熱分解の場合は
600〜1800℃程度の炉中ないしはプラズマ、化学
炎中に導入する。温度、噴霧液滴径、滞留時間等
の噴霧に関する諸条件は試料溶液の量、濃度、溶
媒・溶質の種類、処理容器の形状、試料の捕集方
法等の条件に応じて最適条件を選ぶ必要がある。 The solution prepared in this way is sprayed with pressurized air, atomized with ultrasonic oscillation, etc.
Micro droplets of 10μm or less, 100μm for spray drying
In the case of spray pyrolysis in dry air at ~200℃
Introduce into a furnace, plasma, or chemical flame at a temperature of about 600 to 1800℃. Various conditions related to spraying, such as temperature, spray droplet diameter, and residence time, need to be selected optimally according to conditions such as the amount of sample solution, concentration, type of solvent/solute, shape of processing container, and sample collection method. There is.
サイクロン、フイルタリング、静電捕集等の方
法により捕集された微粒子に対しては、噴霧熱分
解により完全に分解−結晶化が行われた場合を除
いて熱処理する必要がある。試料組成により熱処
理温度・時間は異なるが、例えば
Bi4Sr3Ca3Cu4Oyの場合は820〜830℃で約３時間
熱処理することによりBi−Sr−Ca−Cu−Ｏ系に
おける超伝導相の結晶構造を示すことが粉末Ｘ線
回折により確かめられた（第１図）。熱処理後に
得られた微粒子の粒子径は１次粒子径２〜3μm以
下の微粒子であり、分析電子顕微鏡によるバルク
及び微小領域の組成分析結果から、ストイキオメ
トリーが保たれかつ均一組成であることが確認さ
れた。 Fine particles collected by methods such as cyclone, filtering, and electrostatic collection need to be heat treated unless they are completely decomposed and crystallized by spray pyrolysis. The heat treatment temperature and time vary depending on the sample composition, but for example,
In the case of Bi 4 Sr 3 Ca 3 Cu 4 O y , powder X-ray diffraction shows that the crystal structure of the superconducting phase in the Bi-Sr-Ca-Cu-O system is shown by heat treatment at 820 to 830°C for about 3 hours. This was confirmed by (Figure 1). The particle size of the fine particles obtained after heat treatment is fine particles with a primary particle size of 2 to 3 μm or less, and the composition analysis results of the bulk and micro regions using an analytical electron microscope indicate that the stoichiometry is maintained and the composition is uniform. confirmed.
こうして得られた原料粉体は、共沈法等の他の
方法で得られた粒子に比べて熱処理前の段階で高
い均一性を保つており、微粒子であることに加え
て熱処理時の分解−結晶化の反応が容易に行われ
ることから、他の方法に比べて低温での合成が可
能であり、また焼結性の向上による焼結体の緻密
化が容易となる。また金属有機酸塩のゲル化−固
化法に比べると、熱分解時の粒子の反応性に富む
ので熱処理過程が容易となり、また単分散化しや
すい。 The raw material powder obtained in this way maintains high uniformity before heat treatment compared to particles obtained by other methods such as coprecipitation, and in addition to being fine particles, it decomposes during heat treatment. Since the crystallization reaction is easily performed, synthesis can be performed at a lower temperature than other methods, and the sintered body can be easily densified due to improved sinterability. Furthermore, compared to the gelation-solidification method of metal organic acid salts, the particles are highly reactive during thermal decomposition, making the heat treatment process easier and monodispersion easier.
また他の化学的な合成法に比べて途中での沈澱
条件のコントロールの必要や組成変動の心配もな
く、対象とする元素や組成を変えた場合への応用
も広い。また処理装置のスケールアツプによる量
産化が容易である。 In addition, compared to other chemical synthesis methods, there is no need to control precipitation conditions during the process, and there is no need to worry about compositional changes, so it can be widely applied to cases where the target element or composition is changed. Moreover, mass production is easy by scaling up the processing equipment.
「実施例」 次に実施例を挙げて本発明を説明する。"Example" Next, the present invention will be explained with reference to Examples.
実施例 １
0.015M／のBi4Sr3Ca3Cu4Oyの硝酸塩水溶液
700mlを調製し、これに有機酸として0.09molの
クエン酸を加え混合攪拌した。さらに有機溶媒と
してエチレングリコールを0.15mol加え、十分に
混合攪拌しながら60℃で加熱した。さらにエタノ
ールを300ml加え、温度を60〜70℃に保ちよく攪
拌しながら、スプレードライヤーで噴霧乾燥処理
を以下の条件で行つた。２流体ノズル式噴霧、乾
燥チヤンバ入口温度200℃、出口温度100℃、噴霧
空気圧2.0Kg／cm2、吸引空気量0.40m3／min、試料
供給量８cm3／min。Example 1 Nitrate aqueous solution of 0.015M/Bi 4 Sr 3 Ca 3 Cu 4 O y
700 ml was prepared, and 0.09 mol of citric acid was added thereto as an organic acid, followed by mixing and stirring. Furthermore, 0.15 mol of ethylene glycol was added as an organic solvent, and the mixture was heated at 60° C. while thoroughly mixing and stirring. Furthermore, 300 ml of ethanol was added, and while the temperature was maintained at 60 to 70°C and the mixture was thoroughly stirred, spray drying was performed using a spray dryer under the following conditions. Two-fluid nozzle spray, drying chamber inlet temperature 200℃, outlet temperature 100℃, spray air pressure 2.0Kg/cm 2 , suction air volume 0.40m 3 /min, sample supply rate 8cm 3 /min.
サイクロンにより捕集された粉体は微細な内部
構造を有する径１〜数μｍ程度の乾燥粒子により
なる。これを170℃で加熱し黒化させた後、820℃
３時間焼成することにより、Bi−Sr−Ca−Cu系
での超伝導相の結晶構造を示す、１次粒子径２〜
3μm以下の弱凝集粒子が得られた。この凝集体を
アトリシヨンミルで解砕処理して得られた原料を
用いて作成した焼結体は理論密度の92％の密度を
持ち、Tc＝91Kの超伝導特性を示した。 The powder collected by the cyclone consists of dry particles having a diameter of about 1 to several μm and having a fine internal structure. After heating this at 170℃ to blacken it, 820℃
By firing for 3 hours, the primary particle size is 2 to 2, which shows the crystal structure of the superconducting phase in the Bi-Sr-Ca-Cu system.
Weakly agglomerated particles of 3 μm or less were obtained. A sintered body created using the raw material obtained by crushing this aggregate with an attrition mill had a density of 92% of the theoretical density and exhibited superconductivity with Tc = 91K.
実施例 ２
実施例１と同じ量の金属硝酸塩水溶液に、有機
酸として酒石酸を同量、有機溶媒としてエタノー
ルを400ml加え、60℃で混合攪拌した。この溶液
を実施例１よりチヤンバ入口・出口を各々20℃低
い温度で噴霧乾燥処理した。実施例１と同様の熱
処理により１次粒子径２〜3μm以下の超伝導相の
凝集粒子が得られた。Example 2 To the same amount of metal nitrate aqueous solution as in Example 1, the same amount of tartaric acid as an organic acid and 400 ml of ethanol as an organic solvent were added and mixed and stirred at 60°C. This solution was spray-dried at a temperature 20° C. lower at the chamber inlet and outlet than in Example 1, respectively. By the same heat treatment as in Example 1, aggregated particles of superconducting phase having a primary particle diameter of 2 to 3 μm or less were obtained.
実施例 ３
実施例１と同じ金属クエン酸−有機溶媒混合溶
液を調製し水−エタノール溶液で３倍に希釈し、
約1.5MHzの超音波発振により霧化を行い数μｍ
の液滴を生成させ、中心温度約900℃に保つた石
英反応管中に導入し（流速約10cm／min）、熱分
解させた粒子をフイルタリングにより回収し、さ
らに820℃１時間の熱処理により超伝導相の単分
散微粒子（１次粒子径約2μm）が得られた。Example 3 The same metal citric acid-organic solvent mixed solution as in Example 1 was prepared and diluted 3 times with a water-ethanol solution.
Atomization is performed by ultrasonic oscillation of approximately 1.5MHz to a size of several μm.
droplets were generated and introduced into a quartz reaction tube maintained at a center temperature of approximately 900°C (flow rate approximately 10cm/min), the thermally decomposed particles were collected by filtering, and further heat-treated at 820°C for 1 hour. Monodisperse fine particles (primary particle diameter of about 2 μm) of superconducting phase were obtained.
「発明の効果」
本発明は以上説明したように、他法に比べてよ
り低温で合成可能な、易結晶性の、酸化物高温超
伝導体の均一組成の微粒子原料を容易に製造する
ものであり、臨界電流密度の向上など超伝導材料
の実用化を促進するものとして期待される。"Effects of the Invention" As explained above, the present invention is capable of easily producing a fine particle raw material with a uniform composition of an easily crystallized oxide high-temperature superconductor that can be synthesized at a lower temperature than other methods. This is expected to promote the practical application of superconducting materials, such as improving critical current density.
第１図は本方法により生成した超伝導相微粒子
の粉末Ｘ線回折パターンで、図中の（○○○）は
各回折ピークに相当する面指数を表す。
FIG. 1 shows a powder X-ray diffraction pattern of superconducting phase fine particles produced by this method, and (○○○) in the figure represents a surface index corresponding to each diffraction peak.
Claims (1)
の金属塩混合水溶液に、水酸基とカルボキシル基
の両方を持つクエン酸等の有機酸と、エチレング
リコール、エタノール等の水酸基を持つ有機溶媒
単独または水との混合溶媒を加え、撹拌により均
一混合溶液とし、これを噴霧乾燥−熱分解、また
は噴霧熱分解処理することによる、酸化物高温超
伝導体に用いる微粒子原料の合成法。1 Add an organic acid such as citric acid that has both hydroxyl groups and carboxyl groups and an organic solvent having hydroxyl groups such as ethylene glycol or ethanol alone or as a mixed solvent with water to a mixed aqueous solution of metal salts of bismuth, strontium, calcium, and copper. In addition, a method for synthesizing a particulate raw material for use in an oxide high-temperature superconductor by forming a homogeneous mixed solution by stirring and subjecting this to spray drying-pyrolysis or spray pyrolysis treatment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5458988A JPH01226724A (en) | 1988-03-08 | 1988-03-08 | Method for synthesizing fine oxide particles as starting material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5458988A JPH01226724A (en) | 1988-03-08 | 1988-03-08 | Method for synthesizing fine oxide particles as starting material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01226724A JPH01226724A (en) | 1989-09-11 |
| JPH0572332B2 true JPH0572332B2 (en) | 1993-10-12 |
Family
ID=12974909
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5458988A Granted JPH01226724A (en) | 1988-03-08 | 1988-03-08 | Method for synthesizing fine oxide particles as starting material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01226724A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0774454B2 (en) * | 1989-10-27 | 1995-08-09 | 工業技術院長 | Manufacturing method of oxide fine particle deposition film |
| FR2659961A1 (en) * | 1990-03-23 | 1991-09-27 | Rhone Poulenc Chimie | PROCESS FOR THE PREPARATION OF SUPERCONDUCTING PHASES BASED ON BISMUTH, STRONTIUM, CALCIUM AND COPPER AND A STABILIZING ELEMENT. |
| US5480862A (en) * | 1993-07-30 | 1996-01-02 | Pirelli Cavi S.P.A. | Method for the preparation of precursors for superconductors and compounds thus obtained |
| US8361619B2 (en) * | 2006-09-07 | 2013-01-29 | Sud-Chemie Ag | Process for preparing nanocrystalline mixed metal oxides |
-
1988
- 1988-03-08 JP JP5458988A patent/JPH01226724A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01226724A (en) | 1989-09-11 |
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