JPH03208279A - Connection of compound superconducting wire - Google Patents
Connection of compound superconducting wireInfo
- Publication number
- JPH03208279A JPH03208279A JP277990A JP277990A JPH03208279A JP H03208279 A JPH03208279 A JP H03208279A JP 277990 A JP277990 A JP 277990A JP 277990 A JP277990 A JP 277990A JP H03208279 A JPH03208279 A JP H03208279A
- Authority
- JP
- Japan
- Prior art keywords
- powder
- filaments
- connection
- superconducting
- nb3sn
- 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.)
- Granted
Links
- 150000001875 compounds Chemical class 0.000 title claims description 22
- 239000000843 powder Substances 0.000 claims abstract description 37
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 claims abstract description 32
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 16
- 229910052718 tin Inorganic materials 0.000 claims abstract description 14
- 230000004888 barrier function Effects 0.000 claims abstract description 12
- 229910017755 Cu-Sn Inorganic materials 0.000 claims abstract description 10
- 229910017927 Cu—Sn Inorganic materials 0.000 claims abstract description 10
- 229910052802 copper Inorganic materials 0.000 claims abstract description 10
- 230000000087 stabilizing effect Effects 0.000 claims abstract description 10
- 239000002253 acid Substances 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 24
- 229910000906 Bronze Inorganic materials 0.000 claims description 22
- 239000010974 bronze Substances 0.000 claims description 22
- 238000002844 melting Methods 0.000 claims description 8
- 230000008018 melting Effects 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 230000015572 biosynthetic process Effects 0.000 claims description 5
- 229910000657 niobium-tin Inorganic materials 0.000 abstract description 27
- 238000010438 heat treatment Methods 0.000 abstract description 12
- 239000000463 material Substances 0.000 abstract description 8
- 239000011248 coating agent Substances 0.000 abstract description 2
- 238000000576 coating method Methods 0.000 abstract description 2
- 238000004090 dissolution Methods 0.000 abstract description 2
- 239000010949 copper Substances 0.000 description 21
- 238000009792 diffusion process Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 6
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 5
- 239000011812 mixed powder Substances 0.000 description 5
- 229910017604 nitric acid Inorganic materials 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000011159 matrix material Substances 0.000 description 3
- 239000000155 melt Substances 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910000765 intermetallic Inorganic materials 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 235000018185 Betula X alpestris Nutrition 0.000 description 1
- 235000018212 Betula X uliginosa Nutrition 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 210000003127 knee Anatomy 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000002887 superconductor Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野コ
本発明は、化合物系超電導線とくにブロンズ法により製
造するＮｂ３Ｓｎ系化合物超電導線における安定した超
電導接続を確立できると共に、接続部の機械的強度をも
確保可能な改良された接続方法に関するものである．
［従来の技術Ｊ
化合物系超電導線には種々な戒分系のものが発表されて
いるが、実際に実用化されているものはＮｂ３Ｓｎ系あ
るいはそれにＴｉをドープして高磁界性能の向上を図っ
たものがほぼ主流を占めている。Detailed Description of the Invention [Industrial Field of Application] The present invention is capable of establishing stable superconducting connections in compound superconducting wires, particularly Nb3Sn compound superconducting wires manufactured by the bronze method, and improving the mechanical strength of the connection portions. It concerns an improved connection method that can also ensure [Conventional technology J Various types of compound-based superconducting wires have been announced, but those that are actually in practical use are Nb3Sn-based or doped with Ti to improve high-field performance. almost all of them are the mainstream.
このような超電専線がもし合金系であれば、超電導線の
露出された端部を単に溶接しさえすればよく、その接続
はまことに容易である．しかし、接続対象が、化合物系
となると甚だ厄介である．すなわち、化合物系超電導線
の超電導部分は、化合物を生成する金属元素を接触させ
拡散加熱することにより、その拡散層に所望の金属間化
合物を生成させるものであり、接続部においてもその化
合物が超電導線側と連続していなければならない．もし
その連続が途切れてしまえば、その途切れた部分は超電
導体ではなくなってしまい、超電導線としての用をなさ
なくなるからである．
Ｎｂｓ Ｓｎ系超電導線の製造方法には、表面拡散法、
ブロンズ法、インサイチュー法あるいは粉末法など様々
な提案がある．
しかし、工業的規模の量産に適用されているのは、目下
のところそのうちのブロンズ法である．このブロンズ法
は、第４図に示すように極細のＮｂフィラメント１．１
の多数本をＣｕ−Ｓｎブロンズ２のマトリックス内に埋
込み、その外周にＮｂバリア３を設け、このようにして
形成されたサブマルチ線４，４の複数をＣｕ安定化材５
の中に埋込み、Ｎｂ３Ｓｎ系超電導線６を得るものであ
る．
ここにおいて、Ｃｕ安定化材５はその文字の示す通り安
定化材としての役目を果すものであり、Ｎｂバリア３を
設けるのは、Ｃｕ−Ｓｎブロンズ側より拡散してきた元
素によりＣｕ安定化材の樺電率が低下し安定化材として
の役目が不十分とならないように、このＮｂバリア３に
よって安定化Ｃ ｕ ｍＪへの拡散を阻止するためであ
る．第４図のように構成し、これを所定の
Ｎｂ３Ｓｎ化合物の生成する温度にまで加熱してやれば
、Ｎｂフィラメント１とＣｕ−Ｓｎブロンズとの間で拡
散が生じＮｂフィラメントの界面にＮｂ３Ｓｎ化合物層
が生成され、この層が超電導特性を示す．なお、ここに
Ｃｕ−Ｓｎブロンズを使用するのは、ＣｕがＮｂとＳｎ
の反応を促進させる効果を有することも配慮する意味が
ある．このようなＮｂ３Ｓｎ系超電導線の′＃続法の従
来例としては、第３図に示すような提案がある．すなわ
ち、接続しようとする超電導線６．６−（もつとも、こ
の段階では未だ拡散加熱はされておらず正しくはＮｂ３
Ｓｎ化合物の生成前の中間製品であるが、以下この段階
をも含め超電導線と呼ぶものとする）の端部の安定化Ｃ
ｕ５，５−およびＮｂバリア３，３−ならびにサブマル
チ線のＣｕ−Ｓｎブロンズマトリックスを硝酸等で溶解
し、所定長のＮｂフィラメント１，１および１−１−を
露出させる。この露出させたＮｂフィラメント１，１お
よび１−，１−を図のように撚合せ状態として接合させ
、その上に安定化Ｃｕ５，５−の先端部分から当該撚合
せ接合部分にブロンズパイプ１０を被覆し、このブロン
ズパイプ１０とＮｂフィラメントの撚合せ接合部を共に
圧縮し、その後前述したＮｂ３Ｓｎ生成のための拡散加
熱を行ない、ブロンズパイプとＮｂフィラメントとの間
にＮｂａ Ｓｎ層の超電導化合物を生成させるものであ
る．
また、別な提案例として、上述同様にしてＮｂフィラメ
ントを露出させた後それらを互いに接合させ、これをＮ
ｂ，Ｓｎ粉末の混合物を含んだＮｂスリーブ中へ挿入し
、圧縮変形させ一体化させた後、接合部を外部から加熱
して熱処理を行ない、ＮｂフィラメントおよびＮｂスリ
ーブ内側、Ｎｂ粉末同志にＮｂ３Ｓｎ層の超電導金属間
化合物を形成し２て接続する方法も提案されている。If such a superconducting wire is made of an alloy, the exposed end of the superconducting wire may simply be welded, making the connection extremely easy. However, it becomes extremely troublesome when the connection target is a compound system. In other words, the superconducting part of the compound-based superconducting wire is made to contact a metal element that produces a compound and heat it by diffusion, thereby producing a desired intermetallic compound in the diffusion layer, and the compound also becomes superconducting at the connection part. It must be continuous with the line side. If the continuity is interrupted, the interrupted part will no longer be a superconductor and will no longer be useful as a superconducting wire. The manufacturing method of NbsSn-based superconducting wire includes surface diffusion method,
There are various proposals such as bronze method, in-situ method or powder method. However, only the bronze method is currently being applied to mass production on an industrial scale. This bronze method uses an ultra-fine Nb filament of 1.1 mm as shown in Figure 4.
are embedded in a matrix of Cu-Sn bronze 2, an Nb barrier 3 is provided around the outer periphery, and a plurality of sub-multi lines 4, 4 thus formed are embedded in a Cu stabilizing material 5.
to obtain an Nb3Sn-based superconducting wire 6. Here, the Cu stabilizing material 5 plays a role as a stabilizing material as its name indicates, and the reason for providing the Nb barrier 3 is to prevent the Cu stabilizing material from being diffused from the Cu-Sn bronze side. This is to prevent diffusion into the stabilized C u mJ by the Nb barrier 3 so that the birch conductivity does not decrease and the role of the stabilizer becomes insufficient. If the structure shown in Fig. 4 is heated to a temperature at which a predetermined Nb3Sn compound is generated, diffusion will occur between the Nb filament 1 and the Cu-Sn bronze, and an Nb3Sn compound layer will be formed at the interface of the Nb filament. This layer exhibits superconducting properties. In addition, the reason why Cu-Sn bronze is used here is that Cu is Nb and Sn.
It is also meaningful to consider that it has the effect of promoting the reaction of As a conventional example of the '# continuation method for Nb3Sn superconducting wires, there is a proposal as shown in Figure 3. In other words, the superconducting wire 6.6- (although at this stage, diffusion heating has not yet been performed and the correct name is Nb3
Stabilization of the end of a superconducting wire (this is an intermediate product before the formation of a Sn compound, but this stage will also be referred to as a superconducting wire hereinafter)
The u5,5- and Nb barriers 3,3- and the submultiline Cu-Sn bronze matrix are dissolved with nitric acid or the like to expose predetermined lengths of Nb filaments 1,1 and 1-1-. The exposed Nb filaments 1, 1 and 1-, 1- are joined in a twisted state as shown in the figure, and then a bronze pipe 10 is inserted from the tip of the stabilized Cu 5, 5- to the twisted joint part. The twisted joint of the bronze pipe 10 and the Nb filament is compressed together, and then the above-mentioned diffusion heating is performed to generate Nb3Sn, thereby forming a superconducting compound of NbaSn layer between the bronze pipe and the Nb filament. It is something that allows you to In addition, as another proposed example, after exposing the Nb filaments in the same manner as described above, they are bonded to each other, and this
b. After inserting into a Nb sleeve containing a mixture of Sn powder and compressing and deforming it to integrate, the joint is heated from the outside for heat treatment to form a Nb3Sn layer on the Nb filament, inside the Nb sleeve, and on the Nb powder. A method of forming a superconducting intermetallic compound and connecting the two has also been proposed.
［発明が解決しようとする課題］
上記した二つの既提案例のうち、前者すなわち第３図に
示したブロンズバイブ１０の被覆、圧縮だけでは、撚合
せたＮｂフィラメント１．１−の外周とブロンズバイグ
１０の接触部にのみＮｂ３Ｓｒ１形成による超電導接続
が実現されるだけであり、特性的にみて不十分なものし
か得られない６
一方、後者すなわちＮｂ，Ｓｎ粉末の混合物を含んだＮ
ｂスリーブ中でＮｂフィラメントを接触させ、圧縮変形
させて加熟する方法は、Ｎｂフィラメント同志、Ｎｂフ
ィラメントとＮｂスリーブの内開、Ｎｂ粉末同志におけ
るＮｂｓ Ｓｎ形成による超電導接続が可能となるが、
実際には、Ｎｂ３Ｓｎ生成のための熱処理による加熱の
際に、融点の低いＳｎ粉末の溶融が先に生じてしまい、
Ｎｂスリーブ内にそのための間隙ができる．このため、
Ｎｂ粉末の密着性が低下しＮｂ３Ｓｎの連続的な形成が
阻害され、必ずしも満足の行くような超電導接続は達成
されない．しかも、本方法によっては、ＮｂとＳｎの化
学量論値の割合である３７Ｗｔ％Ｓｎの採用はできない
．
本発明の目的は、上記したような従来技術の問題点を解
決し、化合物系超電導線とくにブロンズ法により製造す
るＮｂ３Ｓｎ系化合物超電導線における安定した超電導
接続を確立できる上、＃続部の機械的強度をも確保可能
な新規な化合物系超電導線の接続方法を提供しようとす
るものである．［課題を解決するための手段］
本発明は、Ｎｂ３Ｓｎ系マルチフィラメント型の超電揮
線相互を接続するに当り、先ず接続すべき超電導線の対
応する端部の安定化Ｃｕ，ＮｂバリアおよびＣｕ−Ｓｎ
ブロンズを酸等により溶解除去してＮｂフィラメントを
所定長残存露出させ、ついで露出したＮｂフィラメント
相互を撚合せて接合させ、当該撚合せたＮｂフィラメン
トをＮｂ、Ｓｎ，Ｃｕそれぞれの粉末の混合物中に挿入
すると共にその外周にＮｂスリーブを着合させ、そのよ
うにして形成した接続部をＳｎ粉末の溶融温度よりも高
い温度に加熱してＳｎ粉末が溶融した状態下で接続部を
外部より圧縮一体化し、その後接続部並びに超電導線全
体をＮｂ３Ｓｎの生或温度において加熱し、超電導線内
のＮｂフィラメントの界面および接続部にＮｂ３Ｓｎの
連続した化合物を生或させるものであり、また、上記接
続する場合に、接続すべき超電導線の対応する端部をや
や平行状態となるような傾斜面に切断し、安定化Ｃｕ，
ＮｂバリアおよびＣｕ−Ｓｎブロンズを酸等により溶解
除去してＮｂフィラメントを前記それぞれの傾斜面より
余り大きく突出しない程度の長さに露出突出させ、Ｎｂ
フィラメントを突出させた傾斜面の間にＮｂ，Ｓｎ，Ｃ
ｕそれぞれの粉末の混合物を充填すると共にその外周に
Ｎｂスリーブを着合させ、そのようにして形或した接続
部をＳｎ粉末の溶Ｍ温度よりも高い温度に加熱してＳｎ
粉末が溶融した状態下で接続部を外部より圧縮一体化し
、その後接続部並びに超電導線全体をＮｂ３Ｓｎの生成
温度において加熱し、超電導線内のＮｂフィラメントの
界面および接続部にＮｂ３Ｓｎの連続した化合物を生戊
させるものである．
［作用コ
Ｎｂフィラメントを露出させ、Ｎｂ，Ｓｎ、Ｃｕの混合
粉末と共に圧縮一体化するに当り、低温で溶融状態とな
るＳｎを先に溶融する状態にまで加熱しておき、圧縮一
体化する際にはＳｎが溶融状態下にあるようにして圧縮
一体化すれば、他の固定状態の粉末の間隙に万遍なく溶
融Ｓｎが入り込み、圧縮一体化した後にはもはや間隙は
存在しない．この状態でＮｂ３Ｓｎの拡散生成を行なわ
せれば、接続部全体には充実状態でＮｂ３Ｓｎが生成さ
れ、従来例におけるようにＳｎの溶融に伴う引けすなわ
ち空隙は発生しないから、極めて安定的に連続状態のＮ
ｂ３Ｓｎを接続部に生成させることができ、超電導接続
としての特性を格段に向上させることができる。[Problems to be Solved by the Invention] Of the two previously proposed examples described above, it is not possible to cover and compress the bronze vibrator 10 shown in FIG. A superconducting connection due to the formation of Nb3Sr1 is only achieved in the contact area of 10, which is insufficient in terms of characteristics.6 On the other hand, the latter, that is, Nb containing a mixture of Nb and Sn powders,
The method of bringing Nb filaments into contact and compressing and deforming them in a b-sleeve enables superconducting connections by forming Nb filaments together, opening the Nb filaments and Nb sleeve inward, and forming Nbs Sn between Nb powders.
In reality, during heating during heat treatment to generate Nb3Sn, Sn powder with a low melting point melts first.
A gap is created within the Nb sleeve for this purpose. For this reason,
The adhesion of the Nb powder decreases and the continuous formation of Nb3Sn is inhibited, so that a satisfactory superconducting connection is not necessarily achieved. Moreover, depending on this method, it is not possible to adopt 37 Wt%Sn, which is the stoichiometric ratio of Nb and Sn. It is an object of the present invention to solve the problems of the prior art as described above, to establish a stable superconducting connection in a compound superconducting wire, especially in an Nb3Sn compound superconducting wire manufactured by a bronze method, and to improve the mechanical strength of the connection part. The aim is to provide a new method for connecting compound-based superconducting wires that also ensures strength. [Means for Solving the Problems] In the present invention, when connecting Nb3Sn multifilament type superconducting wires, first, stabilizing Cu, Nb barrier and Cu at corresponding ends of the superconducting wires to be connected are -Sn
Bronze is dissolved and removed with an acid or the like to expose a predetermined length of Nb filaments, and then the exposed Nb filaments are twisted and bonded together, and the twisted Nb filaments are placed in a mixture of Nb, Sn, and Cu powders. At the same time as the insertion, a Nb sleeve is attached to the outer periphery of the Nb sleeve, and the connection portion thus formed is heated to a temperature higher than the melting temperature of the Sn powder, and the connection portion is compressed and integrated from the outside while the Sn powder is melted. After that, the connecting portion and the entire superconducting wire are heated at a temperature at which Nb3Sn is generated, and a continuous compound of Nb3Sn is generated at the interface of the Nb filament in the superconducting wire and the connecting portion, and in the case of the above connection. First, the corresponding ends of the superconducting wires to be connected are cut into slightly parallel inclined surfaces, and stabilized Cu,
The Nb barrier and the Cu-Sn bronze are dissolved and removed using acid or the like to expose and protrude the Nb filament to a length that does not protrude too much from the respective inclined surfaces, and the Nb
Nb, Sn, C between the inclined surfaces from which the filaments protrude
A mixture of each powder is filled, a Nb sleeve is attached to the outer periphery of the mixture, and the thus formed connection is heated to a temperature higher than the melting temperature of the Sn powder to form Sn.
The joints are compressed together from the outside while the powder is molten, and then the joints and the entire superconducting wire are heated at the Nb3Sn formation temperature to form a continuous compound of Nb3Sn at the interface of the Nb filaments in the superconducting wire and at the joints. It is something that gives birth. [Operation] When the Nb filament is exposed and compressed and integrated with the mixed powder of Nb, Sn, and Cu, Sn, which is in a molten state at low temperatures, is first heated to a state where it melts. If Sn is compressed and integrated while it is in a molten state, the molten Sn will evenly enter the gaps between the powders that are in a fixed state, and there will no longer be any gaps after the powder is compressed and integrated. If Nb3Sn is diffused and generated in this state, Nb3Sn will be generated in a full state in the entire joint, and shrinkage or voids due to melting of Sn will not occur as in the conventional example, so a continuous state can be achieved in an extremely stable manner. N
b3Sn can be generated in the connection portion, and the characteristics as a superconducting connection can be significantly improved.
［実施例］
以下に、本発明について実施例を参照し説明する．
第ｌ図は本発明に係る第１の実施例を示す説明図であり
、既に説明した符号と同一符号は実質的に同一構或を示
すものである。[Examples] The present invention will be described below with reference to Examples. FIG. 1 is an explanatory diagram showing a first embodiment of the present invention, and the same reference numerals as those already described indicate substantially the same structure.
接続すべき超電導線６，６−の安定化Ｃｕ５，５゛を硝
酸によって溶解除去する．その後にＮｂバリア３，３−
が現れるが、これは硝酸によっては溶解しないから、フ
ッ酸と硝酸を敵当量混合したフッ硝酸により一過性の溶
解を行ないＮｂバリア３，３−を除去し、その後に現れ
たＣｕ−Ｓｎブロンズマトリックスを再び硝酸で溶解除
去すれば、その後にＮｂフィラメント１．１および１１
−のみが残存する．
この残存したＮｂフィラメント１，１および１−１ １
−を適当に撚合せ接合させると共に、その外周をＮｂス
リーブで覆い、内部にＮｂ粉末７Ｓｎ粉末８、Ｃｕ粉末
９の混合粉末を充填する．この混合割合は重量バーセン
トで
Ｎｂ：Ｓｎ：Ｃｕ＝６０：３７：３
であり、ＮｂとＳｎの混合割合はＮｂ３Ｓｎの化学量論
値である，Ｃｕの３ｗｔ％は先に説明したようにＮｂ３
Ｓｎ生或熱処理時の反応促進のためである．
この状態でＳｎの溶融温度（２３２℃｝以上に加熱し、
Ｓｎのみを溶融状態とし、他は固体状態のまま、Ｎｂス
リーブ１１を外部より圧縮し、接続部全体を一体化する
．
このようにすれば低温で溶融するＳｎが他の粉末間ある
いはＮｂフィラメントないしＮｂスリーブ間に万遍なく
入り込み、空隙部は一切無くなる．このように圧縮一体
化しておいて、つぎにはＮｂ３Ｓｎの生或温度に加熱し
所要時間その温度に保持してやれば、超電導線６．６−
のＮｂフィラメントの界面近傍および接続部のＮｂとＳ
ｎの接触し合っている界面近傍にはＮｂ３Ｓｎの層が拡
散によって生或される．このＮｂ３Ｓｎ層は超電導線６
．６゛と接続部との間で連続層を形或し、超電導！１６
．６１よ超電導接続される．しかも、接続部には先の従
来例にみちれたような空隙も生ずることがなく、極めて
安定した超電導接続部を被接続超電導線６，６一間に形
成させることができる．
第２図は、本発明に係る第２の実施例を示すものであり
、特に超電導線６，６−の接続強度を十分に確保可能に
接続する別な＃続方法を示す説明図である．
本実施例においては、図にみるように接続すべき超電導
線６．６−の端部を相対応して平行な傾斜面に形成する
ところに特徴がある。The stabilized Cu5,5' of the superconducting wires 6,6- to be connected is dissolved and removed with nitric acid. After that, Nb barrier 3,3-
appears, but since it is not dissolved by nitric acid, temporary dissolution is performed with fluoronitric acid, which is a mixture of hydrofluoric acid and nitric acid in equivalent amounts, to remove the Nb barrier 3,3-, and then the Cu-Sn bronze that appears If the matrix is dissolved and removed again with nitric acid, then Nb filaments 1.1 and 11
- only remains. These remaining Nb filaments 1, 1 and 1-1 1
- are suitably twisted and joined together, and the outer periphery thereof is covered with an Nb sleeve, and the inside is filled with a mixed powder of Nb powder, Sn powder 8, and Cu powder 9. This mixing ratio is Nb:Sn:Cu=60:37:3 in terms of weight percent, and the mixing ratio of Nb and Sn is the stoichiometric value of Nb3Sn.As explained earlier, 3wt% of Cu is Nb3
This is to promote the reaction during Sn production or heat treatment. In this state, heat to the melting temperature of Sn (232°C} or higher,
The Nb sleeve 11 is compressed from the outside with only Sn in a molten state and the others in a solid state to integrate the entire connection part. In this way, Sn, which melts at low temperatures, will evenly enter between other powders or between Nb filaments or Nb sleeves, eliminating any voids. After compressing and integrating in this way, the superconducting wire 6.6-
Nb and S near the interface and connection part of the Nb filament
A layer of Nb3Sn is formed near the interface where the n atoms contact each other by diffusion. This Nb3Sn layer is the superconducting wire 6
．． A continuous layer is formed between the 6゛ and the connection part, making it superconducting! 16
．． 61 is superconductingly connected. Furthermore, no voids are generated in the connection portion as in the prior art example, and an extremely stable superconducting connection portion can be formed between the superconducting wires 6, 6 to be connected. FIG. 2 shows a second embodiment of the present invention, and is an explanatory diagram showing another method of connecting the superconducting wires 6, 6- in such a way that sufficient connection strength can be ensured. This embodiment is characterized in that the ends of the superconducting wires 6, 6- to be connected are formed into parallel inclined surfaces in correspondence with each other, as shown in the figure.
サブマルチ線４（４゛は図に現れていない）のヱッチン
グによるＮｂフィラメント１（１−は図に現れていない
）の露出工程は、上記第１図において説明した工程と変
りはない．
本実施例において相違するところは、Ｎｂフィラメント
１．１の突出し長さを余り大きくせず、従って、傾斜切
断した被接続超電導線６，６−の傾斜面間隔も余り大き
く取らずに、その間にＮｂ粉末７、Ｓｎ粉末８、Ｃｕ粉
末９の混合粉末を充填してＮｂスリーブ１１を着合した
点にある．以下は、Ｓｎの融点以上の加熱下での圧縮、
そしてＮｂ３Ｓｎ生成のための拡散加熱処理などいずれ
も第１図の場合と変りはない．
しかし、本実施例においては、超電導線６６一間が十分
に接近し、傾斜面を介して接続部と接続されているから
、長手方向の横断面において機械的性質の弱い混合粉末
の融合部を最少限とすることができ、所謂拡散圧接状態
とすることができ、接続部の機械的強度を格段に向上で
きる特徴がある．しかも、超電導接続が混合粉末によっ
て連続生成されたＮｂｓ Ｓｎ層によって達戒される点
においては第１図の場合と変りはないのである．本発明
を実施するに当っての具体的数値は下記の通りであり、
それによって本発明の所期目的を十分に発揮できること
が確認された．
第１図におけるＳｎの溶融状態下での実作業は、４５０
℃で３０分間の加熱とし、圧縮荷重は４５ｍ／閣２とし
た，加熱温度は３００℃〜５００℃程度が適当であり、
加熱温度が５００℃を越えると超電導特性が劣化する．
また、圧ｍｖｉ重は３０〜６０ｋｇ／ｒｍ２程度の範囲
では特性の変化はないが、圧縮荷重が１ ２０ｋｇ／ｍ
２を越えると線材の変形が起り好ましくない．
その後、この接続された超電導線全体を外部から６００
℃〜７００℃の温度で１００〜２００時間程度加熱して
熱処理を行ない、撚合せたＮｂフィラメントｌ．，１−
、Ｎｂスリーブ１１内部及びＮｂ７、Ｓｎ８粉末間に連
続的にＮｂ３Ｓｎ層を形成させることができ、これらと
超電導線６，６−のＮｂａ Ｓｎとは連続状態となるこ
とも確認された．
第２図の接続すべき端面を傾斜切断する例においては、
Ｎｂフィラメントを２〜１０ａｍの長さで露出するのが
適当である．その後前述の第１図の実膝例で示す加熱温
度４５０℃３０分間、圧縮荷重４５ｋｇ／ｒｍ２の条件
で圧縮することにより、斜面に露出しているＣｕ−Ｓｎ
ブロンズおよびＣｕ安定化材がそれぞれ拡散圧接による
接続状態となり、機械的強度は一段と向上する．
なお、接続部にＮｂスリーブを使用したことによりその
部分のＣｕ安定化材が欠落することになるが、それを補
うにはさらにＣｕ被覆を行なえばよいものである．また
、Ｎｂスリーブ内に入れるＮｂ，Ｓｎ，Ｃｕの粉末は、
Ｎｂ粉末の廻りに銅をコーティングし、さらにその廻り
にＳｎをコーティングする所謂複合粉末を用いることに
より一層均一な混合状態で＃続を行なうことが可能とな
る．
［発明の効果］
以上の通り、本発明に係る接続方法によれば、ブロンズ
法により製造するＮｂ３Ｓｎ系化合物超電導線における
安定した超電導接続を確立できる上、接続部の機械的強
度をも確保可能ならしめるものであり、斯業界における
本発明の有する工業上の価値は極めて大きい．The process of exposing the Nb filament 1 (1- does not appear in the figure) by etching the submulti line 4 (4' does not appear in the figure) is the same as the process explained in FIG. 1 above. The difference in this embodiment is that the protruding length of the Nb filament 1.1 is not made too large, and therefore the interval between the inclined planes of the superconducting wires 6, 6- cut at an angle is not too large, and there is a gap between them. The point is that a mixed powder of Nb powder 7, Sn powder 8, and Cu powder 9 is filled and the Nb sleeve 11 is attached. The following is compression under heating above the melting point of Sn,
The diffusion heat treatment for Nb3Sn production is the same as in the case shown in Figure 1. However, in this embodiment, since the superconducting wires 66 are sufficiently close to each other and connected to the connection part through the inclined surface, the fused part of the mixed powder with weak mechanical properties can be avoided in the longitudinal cross section. It has the feature that it can be minimized, it can be in a so-called diffusion pressure welding state, and it can significantly improve the mechanical strength of the connection part. Furthermore, there is no difference from the case shown in Fig. 1 in that the superconducting connection is achieved by the NbsSn layer continuously generated by the mixed powder. Specific numerical values for carrying out the present invention are as follows,
As a result, it was confirmed that the intended purpose of the present invention could be fully achieved. The actual work under the molten state of Sn in Fig. 1 is 450
℃ for 30 minutes, the compressive load was 45 m/kaku2, and the appropriate heating temperature was about 300℃ to 500℃.
When the heating temperature exceeds 500°C, the superconducting properties deteriorate.
In addition, there is no change in the characteristics when the pressure mvi weight is in the range of about 30 to 60 kg/rm2, but when the compressive load is 1 to 20 kg/m
If it exceeds 2, deformation of the wire will occur, which is undesirable. After that, the entire connected superconducting wire was
The twisted Nb filaments l. ,1-
It was also confirmed that an Nb3Sn layer could be formed continuously inside the Nb sleeve 11 and between the Nb7 and Sn8 powders, and that these and the NbaSn of the superconducting wires 6 and 6- were in a continuous state. In the example of cutting the end faces to be connected at an angle in Fig. 2,
It is appropriate to expose the Nb filament with a length of 2 to 10 am. Thereafter, the Cu-Sn exposed on the slope was compressed at a heating temperature of 450°C for 30 minutes and a compressive load of 45 kg/rm2 as shown in the example of the actual knee shown in Fig. 1.
Bronze and Cu stabilizing materials are connected by diffusion pressure welding, further improving mechanical strength. Note that by using the Nb sleeve at the connection part, the Cu stabilizing material in that part will be missing, but to compensate for this, it is sufficient to further coat with Cu. In addition, the Nb, Sn, and Cu powders placed in the Nb sleeve are
By using a so-called composite powder in which copper is coated around the Nb powder and Sn is further coated around the Nb powder, it becomes possible to carry out #coating in a more uniformly mixed state. [Effects of the Invention] As described above, according to the connection method of the present invention, it is possible to establish a stable superconducting connection in the Nb3Sn-based compound superconducting wire manufactured by the bronze method, and it is also possible to ensure the mechanical strength of the connection part. Therefore, the industrial value of the present invention in this industry is extremely large.
第１図は本発明に係る方法を実施している様子を示す説
明図、第２図は本発明に係る別な実施例を示す説明図、
第３図は従来例の説明図、第４図はブロンズ法による超
電導線の具体的構成を示す説明図である．
１．１−：Ｎｂフィラメント、
２−：ブロンズ、
３−：Ｎｂバリア、
４−：サブマルチ線、
５”：Ｃｕ安定化材、
６−：超電導線、
７：Ｎｂ粉末、
８：Ｓｎ粉末、
９：Ｃｕ粉末、
１１：Ｎｂスリーブ．FIG. 1 is an explanatory diagram showing how the method according to the present invention is implemented, FIG. 2 is an explanatory diagram showing another embodiment according to the present invention,
Fig. 3 is an explanatory diagram of a conventional example, and Fig. 4 is an explanatory diagram showing a specific structure of a superconducting wire by the bronze method. 1.1-: Nb filament, 2-: bronze, 3-: Nb barrier, 4-: submulti wire, 5”: Cu stabilizing material, 6-: superconducting wire, 7: Nb powder, 8: Sn powder, 9 : Cu powder, 11: Nb sleeve.
Claims (2)
相互を接続する方法であって、先ず接続すべき超電導線
の対応する端部の安定化Ｃｕ、ＮｂバリアおよびＣｕ−
Ｓｎブロンズを酸等により溶解除去してＮｂフィラメン
トを所定長残存露出させ、ついで露出したＮｂフィラメ
ント相互を撚合せて接合させ、当該撚合せたＮｂフィラ
メントをＮｂ、Ｓｎ、Ｃｕそれぞれの粉末の混合物中に
挿入すると共にその外周にＮｂスリーブを着合させ、そ
のようにして形成した接続部をＳｎ粉末の溶融温度より
も高い温度に加熱してＳｎ粉末が溶融した状態下で接続
部を外部より圧縮一体化し、その後接続部並びに超電導
線全体をＮｂ＿３Ｓｎの生成温度において加熱し、超電
導線内の Ｎｂフィラメントの界面および接続部に Ｎｂ＿３Ｓｎの連続した化合物を生成させる化合物系超
電導線の接続方法。(1) A method for connecting Nb_3Sn multifilament type superconducting wires, first of all, stabilizing Cu, Nb barrier and Cu-
The Sn bronze is dissolved and removed with an acid or the like to expose a predetermined length of the Nb filament, and then the exposed Nb filaments are twisted and bonded to each other, and the twisted Nb filament is placed in a mixture of powders of Nb, Sn, and Cu. At the same time, a Nb sleeve is attached to the outer periphery of the Nb sleeve, and the connection part thus formed is heated to a temperature higher than the melting temperature of the Sn powder, and the connection part is compressed from the outside while the Sn powder is melted. A method for connecting compound-based superconducting wires, in which the connected portion and the entire superconducting wire are heated at a Nb_3Sn generation temperature to form a continuous compound of Nb_3Sn at the interface of the Nb filament in the superconducting wire and at the connected portion.
相互を接続する方法であって、先ず接続すべき超電導線
の対応する端部をやや平行状態となるような傾斜面に切
断し、安定化Ｃｕ、ＮｂバリアおよびＣｕ−Ｓｎブロン
ズを酸等により溶解除去してＮｂフィラメントを前記そ
れぞれの傾斜面より余り大きく突出しない程度の長さに
露出突出させ、Ｎｂフィラメントを突出させた傾斜面の
間にＮｂ、Ｓｎ、 Ｃｕそれぞれの粉末の混合物を充填すると共にその外周
にＮｂスリーブを着合させ、そのようにして形成した接
続部をＳｎ粉末の溶融温度よりも高い温度に加熱してＳ
ｎ粉末が溶融した状態下で接続部を外部より圧縮一体化
し、その後接続部並びに超電導線全体を Ｎｂ＿３Ｓｎの生成温度において加熱し、超電導線内の
Ｎｂフィラメントの界面および接続部にＮｂ＿３Ｓｎの
連続した化合物を生成させる化合物系超電導線の接続方
法。(2) A method for connecting Nb_3Sn multifilament-type superconducting wires, in which the corresponding ends of the superconducting wires to be connected are first cut into inclined surfaces that are slightly parallel to each other, and the stabilized Cu, Nb The barrier and the Cu-Sn bronze are dissolved and removed using acid or the like, and the Nb filaments are exposed and protruded to a length that does not protrude too much from the respective sloped surfaces, and between the sloped surfaces from which the Nb filaments are projected, Nb, Sn , Cu, and a Nb sleeve was attached to the outer periphery of the mixture, and the thus formed connection was heated to a temperature higher than the melting temperature of the Sn powder.
The joints are compressed together from the outside in a state where the n powder is molten, and then the joints and the entire superconducting wire are heated at the Nb_3Sn formation temperature to form a continuous compound of Nb_3Sn at the interface of the Nb filaments in the superconducting wire and at the joints. A method for connecting compound-based superconducting wires that produces
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002779A JP2606393B2 (en) | 1990-01-10 | 1990-01-10 | How to connect compound superconducting wires |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002779A JP2606393B2 (en) | 1990-01-10 | 1990-01-10 | How to connect compound superconducting wires |
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| Publication Number | Publication Date |
|---|---|
| JPH03208279A true JPH03208279A (en) | 1991-09-11 |
| JP2606393B2 JP2606393B2 (en) | 1997-04-30 |
Family
ID=11538829
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002779A Expired - Lifetime JP2606393B2 (en) | 1990-01-10 | 1990-01-10 | How to connect compound superconducting wires |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5290638A (en) * | 1992-07-24 | 1994-03-01 | Massachusetts Institute Of Technology | Superconducting joint with niobium-tin |
| JPH06196241A (en) * | 1992-12-25 | 1994-07-15 | Mitsubishi Electric Corp | Connecting method for superconducting wire and superconducting wire with connection section |
| US5583319A (en) * | 1993-10-21 | 1996-12-10 | Lieurance; Dennis W. | Low resistance superconductor cable splice and splicing method |
| WO2002063060A2 (en) * | 2001-01-02 | 2002-08-15 | Composite Materials Technology, Inc. | Nb-based super conductor and method of making |
| US6543123B1 (en) | 1999-04-20 | 2003-04-08 | Composite Materials Technology, Inc. | Process for making constrained filament niobium-based superconductor composite |
| US6836955B2 (en) | 2000-03-21 | 2005-01-04 | Composite Materials Technology, Inc. | Constrained filament niobium-based superconductor composite and process of fabrication |
| US6918172B2 (en) * | 2000-03-21 | 2005-07-19 | Composite Materials Technology, Inc. | Process for manufacturing Nb3Sn superconductor |
| US7146709B2 (en) | 2000-03-21 | 2006-12-12 | Composite Materials Technology, Inc. | Process for producing superconductor |
| GB2487926A (en) * | 2011-02-08 | 2012-08-15 | Siemens Plc | Very low resistance joints between superconducting wires |
| US8858738B2 (en) | 2006-09-26 | 2014-10-14 | Composite Materials Technology, Inc. | Methods for fabrication of improved electrolytic capacitor anode |
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| JPS59141178A (en) * | 1983-02-01 | 1984-08-13 | 三菱電機株式会社 | Method of connecting superconductive wire |
| JPS6433871A (en) * | 1987-07-28 | 1989-02-03 | Toshiba Corp | Connecting method for compound superconductive cable |
-
1990
- 1990-01-10 JP JP2002779A patent/JP2606393B2/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4877789A (en) * | 1971-12-27 | 1973-10-19 | ||
| JPS59141178A (en) * | 1983-02-01 | 1984-08-13 | 三菱電機株式会社 | Method of connecting superconductive wire |
| JPS6433871A (en) * | 1987-07-28 | 1989-02-03 | Toshiba Corp | Connecting method for compound superconductive cable |
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5398398A (en) * | 1992-07-24 | 1995-03-21 | Massachusetts Institute Of Technology | Method of producing a superconducting joint with niobium-tin |
| US5290638A (en) * | 1992-07-24 | 1994-03-01 | Massachusetts Institute Of Technology | Superconducting joint with niobium-tin |
| JPH06196241A (en) * | 1992-12-25 | 1994-07-15 | Mitsubishi Electric Corp | Connecting method for superconducting wire and superconducting wire with connection section |
| US5583319A (en) * | 1993-10-21 | 1996-12-10 | Lieurance; Dennis W. | Low resistance superconductor cable splice and splicing method |
| US6543123B1 (en) | 1999-04-20 | 2003-04-08 | Composite Materials Technology, Inc. | Process for making constrained filament niobium-based superconductor composite |
| US7146709B2 (en) | 2000-03-21 | 2006-12-12 | Composite Materials Technology, Inc. | Process for producing superconductor |
| US7480978B1 (en) | 2000-03-21 | 2009-01-27 | Composite Materials Technology, Inc. | Production of electrolytic capacitors and superconductors |
| US6836955B2 (en) | 2000-03-21 | 2005-01-04 | Composite Materials Technology, Inc. | Constrained filament niobium-based superconductor composite and process of fabrication |
| US6918172B2 (en) * | 2000-03-21 | 2005-07-19 | Composite Materials Technology, Inc. | Process for manufacturing Nb3Sn superconductor |
| WO2002063060A2 (en) * | 2001-01-02 | 2002-08-15 | Composite Materials Technology, Inc. | Nb-based super conductor and method of making |
| WO2002063060A3 (en) * | 2001-01-02 | 2003-03-06 | Composite Materials Tech | Nb-based super conductor and method of making |
| US8858738B2 (en) | 2006-09-26 | 2014-10-14 | Composite Materials Technology, Inc. | Methods for fabrication of improved electrolytic capacitor anode |
| GB2487926A (en) * | 2011-02-08 | 2012-08-15 | Siemens Plc | Very low resistance joints between superconducting wires |
| GB2487926B (en) * | 2011-02-08 | 2013-06-19 | Siemens Plc | Joints with very low resistance between superconducting wires and methods for making such joints |
| US8838194B2 (en) | 2011-02-08 | 2014-09-16 | Siemens Plc | Joints with very low resistance between superconducting wires and methods for making such joints |
| US8914087B1 (en) | 2011-02-08 | 2014-12-16 | Siemens Plc | Joints with very low resistance between superconducting wires and methods for making such joints |
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| Publication number | Publication date |
|---|---|
| JP2606393B2 (en) | 1997-04-30 |
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