CA1089203A - Method for manufacturing multisection cable core with intermetallic compound-based superconducting coating - Google Patents
Method for manufacturing multisection cable core with intermetallic compound-based superconducting coatingInfo
- Publication number
- CA1089203A CA1089203A CA294,511A CA294511A CA1089203A CA 1089203 A CA1089203 A CA 1089203A CA 294511 A CA294511 A CA 294511A CA 1089203 A CA1089203 A CA 1089203A
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- Prior art keywords
- layer
- sections
- intermetallic compound
- cable core
- superconducting
- Prior art date
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N60/00—Superconducting devices
- H10N60/80—Constructional details
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- Superconductors And Manufacturing Methods Therefor (AREA)
- Manufacturing Of Electrical Connectors (AREA)
Abstract
METHOD FOR MANUFACTURING MULTISECTION CABLE
CORE WITH INTERMETALLIC COMPOUND-BASED SUPER-CONDUCTING COATING
ABSTRACT OF THE DISCLOSURE
According to the invention, a barrier layer is applied onto the ends of each core blank prior to the formation of a superconducting layer. The formation of the superconduct-ing layer is followed by a removal of the barrier layers from the core sections, whereupon the sections are welded toge-ther along the perimeter. A superconducting layer is then produces by means of diffusion in the welding zones and the adjoining end portions of the sections stripped from the bar-rier layer, The proposed method makes the strength and super-conductivity of the welded joints equal to those of the core sections.
CORE WITH INTERMETALLIC COMPOUND-BASED SUPER-CONDUCTING COATING
ABSTRACT OF THE DISCLOSURE
According to the invention, a barrier layer is applied onto the ends of each core blank prior to the formation of a superconducting layer. The formation of the superconduct-ing layer is followed by a removal of the barrier layers from the core sections, whereupon the sections are welded toge-ther along the perimeter. A superconducting layer is then produces by means of diffusion in the welding zones and the adjoining end portions of the sections stripped from the bar-rier layer, The proposed method makes the strength and super-conductivity of the welded joints equal to those of the core sections.
Description
/ -~08~2q~
Title o~ the Invention P,ETHOD ~O~ I~,IA~AC'~URING ~1U~I'IS~CTION CABLE
CORE WITH I~'~'E~l~lLTALLIC COMPOUND-BAS~'D SUPER-CONDUC~ING COA'~IN~ :
~ield o~ the Invention The present invention relates to the manu~acture Q~
superconducting cablcs and, more particularly, to a method ~or manu~acturing a multisection cable core with an inter-metallic compound-based superconducting coating.
'~he invention is chie~ly applicable to the manu~ac-ture o~ multisection core cables with an intermetalli~ com-pound-based superconductin~ coating.
Background o~ the Inventio~
'l'he reliability o~ electrical equipment incorporatin~
cable cores havin~ a superconducting coating is largely de-termined by ~he properties o~ the superconduc-ting coating at ~he places where individual sections are spliced together.
The splices between separate lengths of the cable must be superconducting and ensure the current-carrying capacity o~ the superconductor throughout the perimeter o~ the cable core. The strength o:~ the splice mu~t be commensurable with that o~ the core. It is especially di~icult to splice sec-tions o~ cores having a superconducting coating whose com-position is based on an intermetallic compound. The splicing ~.
.' '' ' ' ' ., , ,~
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is done either by ~elding or by di~usion, but in both cases the superconductivity o~ the splice is not adequate.
'~h~re is known a r~othod ~or manu~acturin,~ a a;ulti~ec~
tion c~ble core having a superconducting coatirlg based u30n an in-termetallic compound. Accordin~ to this method, en~s OL sections o~ a superconducting cable core are placed in a transition element made ~rom a mechanical powdered mix-ture o~ cornponents o~ the interrnetallic compound, whereupon the splice is subjected to pressure and heat--treated (c~.
US Patent Speci~ication No 3,523,361, Cl. 29-599, o~ 1970).
Such a splice is not sturdy enough -to withstand the thermal loads to which tho current-carrying coro oi' the ri-~ld superconductin~; cable is subjcctod. ~hc cablQ core ma-nl~Jacturing method undcr review accounts for a cable which requires special thermal compensation means. In turn, the .:~
introduction o~ such ~eat~ es accounts for a cable design which is ~ar too complica-ted. Besides, the superconductivit~J
ol such a splice is determined by the superconductinp~ junc-tion, i.e. the inter~ace betweeLl ~he end o~ the sui~ercon-ductor and transition ele~ent, which is ~ormed due to tne destruotion o~ the oxide ~ilm and di~usiorl process; it must be rerrlerl~bered in this connection that the destructio~ of the oxide film is a ra~dom ~rocess.
.. . . .
.
; . : : ,., .i .
,. ~, ` ' :, ~015~9203 ~ here is ~urther known a method ~or manu~acturing a multisection cable core with an intermetallic compound-based supercon~ucting coating, whereby a superconducting layer is L'ormed by di~usion o~ cable core blanks comprising a lay-er OL' a high-melting component o~ the :intermetallic com-pound; individual core sec-tions are then welded into a mul-tisection superconducting cable core (c~. ~rench Pa-tent No
Title o~ the Invention P,ETHOD ~O~ I~,IA~AC'~URING ~1U~I'IS~CTION CABLE
CORE WITH I~'~'E~l~lLTALLIC COMPOUND-BAS~'D SUPER-CONDUC~ING COA'~IN~ :
~ield o~ the Invention The present invention relates to the manu~acture Q~
superconducting cablcs and, more particularly, to a method ~or manu~acturing a multisection cable core with an inter-metallic compound-based superconducting coating.
'~he invention is chie~ly applicable to the manu~ac-ture o~ multisection core cables with an intermetalli~ com-pound-based superconductin~ coating.
Background o~ the Inventio~
'l'he reliability o~ electrical equipment incorporatin~
cable cores havin~ a superconducting coating is largely de-termined by ~he properties o~ the superconduc-ting coating at ~he places where individual sections are spliced together.
The splices between separate lengths of the cable must be superconducting and ensure the current-carrying capacity o~ the superconductor throughout the perimeter o~ the cable core. The strength o:~ the splice mu~t be commensurable with that o~ the core. It is especially di~icult to splice sec-tions o~ cores having a superconducting coating whose com-position is based on an intermetallic compound. The splicing ~.
.' '' ' ' ' ., , ,~
;
' 9~
is done either by ~elding or by di~usion, but in both cases the superconductivity o~ the splice is not adequate.
'~h~re is known a r~othod ~or manu~acturin,~ a a;ulti~ec~
tion c~ble core having a superconducting coatirlg based u30n an in-termetallic compound. Accordin~ to this method, en~s OL sections o~ a superconducting cable core are placed in a transition element made ~rom a mechanical powdered mix-ture o~ cornponents o~ the interrnetallic compound, whereupon the splice is subjected to pressure and heat--treated (c~.
US Patent Speci~ication No 3,523,361, Cl. 29-599, o~ 1970).
Such a splice is not sturdy enough -to withstand the thermal loads to which tho current-carrying coro oi' the ri-~ld superconductin~; cable is subjcctod. ~hc cablQ core ma-nl~Jacturing method undcr review accounts for a cable which requires special thermal compensation means. In turn, the .:~
introduction o~ such ~eat~ es accounts for a cable design which is ~ar too complica-ted. Besides, the superconductivit~J
ol such a splice is determined by the superconductinp~ junc-tion, i.e. the inter~ace betweeLl ~he end o~ the sui~ercon-ductor and transition ele~ent, which is ~ormed due to tne destruotion o~ the oxide ~ilm and di~usiorl process; it must be rerrlerl~bered in this connection that the destructio~ of the oxide film is a ra~dom ~rocess.
.. . . .
.
; . : : ,., .i .
,. ~, ` ' :, ~015~9203 ~ here is ~urther known a method ~or manu~acturing a multisection cable core with an intermetallic compound-based supercon~ucting coating, whereby a superconducting layer is L'ormed by di~usion o~ cable core blanks comprising a lay-er OL' a high-melting component o~ the :intermetallic com-pound; individual core sec-tions are then welded into a mul-tisection superconducting cable core (c~. ~rench Pa-tent No
2,192,744, Cl. HOl v 11 /00, 1974).
The method according to the above-mentioned ~rench Patent makes use of spot welding, which strongly a~fects the current-carrying ca~clty o~ the cable core. It is hard to apply this mathod to connecting sections o~ a ri~id cable having a co~xial conductor, which is due to the fact that th~ superconducting layers are arranged one opposite ano-ther in the coa~ial gap. ~urthermore, the method cannot make the strength and superconductiVity o~ the splices as good as those of the core sections ~ithout considerably increas-ing the cable diameter at the splices.
Summary of the Invention It is an object o~ the present invention to provide a met-hod for manu~acturing a multisection cable core with a superconductinæ coatinFi based upon an intermetallic com-pound, which method would make it possible to raise the cur-rent-carrying capacity o~ the cable core.
.: . .
: , . .
1~89~3 It is another object o~ the invention to improve the re-liaoility o~ splicing cable core sections together.
The invention consists in providin~ a ~ethod ~or ma-nufacturing a multisection cable core with a metallic com-pound-based superconducting coating, ~hereby a superconducting layer is ~ormed by di~usion on cable core blanks compris-ing a layer o~ a high-melting component OL the intermetal-lic compound, whereupon the core sections are welded into a raultisection superconducting core, which method is cha-racterized, according to the invention, by that a barrier layer is applied onto the ends o~ each core blank prior to producin~ the superconductin~ layer, the barrier layer bein~ re~ovod a~ter ~orming the superconducting layer, whe-reupon ind:ividual seotlon~ are welded toy~ether alon~ the perimeter, and a superconducting layer is ~ormed at the welded joints and the adjacent portions o~ the sections, ~reed ~rom the barrier layer, the superconductin~ layer bein~ produced by means o~ heat treatment and in the pre-sence o~ a low-melting component o~ the intermetallic com-pound.
It i5 expedient that while ~orming a superconduct-in~ layer on the internal sur~ace o~ the sections and prior to ~eldi~ the sections together along their perimeter, in-ser-ts of compacted powdered mixture of the components o~
:~ ' ' , .
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, ' ' '' : ' . ' ,: ' ~089~03 the intermetallic compound should be interposed between the end'faces o~ the cable core sections, and that the in-' serts should be sealed in advance by a sheath of the high-meltin~, component o~ the intermetallic compou~d.
It is pre~erable that t'ne heat treatment should be carried out in the presence o~ a metallic melt comprisin~
the low-melting component o~ the in~ermetallic compound.
~ `he proposed method ~or ma~ufacturing a multisection cable core with a superconducting coating based upon an intermetallic comp~und accounts ~or improved stren~,th and superconductivity characteristios at the places where in~
dividual core sections are welded together; the method also' makas it possible to work out a universally acceptable proc~ss ~or assemblinr~ and welding ~ogether cable oore sec-tlons oi~li~erenk types and thus improve the rellability o~ cables.
Brie~ Descrip-tion o~ the Drawings Other objects arld advantages o~ the prese~t,invention will become more apparent from the following detailed des-cription o~ a pre~erred embodiment thereof to bc read in oonjunction with the accompanyin~ drawin~;s, wherein:
Fig. 1 is a cut-away elcvation view of a di~usiorl chambcr accomodatin~ a coaxial core s~ction with a super-corlducting coatinæ, in accorda~oe with th- invention;
': , 101~9Z~)3 ~ig. 2 is a view o~ a splice area with an internal superconduc-ting coating prior to welding the sec-tions to- :
gether, in accordance with the invention, Fig. 3 is a view of a splice area wi-th an internal superconducting coatin~ after the secti.ons are welded to-gether, in accordance with the inventio~.
Detailed Description of the Invention According to the proposed method for manu~act~ing a multisection cable core with a superconductin~ coating based upon an intermetallic compound, internal and external superconductin(, layers 1 (~ig. 1) are produced by raeans o~ liquid diffusion on core blankR 2 and ~ comprising a stabilizin~ copper l~yer 4 and a layer 5 oX a hi~h-melt-ing oornponent of the il~termetallic compound.
According to the embodiment under review, the super-conductin~,r layer 1 on the blanks 2 and 3 is produGed in a dif~UsiOn chamber 6. ~ha stabilizing copper layer 4 o~
the blanks 2 and 3 is provided in advancè with diaphra~ms 7 and 8 intended to protect the layer 4 from the effects of a molten metallic alloy 9 containing a low-melting com-ponent ol the interrnetallic compound.
Prior to l'orming the superconducting layer 1, a bar-rier layer 10 is applied onto the ends of the blanks 2 and 3, . ,: '. ' ' .' , ~L08~Zl)3 which is done in an airlock sputtering chamber. ~s the super-conducting layer is being produced, the barrier la~er 10 prevents di~rusion processes in the layer 5 o~ the hi~h-mel-ting component of the interme-tallic compound. Upon a withdrawal of -the sec-tion ~rom the di~usion chamber 6, the barrier la~er 10 is removed.
'~e sections are joined together along their perimeter by using electron beam weldin~j, this operation is accom-panied by weldi~g -the copper layer 4 to the layer 5 o~ the high-melting component oE -the intermetallic compound. A molt-en metallic alloy 9 containing the low-melting component oE tne intermetalli.c compound is used to produce a super-conductinK layer at the welded joints and tho ad,joining por-tions o~ the scctions, ~reed ~rom the barrier layer. '~his process is carried out in a di~usion chamber die~erent in design from -the chamber 6.
While producing the superconduc-ting la~er 1 (~ig. 2) on the internal sur~ace of the s~ctions, but be~ore weld-ing the sections together along their perimeter, between end faces 11 o~ the sections, ~lich are provided with an-nular grooves 12, there is interposed an insert 1~ o~ a pow-dered mixture o~ ~he oomponents o~ tb~ intermetallic corn-pound. '~he insert 1~ is sealed in advance by a sheath 14 o~ the high-melting component o~ the intermetallic compound, . - .
: ., . ., ~.
,:' , : . '' : ,: . '.. .' : , ~ . : . . ' ' ~ : ...... ..
~. , ~, ' . . ':
: .: ~ ~ , . :, , .
~89Z~3 which makes it possible to joint the sections together ~ith~
out prior evacuation and ensures a homogeneous struc-ture o~ tne superconductin~ layer both within the sections and at the splices.
Accordi~g to the ambodiment under review, cold weld-in~ is primarily used to join sections along the perimeter;
cold welding produces a region 15 (~ig. ~) in which the high-melting component o~ the intermetallic compound o~
the sections and the insert 13 are fused together.
'~he tightness of the splice is improved by using elect-ron beam welding over an edge 16 o~ the sections' perimeter.
An inductor 17 is installed in the weldinp, zone'to heat ~he latte.r~ '~he heatinpj trans~orms the structure o~ l-he ma-terial o~ the inscrt 13 inbo that o~ a superconductor.
In order to ensure adequate superconductivity o~ weld-ed splices between sections with an internal arrangement ' o~ the superconduc,ting layer 1, the amount of the low-melt-ing component o~ the intermetallic compound of the insert 13 exceeds the amount required to ensure a stoichiometric composition of the superconductor of the in~ert 13, which is because part o~ the low-meltin~ component di~uses into the region 15 to ~use the superconducting layer 1 with the superconductor o~ the insert 13.
~ he proposed method ~or manu~acturing a multisection _9_ ., '~
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' -1~8g~3 cable core ~.vith a superconducting coating on the b.lsis o~
an intermetallic compound ma~es it possible ~o dispense with placin~ the cable under vacuum, while assembling a~d weld-ing its sections together; the method o~ this invention further ~alscS it possible to have welded joints whose streng-th and superconductivity characteristics are as good as those 0~ the sections. Finally, the method makes it possible to work out a universally acceptable process o~ assembling and welding together sections o~ di~ferent types o~ cables and improve the operatin~ reliability o~ cables.
The in~ention ~ill now be e~plained in ~rea-ter detail with re~erence to some examples listin~ speci~ic conditions under which the proposed method is realized, and ~;peci~ic components o~ the intermetallic compound.
~'xample 1 A barrier layer o~ tantalum (Ta) is applied onto cable core blanks 2 and ~ (~ig. 1) comprisin~ a stabilizin~ lay-er 4 of copper (Cu) and a layex 5 o~ niobium (Nb) which is -the hi~h-meltin~j component o~ the intermetallic compound (Nb3$n). Then, a superconducting layer 1 is ~ormed in a di~usio~ chamber 6 ~rom Nb3Sn by means o~ thermal treatment in the presence of a molten metallic alloy 9 o~ s-tannous bronze.
The thermal treatment is carried out under a vacuum o~
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1 D8g~03 10 4 to 10 5 o~ rnercury at a temperature o~ 650C to 800C
during 20 to 50 hours.
The superconducting layer in the welded splices bet-een sections with an internal superconduc-ting layer 1 is ~ormed by means o~ induction heatin~ o~ the welding zone and the insert 13 to a temperature o~ 650C to 8Q0C dur-ing 15 to 50 hours. The powdered mixture o~ components of the intermetallic compound comprises niobiurn (Nb) and tin ~Sn). The above-mentioned ternporature range at which the superconducting layer is ~ormad is due to the presence o~' copper (Cu) in the molten metallic alloy and the intro-duction o~ copper as po~der to the mixture o~ the components that mal~e up the material o~ the ln~ert 13. '~he sealing sh~ath 1~ o~ the in~ert 1~ i~ o~ niobium (Nb).
~xample 2 A barrier layer of tantalum (~a') is applied onto cable core blanks 2 and 3 (~ig. 1) comprising a stabilizin~ layer 4 of copper (Cu) and a layer 5 o~ vanadium (V) which is the high-melting component o~ the intermetallic compound V3Ga.
~hen, a superconducting layer 1 is ~ormed in a di~usion chamber 6 ~rorn V3Ga by means o~ thermal treatment in the presence o~ a molten metallic alloy 9 com~rising gallium (Ga).
~ he thermal treatment is carried ou-t at a temperature `:1 .
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o~ 600C to 900C during 5 to 200 hours in an inert medium.
The superconductinK la~er in the welded splices bet-ween sections with an internal superconductin~ la~er 1 is Iormed by means o~ induction heatin~ o~ the ~eldin~ zone and the insert 13 to a temperature o~ 600C to 900C during 5 .to 200 hours. The powdered mixture comprises vanadium (~) and gallium (Ga). The sheath o~ the insert 13 is o~ vana-dium (V).
- .
- - . , . . . .. . , . . .. :, . ,. : .. . . ..
.. . : , .: :
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.
The method according to the above-mentioned ~rench Patent makes use of spot welding, which strongly a~fects the current-carrying ca~clty o~ the cable core. It is hard to apply this mathod to connecting sections o~ a ri~id cable having a co~xial conductor, which is due to the fact that th~ superconducting layers are arranged one opposite ano-ther in the coa~ial gap. ~urthermore, the method cannot make the strength and superconductiVity o~ the splices as good as those of the core sections ~ithout considerably increas-ing the cable diameter at the splices.
Summary of the Invention It is an object o~ the present invention to provide a met-hod for manu~acturing a multisection cable core with a superconductinæ coatinFi based upon an intermetallic com-pound, which method would make it possible to raise the cur-rent-carrying capacity o~ the cable core.
.: . .
: , . .
1~89~3 It is another object o~ the invention to improve the re-liaoility o~ splicing cable core sections together.
The invention consists in providin~ a ~ethod ~or ma-nufacturing a multisection cable core with a metallic com-pound-based superconducting coating, ~hereby a superconducting layer is ~ormed by di~usion on cable core blanks compris-ing a layer o~ a high-melting component OL the intermetal-lic compound, whereupon the core sections are welded into a raultisection superconducting core, which method is cha-racterized, according to the invention, by that a barrier layer is applied onto the ends o~ each core blank prior to producin~ the superconductin~ layer, the barrier layer bein~ re~ovod a~ter ~orming the superconducting layer, whe-reupon ind:ividual seotlon~ are welded toy~ether alon~ the perimeter, and a superconducting layer is ~ormed at the welded joints and the adjacent portions o~ the sections, ~reed ~rom the barrier layer, the superconductin~ layer bein~ produced by means o~ heat treatment and in the pre-sence o~ a low-melting component o~ the intermetallic com-pound.
It i5 expedient that while ~orming a superconduct-in~ layer on the internal sur~ace o~ the sections and prior to ~eldi~ the sections together along their perimeter, in-ser-ts of compacted powdered mixture of the components o~
:~ ' ' , .
.- . . . . . ..
'~ ' ,.': ' :' '', :. .' ' . . .
.. .. .. .
, ' ' '' : ' . ' ,: ' ~089~03 the intermetallic compound should be interposed between the end'faces o~ the cable core sections, and that the in-' serts should be sealed in advance by a sheath of the high-meltin~, component o~ the intermetallic compou~d.
It is pre~erable that t'ne heat treatment should be carried out in the presence o~ a metallic melt comprisin~
the low-melting component o~ the in~ermetallic compound.
~ `he proposed method ~or ma~ufacturing a multisection cable core with a superconducting coating based upon an intermetallic comp~und accounts ~or improved stren~,th and superconductivity characteristios at the places where in~
dividual core sections are welded together; the method also' makas it possible to work out a universally acceptable proc~ss ~or assemblinr~ and welding ~ogether cable oore sec-tlons oi~li~erenk types and thus improve the rellability o~ cables.
Brie~ Descrip-tion o~ the Drawings Other objects arld advantages o~ the prese~t,invention will become more apparent from the following detailed des-cription o~ a pre~erred embodiment thereof to bc read in oonjunction with the accompanyin~ drawin~;s, wherein:
Fig. 1 is a cut-away elcvation view of a di~usiorl chambcr accomodatin~ a coaxial core s~ction with a super-corlducting coatinæ, in accorda~oe with th- invention;
': , 101~9Z~)3 ~ig. 2 is a view o~ a splice area with an internal superconduc-ting coating prior to welding the sec-tions to- :
gether, in accordance with the invention, Fig. 3 is a view of a splice area wi-th an internal superconducting coatin~ after the secti.ons are welded to-gether, in accordance with the inventio~.
Detailed Description of the Invention According to the proposed method for manu~act~ing a multisection cable core with a superconductin~ coating based upon an intermetallic compound, internal and external superconductin(, layers 1 (~ig. 1) are produced by raeans o~ liquid diffusion on core blankR 2 and ~ comprising a stabilizin~ copper l~yer 4 and a layer 5 oX a hi~h-melt-ing oornponent of the il~termetallic compound.
According to the embodiment under review, the super-conductin~,r layer 1 on the blanks 2 and 3 is produGed in a dif~UsiOn chamber 6. ~ha stabilizing copper layer 4 o~
the blanks 2 and 3 is provided in advancè with diaphra~ms 7 and 8 intended to protect the layer 4 from the effects of a molten metallic alloy 9 containing a low-melting com-ponent ol the interrnetallic compound.
Prior to l'orming the superconducting layer 1, a bar-rier layer 10 is applied onto the ends of the blanks 2 and 3, . ,: '. ' ' .' , ~L08~Zl)3 which is done in an airlock sputtering chamber. ~s the super-conducting layer is being produced, the barrier la~er 10 prevents di~rusion processes in the layer 5 o~ the hi~h-mel-ting component of the interme-tallic compound. Upon a withdrawal of -the sec-tion ~rom the di~usion chamber 6, the barrier la~er 10 is removed.
'~e sections are joined together along their perimeter by using electron beam weldin~j, this operation is accom-panied by weldi~g -the copper layer 4 to the layer 5 o~ the high-melting component oE -the intermetallic compound. A molt-en metallic alloy 9 containing the low-melting component oE tne intermetalli.c compound is used to produce a super-conductinK layer at the welded joints and tho ad,joining por-tions o~ the scctions, ~reed ~rom the barrier layer. '~his process is carried out in a di~usion chamber die~erent in design from -the chamber 6.
While producing the superconduc-ting la~er 1 (~ig. 2) on the internal sur~ace of the s~ctions, but be~ore weld-ing the sections together along their perimeter, between end faces 11 o~ the sections, ~lich are provided with an-nular grooves 12, there is interposed an insert 1~ o~ a pow-dered mixture o~ ~he oomponents o~ tb~ intermetallic corn-pound. '~he insert 1~ is sealed in advance by a sheath 14 o~ the high-melting component o~ the intermetallic compound, . - .
: ., . ., ~.
,:' , : . '' : ,: . '.. .' : , ~ . : . . ' ' ~ : ...... ..
~. , ~, ' . . ':
: .: ~ ~ , . :, , .
~89Z~3 which makes it possible to joint the sections together ~ith~
out prior evacuation and ensures a homogeneous struc-ture o~ tne superconductin~ layer both within the sections and at the splices.
Accordi~g to the ambodiment under review, cold weld-in~ is primarily used to join sections along the perimeter;
cold welding produces a region 15 (~ig. ~) in which the high-melting component o~ the intermetallic compound o~
the sections and the insert 13 are fused together.
'~he tightness of the splice is improved by using elect-ron beam welding over an edge 16 o~ the sections' perimeter.
An inductor 17 is installed in the weldinp, zone'to heat ~he latte.r~ '~he heatinpj trans~orms the structure o~ l-he ma-terial o~ the inscrt 13 inbo that o~ a superconductor.
In order to ensure adequate superconductivity o~ weld-ed splices between sections with an internal arrangement ' o~ the superconduc,ting layer 1, the amount of the low-melt-ing component o~ the intermetallic compound of the insert 13 exceeds the amount required to ensure a stoichiometric composition of the superconductor of the in~ert 13, which is because part o~ the low-meltin~ component di~uses into the region 15 to ~use the superconducting layer 1 with the superconductor o~ the insert 13.
~ he proposed method ~or manu~acturing a multisection _9_ ., '~
~.... . . . . . .. . . . .
,, . , , '' , . ~: :.
. , ~ ,. . .
'' ', ' ,` '' '' . . . '', ', ' " " ' ' ' ' .
' -1~8g~3 cable core ~.vith a superconducting coating on the b.lsis o~
an intermetallic compound ma~es it possible ~o dispense with placin~ the cable under vacuum, while assembling a~d weld-ing its sections together; the method o~ this invention further ~alscS it possible to have welded joints whose streng-th and superconductivity characteristics are as good as those 0~ the sections. Finally, the method makes it possible to work out a universally acceptable process o~ assembling and welding together sections o~ di~ferent types o~ cables and improve the operatin~ reliability o~ cables.
The in~ention ~ill now be e~plained in ~rea-ter detail with re~erence to some examples listin~ speci~ic conditions under which the proposed method is realized, and ~;peci~ic components o~ the intermetallic compound.
~'xample 1 A barrier layer o~ tantalum (Ta) is applied onto cable core blanks 2 and ~ (~ig. 1) comprisin~ a stabilizin~ lay-er 4 of copper (Cu) and a layex 5 o~ niobium (Nb) which is -the hi~h-meltin~j component o~ the intermetallic compound (Nb3$n). Then, a superconducting layer 1 is ~ormed in a di~usio~ chamber 6 ~rom Nb3Sn by means o~ thermal treatment in the presence of a molten metallic alloy 9 o~ s-tannous bronze.
The thermal treatment is carried out under a vacuum o~
-10- , .
.
:
, :. ~ , , :
.
~,. .. ' ' . '. :
, . , : ' :
.
,, , ' ' ,, . ,' ,' ' ' ' ~
1 D8g~03 10 4 to 10 5 o~ rnercury at a temperature o~ 650C to 800C
during 20 to 50 hours.
The superconducting layer in the welded splices bet-een sections with an internal superconduc-ting layer 1 is ~ormed by means o~ induction heatin~ o~ the welding zone and the insert 13 to a temperature o~ 650C to 8Q0C dur-ing 15 to 50 hours. The powdered mixture o~ components of the intermetallic compound comprises niobiurn (Nb) and tin ~Sn). The above-mentioned ternporature range at which the superconducting layer is ~ormad is due to the presence o~' copper (Cu) in the molten metallic alloy and the intro-duction o~ copper as po~der to the mixture o~ the components that mal~e up the material o~ the ln~ert 13. '~he sealing sh~ath 1~ o~ the in~ert 1~ i~ o~ niobium (Nb).
~xample 2 A barrier layer of tantalum (~a') is applied onto cable core blanks 2 and 3 (~ig. 1) comprising a stabilizin~ layer 4 of copper (Cu) and a layer 5 o~ vanadium (V) which is the high-melting component o~ the intermetallic compound V3Ga.
~hen, a superconducting layer 1 is ~ormed in a di~usion chamber 6 ~rorn V3Ga by means o~ thermal treatment in the presence o~ a molten metallic alloy 9 com~rising gallium (Ga).
~ he thermal treatment is carried ou-t at a temperature `:1 .
, . ~ , .
:,., . - . ~ , .
.: . . . - ,. . ' ~
.. . . .
.; , , . ; . , . :
. . ..
o~ 600C to 900C during 5 to 200 hours in an inert medium.
The superconductinK la~er in the welded splices bet-ween sections with an internal superconductin~ la~er 1 is Iormed by means o~ induction heatin~ o~ the ~eldin~ zone and the insert 13 to a temperature o~ 600C to 900C during 5 .to 200 hours. The powdered mixture comprises vanadium (~) and gallium (Ga). The sheath o~ the insert 13 is o~ vana-dium (V).
- .
- - . , . . . .. . , . . .. :, . ,. : .. . . ..
.. . : , .: :
'' ':
.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for manufacturing a multisection cable core with an intermetallic compound-based superconducting coating, comprising applying a barrier layer on to the end portions of each cable core blank over a layer of a high-melting component of the intermetallic compound; bringing the layer of high-melting component of the intermetallic compound in each cable core blank into contact with the low-melting component of the intermetallic compound and forming, by means of diffusion, a superconducting layer on said layer of a high-melting compound; removing said barrier layer from the obtained sections; welding said sections together along their perimeter; forming a superconducting layer at the welded splices and the adjoining end portions of said sections, which is done by means of thermal treatment in the presence of the low-melting component of the intermetallic compound.
2. A method as claimed in claim 1, further comprising sealing off an insert of a compacted powdered mixture of components of the intermetallic compound by means of a sheath of the high-melting component of said intermetallic compound; and interposing said insert between the end faces of the sections, while forming the superconducting layer on the internal surface of the sections.
but prior to welding the sections together.
but prior to welding the sections together.
3. A method as claimed in claim 1, wherein the thermal treatment is carried out in the presence of a molten metallic alloy comprising the low-melting component of the intermetallic compound.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SU772436394A SU714512A1 (en) | 1977-01-03 | 1977-01-03 | Method of manufacturing multi-section superconducting core |
| SU772491719A SU714513A1 (en) | 1977-06-02 | 1977-06-02 | Method of manufacturing multi-section superconducting core |
| SU2491719 | 1977-06-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1089203A true CA1089203A (en) | 1980-11-11 |
Family
ID=26665607
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA294,511A Expired CA1089203A (en) | 1977-01-03 | 1978-01-06 | Method for manufacturing multisection cable core with intermetallic compound-based superconducting coating |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5952492B2 (en) |
| CA (1) | CA1089203A (en) |
| DD (1) | DD134580A1 (en) |
| DE (1) | DE2800196C3 (en) |
| FR (1) | FR2376522A1 (en) |
| GB (1) | GB1574671A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU883981A1 (en) * | 1978-12-04 | 1981-11-23 | Государственный Научно-Исследовательский Энергетический Институт Им. Г.М.Кржижановского | Method of manufacturing multisection superconducting core on the base of intermetallic compound with internal arrangement of superconducting layer |
| DE3121213C2 (en) * | 1981-05-27 | 1983-06-01 | Gosudarstvennyj naučno-issledovatel'skij energetičeskij institut imeni G.M. Kržižanovskogo, Moskva | Process for the production of cores composed of individual lengths with a superconducting layer |
| FR2507375A1 (en) * | 1981-06-04 | 1982-12-10 | G Energet In | Stabilised superconductive tube for waveguide - has perforated zone at end covered with conductive layer by selective coating and etching |
| CN113005406B (en) * | 2021-02-23 | 2023-02-24 | 中国科学院近代物理研究所 | Preparation method of niobium-tin film |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3523361A (en) * | 1968-06-04 | 1970-08-11 | Varian Associates | Method of splicing superconductive wires |
| US3848075A (en) * | 1971-12-27 | 1974-11-12 | Varian Associates | Method for splicing compound superconductors |
| FR2192744A5 (en) * | 1972-07-13 | 1974-02-08 | Thomson Brandt | |
| US3895432A (en) * | 1973-07-04 | 1975-07-22 | Siemens Ag | Method of electrically joining together two bimetal tubular superconductors |
-
1978
- 1978-01-02 DD DD78203068A patent/DD134580A1/en unknown
- 1978-01-03 FR FR7800057A patent/FR2376522A1/en active Granted
- 1978-01-03 DE DE2800196A patent/DE2800196C3/en not_active Expired
- 1978-01-03 GB GB72/78A patent/GB1574671A/en not_active Expired
- 1978-01-04 JP JP53000102A patent/JPS5952492B2/en not_active Expired
- 1978-01-06 CA CA294,511A patent/CA1089203A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR2376522A1 (en) | 1978-07-28 |
| DD134580A1 (en) | 1979-03-07 |
| DE2800196A1 (en) | 1978-07-13 |
| JPS53104877A (en) | 1978-09-12 |
| GB1574671A (en) | 1980-09-10 |
| JPS5952492B2 (en) | 1984-12-20 |
| DE2800196C3 (en) | 1981-09-24 |
| DE2800196B2 (en) | 1980-11-13 |
| FR2376522B1 (en) | 1981-01-23 |
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