CA1324190C - Process for manufacturing a superconducting composite - Google Patents

Abstract

Abstract of the Disclosure A superconducting composite comprising a compound oxide type superconductor and an outer metal pipe on which said superconductor is supported, characterized in that (i) said outer metal pipe is made of at least one of metals selected from a group comprising gold, silver and platinum metals and their alloys or (ii) an intermediate layer made of these precious metals is interposed between the compound oxide and the metal pipe.
The composite may be form of a solid pipe or a hollow pipe having a superconducting thin layer deposited on an inner surface of the metal pipe.

Description

PROCESS FOR M~Tt~IN~3 A SUPERg~ONlDUC~NG
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~ e pre~e~ ~nve~ on ~ te~ to ~ composite h~in~ supercondu~ g prope~y a~d a proces~ fo~ facturing ths s~e. Parti~ul~1~9 it rela~e~ t~ a proce~s~ ~r m~u~c~g a ~u~n~c~i~ composi~, such a~ a wire ha~in~ hi~her and ~ itic~l ~emperat~e a~d ~ ical cur:re~
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Under~e ~upe~adu~:t~g ~ondi~io~ per~gct dl~eti~m i~
Ob~13~$d ~d no d~er~n~ ~ ~t~t~al is ob~,e~eld ~r ~11 gh~t an el~ct~ic cur~e~t of a con~t~t ~ o ~aluo i~ ~ervl3d int~ lly, ~d h~ce, ~
v~risb~ of ~ C~101~ of ~pert:tmdllCtlYIly haY~ b~0~1 prop~sed ~ ~ fleld of el0~t~c p~wer l~WmiB~ a~9 a 2flO~l for delivo~$ et~ctrlc power t l~;so ~ e ~u~c~Bu~tlYlty e~ b~ 2~ ~ e fl~ld of powe~ elcct~ic ~pplicatl~n~ ~uch as ~D pow~r ~ora~9 ~w~r tr~3mls3ion, el~tric power ~o~e~Fation or ~o lil;c; in t~o flold of t~ port~tion ~uGh ~
magIIetic lovitatio~ tr~ or m~ ally prop~llin~ ~hip~, a high ~en~tiv~ s~o~ or deltec~or~ g~r ~slng ve~r wea~; magn~t}c ~isldt microwaYe~ ~di~ult r~y or ~ e m~idical fleld ~uch a~

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~ 2 energy be~m radia~ion ulllt; i~ fleld ~f g~lence su~h as NMR or hi~h~
ener~y physics; o~ e fleld of ~usion ~wer ~ener~ion.
~ n a~ditlon ~o th~ abovemen~iollgd powe~ elec~lc applicatlons, the superconducting mate~lal~ catl be u~ed in the ~ield o~ electronlcs, for example, as a Josephson device which is ~ illdisp~able switching devi~e for realizing a high-speed computer which c~sumes veay re~uced pow~.
However, ~heir ac~llal us~e ha~Jc bee;~l re~tric~ed becwse ~he phenomenGIl of super~on~c~lvity ~ be abserYed ollly ~t ve~ low ~ryogenlc temp~rature~. ~o~g know~ ~upe~nduc~in~ materi~
group ~f mat~3rlal~ ha~ ~o-called A~15 s~ruct~re show ~ather higher Tc ~critic~l t~nperaturg ~f superco~uc~ivl~y) th~ o~ , lbu~ ~ven ~e ~op recor~ of T~ in the cas~ of l~b3~e w~i~ ~owod ~ bl~t Tc ~ould ~ot exceed 23.2 K at most. Th~s me~n~ ~t ilquld~ed h~llum ~boil~g pOi31t og 4.2K) i~ only o~o cryogerl whi~ c~n r~ zo ~uch ~e~y low tqm~erature ~ Tc3 H~weY~9 h~i~n is not vnly ~ 8d co~$1y re~ource but also regui~ a la~ge~ed sy~t~m ~r liqueP~o~O ~erofo~e, there h~d lbeen a ~tro~g ~n~d ~or ~no~er o~e~co~duc~ag mat~rlals h~ving hi~her Tc. But ~o ~e:~al whi~h e~ceccl~d ~a~ a~v~o~ti~ned Tc had beon ~und ~o~ ~li studle~ ~or thg p~t te~ y~.
It ha~ b~n krlown ~t c~ain ce~u~icg m~teri~l of compourld oxide~ ~2dhibl~ pr~r~3r of ~u~rco~d~iYity- For egample9 U. S.
pa~e~ Noi ~932,315 di~clo~e~ Ba~PbBi t~p~ corrlpwnd o~ide which show3 ~p$rc~n~ctivi~r ~d J~p~o~e p~ent lald ~p~n ~o~ 60~173~88S
di~clos~ t B~Bi typo ~mpou~d ~xlde~ o ~how supe~co~duc~iYity.
0 ~G ~uperc~nduc~, hnw~verg pOB8e~ ather 1OW~r ~ansltion t~mpor~ture of ab~t 10 K ~d hence u~g~ of ll~ldlzed helium ~iling polnt of 4.2 K) as cry~en Is l~ abl~ t~ r~#l~æ~ ~up~o:ndu~iviol;y.
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Possibili~ of exis~ence ~f a new ~ of superconduc~ing ~te~lals havi~ mucl~ ;r Tc wa~ re~aled by Bednorz ~nd M~ller who di~covered a Ilew o~ide type ~uperconductor in 1986 ~i~, Phys. I364 ~19~ 9~
~ is new o~ide type super~on~uct~rlg ma~e~ La, ~a~ uO~ or [La, S~CuO~ whlch are called as ~he K~Ni~4-l;ype oxide h~ving ~
crystal st~uctur~ which i9 ~imil~r to lmown perov31~te type oxl~ e K2Ni~4-type ~xid~s ~h~w ~uch hig~r T~ ~ 30 K wh~h ~e ex~rem~ly hlgher th~n the ~wn ~uperconduct~g m~ ls a~d h~ce i~ be~omes possibl~ to u~e liquidi~d hydroge~ (b.p. ~ ~0.4 K) o~ ll~idiz~d neo (b.p. ~ 27.3 K) a~ ~ cryog~n wh~ch brin~ ~h~m ~o exhibit tlle ~uperconduc~ivi~
~ was ~l~o r~po~ed in ~he nwv~ parer ~hat G W. C }lU ~t al discovered in ~he Uni~d S~a~e~ of A22l~ric~ ~nothe~ t~p~ o f superconductl~lg ~ al h~v~g the criti~al t~np~a~ur~ of ~n the or~er of ~0 K 1~ ~ebnl~ry 1987l u~d hen~ po~s~bility of ~ P~ce of hi~
t~mperaturc supo~onduc~ urst ~n ~ scen~ :
~ 3[ow~Y~, ~e ~ g ~ ed n~w ~I)e su~e~o~ductin~ m~ B
whi~h was ju~t bom h~e ~ee~ s~ d ~d develG~ed only it ~ ~ og ~int~r~d bodies ~ a bu~ p~o~uced from po~Nder~ b~ ha~r~ not beefl tried :~
to b~ sh~ped into a w~ ~o~. 1~ ro~so~ is th~t ~ w type 5upe~con~uGtor~ ~ ~e~ic m~te~al~ of ~o~npolJnd o~ which do n~
posse~ e810u8h pl~ti~i~y 3r ~,an al~ bo work~d ~lly in c~parl~on with well-~ Yn metal ~pe sup~on~ m~t~l~ls suc~ a~ Ni-Ti ~lloy, axld ~:
~he~efore ~y c~ llo~ or ~e d~flcult to be shaped ~ defo~n~d into a~
e~oll~ated a~clo ~u~h ~ ~ w~ by ~ollven~lo~al tecl~ique ~u~h ~s w~c~
~wi~g ~e~hnlque ~ whi~ supo~nduc~g ~tal is ~wn di~ectly or In ~mbeddedl ~onditi~n In copper in~ a w~e ~.
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Still more, the ~bwe me~ti~ned ~intered ce~nie mate~al~9 must be sh~ped in~o ~n elollga~ed st~u~ure when ~hey ~r~ u~d ~s a sup~rcon~cting wir~ ~n practice. How~v~r, ~he above m~ntloned ~uper~onduc~ng ma~erials ob~aLned in ~ ~o~m of ~ ~inte~d body are ~
fragile and ~re apt to b~ broken or cracked unde~ ~ren Yery we~k me~hanle~l s~ress. And h~tlce, when they ~re ~haped i~o ~ wirel special ~t~ntion ~nus~ be paid ~or ~eir bandling in ord~r n~t to be broken.
It ~s proposed 1~ J~ane~e pat~ id~en No. 61~131 j307 a m~th4d for m~ufac~uring ~ supercon~uctirl~ wl~e ~m ~ metal type s~e~onducting ma~ l whl~ 1~ ~p~ to b~ o~d~zed ~nd veIy fr~ile ~l~ch a~ PbMoo 3sS~ compr~sing ~h~g~g ~e materl~ m~ wde~ 1~ a ~netal ~hell, ~udin~ m~tal shell ~Illed wi~h ~hc m~terial powder a~ ~
~emper~ture of higher th~ 1,000 C, ~nd tholl drawln~ th~ ~xtruded compo~lte. T~i~ metal wo~ chr~, howeYçr~ ~an ~o~ apply dire~tly to c~mic ma~erl~l co~sl~ting ~f c~mpound o~l~e, becau6c the compo~d oxide type s~erconductin~ material~ can not e~hibit the superco~u~iYi~ if not l~C ~peciiFl~d or p~dlo~G~ ed cry~ t~turo l~ ~
r0aliz~d, In o~er WO~I~B9 æ super~onduct1~g wiro ~hi~ show~ higbe~
crltical tomper~h~re ~n~ hlgho~ cri~ l currsnt dlo~it~ nd which is ;i use~b1~ c~ual a~li~ati~ns c~ n~t ~ obtai~d ou~ido p~le~f~rrniD~d pti~ C~ dlt~0n!~e ~ p~icular9i~ ~ie shelli~ot~i}~fnDmpr~pe~
m~$~i~lse ~o ~ n~ compounid oxi~ will b~ ~duice~ due t~ ch~nical .. r~a~tion with t~o metal of ~o ~holl, r~ultl~ poor or i~ferior i p~ope~ie~ ondu~ivi~.
Il A poly~ystal ha~ring complstely unl~o~n c~y~t~l stru~ c~i nat ;1 be obtal~ed ~r~m p~t,lcle~ h~vin~ ~upor~ond~cting pnoper~i~s alone. S~i11 m~re, ths phenom~tlorl o~ ~laperco2lduc~ apt to b~ ily b~ken in st~ngor a~agnetlc f{¢ld ~?id lmde~ ~o fluctui~io~ o~ unhomo~eneou~

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dis~ibutio~ of ~empera~ure in the s~a~.e~e~ body as well ~s ~he abovemetltloned oxide type s~perconduc~ing materi~ls po~e~6 rather higher ~peclflc resist~ce and lo~v~r h~-co~ctiYity above lthe ~ltical temperatu~e. Ther~rg, if ~he phenomeno~ of super~onduc~ivi~y bre~ks locally, ~he sin~red body prQ6iUCe~ Jo~le hea~ caused by t~
~upercondu~lng curre~t pre~erved ~e~e~ and explo~iv~ evaporation of cryogen is In~uced when the h~ated po~ion of th~ ~d body conta ts w~ e cry~gen. I~ order ~o a~e~ er, in co~lven~ional met~l t~pe ~upercon~ucting m~t~ial, superc~nd~c~ing metal is shap~d n a ~o~n of a flno wire or filame~t ~ plur~ligy of whic~ are embedded in ele~troconduc~ivo, m~l which play ~ ~11 of a by-p~s of elec~Ac curre~t when superc~nductî~iey br~
~ e ~de ~pe superc~n~ct~ng ~eri~ls ~re, howe~erl d~ffl~ulS ~o be sh~p~d or d~f~ed ~to ~u~ fll~ents, ~sus~ th~y h~ not e~ough pla~ici~ or proce~bili~ 1~ compui~on wi~h w~llo~o~ll met~l type s~duotin~ m~t~l~ ~ch ~ Ni~Ti ~lloy.
Itl o~der to realiz~ a ~oli~ble ~d pr~ctical ~ condu~ti~
~ructure, it 1~ pe~s~l~ ~hat ~e ~ pt3~B~ ~CIUgh ~ l$th ~nd tenaci~y whi~h is ~u~ficie~ to ~du~ b~ding ~o~e du~g u~a~e ~nd al~o ~a~ a~ fl~cr cro~ nal dimen~io~ ~ po~iblo ~ ~uch m~er ~t c~ transmlt curre~cy at hi8her crl~cal cu~T~s d~ty and ~ h~
~ritlcal ~empeEatur~. How~Yer, con~ntlon~ t~ni~es ~n not ~ are dlf~lcult to pr~du~ wi~ ~ed ~e~c a~icl~s lpo~se~ing ~atlsf~ctory me~ical ~en~ and t~aci~ well ~s ~ 3her dim~n~ion~l ratio of le~g~ 0~8 ~
Taki~ ~e ~Ibwf~l~f~l~io~lfe d ~ lon lnto c~nsidf~rat~o~, ~he pre~ent Lventor~f ha~re pt~po~;ed pl~Of~:SSeS l~fpr p~f~~ g ~ntered cer~mif~ e~
haYi~g ~ p~t~c~lly u~able h~gho~ d~naerlsifsn~ll F~io fO~ len8th to fCrO~I~

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section without using organic binder which is a cause of deterioration of strength and tenacity in Canadian patent application serial No. 558,142 titled ~Process for manufacturing a superconducting wire of compound oxide-type ceramic~ and serial No. 560,056 titled "Process for manufacturing a compound oxide-type superconducting wire" in which a me~al pipe filled wi~h material powd~r is subjected to plastic deformation such as wire-drawiny technique by means of a die and then is sintered.
These solutions are themselves satisfactory but the present inventors has continued to develop another process which can produce a ceramic wire possessiny higher strength ~nd no breakage and complete the present invention.
Thereforel an object of the present invention is to overcome the above mentioned problems of the conventional technique and to provide an impro~ed process for producing a superconducting wire like composite which has a higher Tc and higher stability as supercon~uctor which can be applicable to practical us~s. -Summary of the_Invention The present invention pro~ides a wire-like composite comprising a compound oxide type ~uperconductor and an outer metal pipe on which said superconductor is supported, characterized in that a layer composed of at least one of precious metals select~d from a group comprising gold, silver and platinum metals ~nd their alloys is interposed at an interface between the compound oxide type superconductor and khe outer metal pipe.
More precisely, according to the present invention, the wire-like composite including a compound oxide type superconductor and an outer 'A

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metal pipe on whleh said sup~rco~a~c~r i~ 3u~o~t~d is char~e~ixed ~n that id outs~ me~al pip~ is m~de of ~ as~ on of met~l~ s~le~ted ~m a 8~ compr~slng g~ld, silver alld pl~tirlaa~ metals and ~ei~ alloy~, or (ii~ an hltennedi~t~ r compos~d taf a~ on s3f me~ e~e~ed ~om a g~up comp~ gold~ sil~er ~d plati~ et~ and lloy~ nterposed be~wee~ ~id co~ound ox~de ~7pe superconduc~r and s~id outer m~tal pipe.
Nc~w, e~ch ~f ~e case~ ~d ~ will be described in more in d~t~
~a~e I ~

I~ casle~ the outer m~al pipe i~ m~d~ of A~ or plabnum ~l~e~nt~ of P~ u~ 0~ ~ t~e~ all~y~ ~nd s~u~d$ ~ ~Yers a ~i~ersd bo~y of corzlpound a~it~.
~ c~rd~ to ~ embodimen~, the ~ rco~uckor i8 eom~ac~d In olJte~ me~l plpo ma~ af pr@ciou~ mot~.ls ~ving ~ l~wer ~lect~cal re~i~t~e~ a high~r ~peciflc h~t ~d ~ hi~e~ heat ~nduct~ , BO ~h~t ult~ng ~olid wi~l~o e~mpo~i~o ~haw~ high~ mech~ical ~eng~h ` ~ be~u~e ~ ~g~le s~ed ~cle i~ ~ppor~gcl by a me~llic ~heath ~aYing ~3 ~el~ ly hi~er ~ren8~ ~d ~ ci~ ~an ~e ~tored ~icle.
St~ll mo~ ord~ go the pra~G~ UlWnti3Il~ oxyg~n c~ntcnts tn the s~erconduct~g s~r~d body c~3n be ~tabillzed be~au~ of the p~es~Ilce of ~he ou~ m~al p~pe. In fi~ t9 ~e c~ 5n co~tent~ of ~o bov~me~tlur~ed &os~po~d oxidGs ~uoh ~ an oxld~ ~02~air~ng ~ IIa `3 ~lenlen~ ~d a IIIa ~l~men~ whi~ can b~ ~s~ ~dvantageou~ly in the ~, pr~ in~nt1on m~ v~y or chan~e if they ~o~ta~t ~tre~itly wilh a metal :~1 .7~
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which is 11~ to b~ ~xld~zed. To ~ol~T~ t]hlæ problem, according ~o ihe pre~nt in~tio~, ~e ou~ m~al pipe i6 mad~ og at le~s~ otle of p~ OU5 metals sele~ted ~om ~old~ ~ilver, platimlm met~l~ or their alloy~ t~
e~close the oxid~ there~n so tha~ variation ~f ~23rgell conten~ m ~he compou~d o~ide i~ ~uppre~sed.
An irmer ~u~ce of ~e m~tal pip~ ma~ ~ua~er h~ve ~ prote~tiv~
layer which ~e~ist~ to ox~dation so ~a~ oxy~en content~ in the , comp~u~d o~e i~ m~in~ai~ed w~ ~g~ p~teC~iY~
l~yer may be made of ~a oxide such a~ A~ produced ~ ~x~diz~~ he ~ner ~ ce of th~ m~tal pip~.
~ outer m~al plpe may h~f3 pe~fo~atior~ ~r ~h holes which make ~ p~t og thc ~upe~nductor op~ a~o~pher~. To re~lize ~u~h s~ructur~ sutcr m~l plpe may be ~a~ of a cyl~dr~al wire ngt~i~8 ~rroundi~g tl~htly ~ olld sup~r~onduc~or.
A m~l wire or wi~os may b~ os~b~ddgd in ~hc ~upe~on~uc~or.
e wi~ ~ preferably ~u~fa~ ed wl~ enal wh~ Is ~e~ or ~ac~ive with ~p~t ~o ~ ~u~r~llductor, T~e ~ol~d co~npo~lt0 ~boY~ti~ ~o~cGd by a ~occss ac64rdlnR ~o tho pre~t ~nY~ti~ char~c~e~2~ by ~h~ B~ep~ c~mpri~
p~eparing ~ lea~t ~n~ of ~at~r~al p~wd~rs ~ele~od ~rom a ~xoup ~ompr;s~n~
~i) a powd~ ~ixh~ of c~ ach c~n~in~g at loast Oll~ of ~rs~t ~le~ n~ ~d ~i~
(ii~ ed p~wder ~ ~ompQu~d o~de pr~p~ by sint~ g ~e pawd~r m~gtur~ of (i~ and ~en by pulv0~ng ob~ined s~t~r~d ~ . body~
compac~ing the mat~l p~wd~r ~n a metal p~p~ mads of ~ st on of me~ls ~el~d from a gro~ c~mp~8~ng gold, silver ~nd plati~um ~notal~

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and ~eir alloys, and then head~g ~he me~al pipe flll~d wl~ the m~;er~l powder at ~ tempGr~u~ ranging be~ween ~ uppe;r limi~ con~sp~nd~n~3 ~u the lowest melting pO~Ilt of any on~ of con~tltuent components in the m~terial p~wder ~d ~ lower l~mit which i6 lower by 1~ C ~han s~id `t upper l~t to sin~e~ sa~d materî~ wcle~ inslde ~he ou~r me~l pipe.
Each of the co~p~ ds may b~ ~ o:~ide pow~er D~ ~1 c~bonlat~
powde~ of co~stih~en~ elemen~s of ~aid compound o~l~. ~ atomic ratio of elemen~ ld malte~ial powders m~y be ~u~ed ~ ~e gnme v~lu~ a~
an atomic ~tio of const~t~aent element~ ~n s~id co~pound oxid~ to be produeed.
The mat~ powder may be compa~ted under ~ p~es~od ~ndi~on and/or may be ~r~ulat~d p~evioudy~
Wi~e-drawin~ may be pe~o~ed duriIIg or af~r th~ s3~ter~ng opera~lo~. It i~ o po~1bl~ ~o ~at~tre~t ~ ~t~r~d p~odu~t at a t~mpe~ in~ ~rom 160 ~ ~o 7~ ~C. Ih~ ea~ne~t may be d out ~te~I~ wiro-drau~ng but b~o~ ~o ~int~rlng opera~i~n.
'1 Gene~lly ~ ~tcrin~ of tho ~erl~l powder m~y be c~ed out at a temp~rature ra~gin~ f~m 500 ~C ~o 1,200.C ~ which me~l o~de J ~uch a~ A~ i~ d~compo~d to A~ and ~g~ll whi~ do no~ reduco ~he ;1 con~pound oxid~.~o ~t tho oxy~en GOn~lt~ In ~he o~ide c~ be m int~n~d ~ a const~nt Y~ue whl~ il~ b~neflci~ c~y~tal ~tructu~e ~ndl~ o~yg~ d~flcierl~y of ~p~ior ~upo~o~ductor of compound ~J o~ideg.

~: A 3~110w com~o~lt~ comp~isoa ~ outer me~l pipo made of Ag, Au or pl~l;n~ ol~ ~ Pd, P~, Rh, i~7 Ru~ r ~ alloy~ ~t a la~r ;', of compo~d o~ide ~ upercon~ctor ~pplied ~r d~o~ited on ~ er sur~aGe of ~18 metal pi~.

,-`,~ ~ .' ,1 ' The layer of compound oxide! type superconductor may be preferably deposited by sputtering technique on an inner surface of the metal pipe.
The outer metal pipe may be closed at opposite ends thereof and/or may be filled w:ith inert gas. It is also possible to circulate a coolant through the interior of the hollow pipe.
It is also possible to reduce a cross section o~ the metal pipe by wlre-drawing to ob~ain a finer pipe after the layer of compound oxide type supexconduc~or is formed on the inner surface of the metal pipe.
~', It is also pos~ible to ~orm an additional inner ~ protective layer consisting of a material which have lower i, coefficien~ of thermal expansion on the superconducting compound oxide layer supported on the inner surface of the ~, metal pipe. The material having lower coefficient of thermal J, expansion may be Si, zirconium, SiOz or glass.
;~¦ The layer of superconductor may be formed also by wet-~? coating technique including application or coating of a thin film layer of superconducting material containing an organic binder on the inner surface followed by sintering thereof.

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Case II - An intermediate layer made of precious_metals is i~terposed between_ the outer metal pipe and ~he , superconductor II-I) A hollo~ composite In this case, the ou~er metal pipe may be made of any ~3 metal such a~copper~ iron ox the like but an intermediate layer m~de of precious metals is interposed between the outer metal pipe and the superconductor. -~
The intermediate layer may be made of Ag, Au, Pdt Pt, Rh i Ix, Ru, Os or their alloys. The metals such as Pt, Au or the like which possess relatively lower free energy (~G) for producing their oxides deposited on 1 ' .

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'; "' ' ' ' ' " ' ' ' ' ' . .` " ' ' ' ' ,' " '~ , ' . ' ` ' " . ". ~"; ' ' ,. ' ' ~e ~ner surface of the metal plpe pr~t c~oltlic~l re~ction behveen ~he metal pipe wi~h ~he compoulld oxide to pr~e~ve a cons~ compositi~n of ~he supe~onduc~o~. This interme~i~te layer may Ibe pr~du~ed by any ~mown technique such ~s vacuu2n~d~0sl~ion, ~put~ln~, pla~ing~ ~oatirl~
or claddi~ ech~lque in whidl a p~iou8 metal pipe is lilled on ~e inner su~ace of the outer me~al p~
The com~oulld ~îd~ ~ supg~o~cluc~r ma~r be ~n a fo~m of ~
lay~r d~poslted ~n ~ ~er sur~ace of thB l~rmedia~ iay~ d~posited by sputtering technique or by wet co~t~n~ te~nl~ue ~ollowed by sin~er~ng op~ion on an irmer ~e o~ ~id metal pi~.
ner sur~ce o~ said lnt~nedi~e la~er may b~ ~unhor co~ted wi~ ~other ~p~or~n~ lay~ m~ds of on~ of m~to~ w~ich h~ s~ong adhe~t~e pr~er~y to s~id c~mpound ~xide t~ supo~oltdu~tor, wh~c~ ls ~t~bl~ to said ~o~npourld o~lde ~pe ~or~o~ductor~ Of whi~h ~a~
rela~lYoly lower the~m~l e~ion ~o~ nt wl~ re~pect ~o the compound o~ide ~ uper~ond~ctor ~uch ~ Si, z~r~o~ium, SiO~ or thi3 case9 the compou~d o~ide ~ uperconductor is ~n ~
of ~ t~r@d ~lit ~ a~t~d ~nsid~ diat~ l~yer depo~ited on thc i2~nor sur~$ of the outo~ m~t~l plp~ a~ordi~ to th~ ~
~bov~n~nti~tled method tII-l~. The ~olid m~ co~paGted ~ ~e me~al pipo ~y ~ pro~d b~ the ~me pr~edu~ ~ Clol~.
Now, ~o pre~en~ i~v~n~io~ wlll b~ d~cribod wi~ re~enGe ~o ~t~c~d dr~wln~s whi~h illustra~o pz~fe~ed emb~lmGntB of the pre~nt ~VO~lOfl bu~ ~e n~ l~tat~re of ~o p~es~ en~.

PI~ 1 ie an ~ ratlve ~ s se~ al Ylew of ~ ~ol~d compo~lte ~ccordlng to ~e pr~t i~rentiorl~ :
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FIG. 2 is ~n illustratiYe G~OSS ~es~tion~l view whi~h is similar ~o FIG. 1 and whlch ~hows anotiher ~mbod}~en~ of ~ soli~ composi~e accor~ to the pre~ invelltion.
FIG. 3A and 3B lllu~trate ~wo var~tlorls of the ~olld ~omposi~e sh~ IG.~.
FI~. 4A ~d 4~ tra~e ~other embodimerl~ of ~ composi~e according to ~e pre~en~ inYentlon~ wh~r~ FIG~ 4A 1~ a cross ~eGtiC3Il ~hereof and PIG. 4B sh~ws a side ele~lotl ~he~eof.
FI~. 5A ~d SB illus~rate a ~a~ion of the com~osite shown in FIG. 4, whereîn P~ is a c~os~ sectton ~ereof ~d FX~. SB show~ a side elevatlo~ ~her~oL
P:l~. 6A a~Ld 613 il~u~trat0 s~ill a~o~ embod~t 9f ~he present ~nY~nt~, whexeibrlt ~TG. 6A ~ a ~ sec~ therwf and PI~. ~E3 is a per~cti~e YigW th~oP.
~ I~3. 7, 8 Qa~d 9 ar~ cro~s se,~tlo~al vlow~ o~ still ~other embod~nts of compo~ites ~c~or~ to th~ p~s~n~ l~Yen~ion.
. lO is ~ c~s~ cti~ of a ~aoll~w ~Ot~pOB~ acco~d~tlg ~o l;h8 p~ent ~ t~f;~ o . 11 is ~n ~llu~tr~t~o vi~w Of ~ ~h~p~U~ whioh Cllt~ bo uscd or m~nu~ ring ~o~at~uoia~ly ~ composite h~ a t~pe-like ', c~ on ~ccord~g to ~ho pre~t i~ention.

~ q~0~2ng to Pl ~3. 1 whiGh ~llu~as a ~yplc~ c~ po~lte ~ccor~din~
'tO the pre~ent in~o~io~, the compos~to ~ho~ FI~
superco~duc~i~g soild rolmd wire c~pri~jng a core of a sin~ed ;(J c~mpouIld oxi~ l l ~d an ou~er m~t~ p~e 12 made og preciou~ m~
su~dn a~ ~ilYer or pl~ urrolmdlTIg Itigb~ly ~e ~Intcred compoulld .
~ 12 ,~

.. ., . ;, , ~ , ,, ;,, , .,., .. , : .. ,. . " :, . .. . ;.

- - \
~ 3~i q~3~
oxide 11. In the follo~ing ~escAp~on, pla~ m ls used ~ a mea~erial of the me~al p~pe but is only ~ ex~nple of the m~erl~l of ~e outer p~pe.
FIG. 2 illustrate~ a~other e~bodi~n~t of a ~omposi$e which i~
simllar to ~IG. 1 bllt a l~er ~f P~O 23 is iII~e~po~ed be~ween ~n o~er pipe ~2 ~d a sinte~ed ma~s of c~mpo~d o~i~ 21 compacted ~n :he Pt pipe 22. The PtO l~yer 23 can be p~oduced previou~ly by heatm~ an inner ~ ce ~f lthe Pt pipe 22 in air and will ~upply oxyggn prodll~ed by therrnal decomposltion thereof ~t th~ follow~ng ~in~e~g ~age to ths perconduc~mg ~a~erial fllled therein to con~rol the ~s~gen c~nt~ts of ~hs sinterod co~npound ~dde ~o ~ ~r~per v~lue.
~ rwo ~ariation~ $~own i~ F'I~. 3A ~d 3~ illw~e a ~c~gul~r sup~rconducgin$ wir~ or rod ~nd ~ fl~ tape liko ~up~rconduc~or a~co~din~ ~o th~ re~l~n, ~a tbu~ v~a~ intere~ mas~
31a ~nd 311P i~ enclQsed h ~ outer Pt pip~ 32~ ~ ~ a pl~tinum l~and 32b t~rough an int~ Ge l~yer of PtC) 33~ ~nd 33b. Th~ ~mpo~l~e of ~G.
3A m~y be protuc~d by de~orm~n~, a ~ound pi~o or by using a ~e~t~ngall~r pipo or ~n be m~h~rcd by a pro6~ss ~cllldlll~ step~ of nloldi~ ~ect~nguîar sup~ondu~or and ~ c~re~ e xliol~d arti~l~
W~ a me~
~ othBr ombod~ of a compo~it~ ~ccordin~ to the pre~n~
1WI1t14TI ~hOWal ~n FI~. 4A ~nd BB i~ similar to the co~si~ ~f ~I(3. 1, bu~ ~10 OU~&~ pipg: ~2 has pe~for~t~n~ gh-hole~ 44 whlc~ ma~e tho i~n~r ~ore 41 ~o~et to ~u~rou~di~ . SA snd ~G. ~B
lllu6~ate ~ v~la~i~n of a co~po~ite ~h~wn m ~G. 4~ The compos~e of F~G. 5 has ~ ~t~n~ular croæ~ s~ n. ~ ~ill ~o~er ~b~di~n~nt show m FI~3. 6,, ~e ou~sr m~al plp~ 5hOlYII in ~I~c 1 ~ digpla~d by ~ wlre n~ 2 ~ich etlYelopos ~ ism~r ~r~ of s~er~d GOm~Und o~i~ 61.
In ~e ~bod~ments of ~. 4 to C, ~e co~ of cotnpolsnd oxides 41, 51 ~1S ' I

i ` "' ' , ~ ' , ' ,' ' " ' ' ' ' . ' , ,. , ',' ~ ' ' ' ' ' ; ' ' ' . . ' ' ' " ' ' ,~ . ' ~' ,." ' ': '~ ,., ' . ' . ' ' '' ' . . ' ' ' , ' ' 1, '~' '' .. ' ' '., '. ' ' ' ',.' ' ," . ' : .,, ' : ,~,',, , " , and 61 c~n con~a~t direct~ wl~ mo~phere ~o pg~t ~ ~cili~at~ t~e colltrol of oxy~ con~ents in the sin~e~ed compouIId oxide durin~
s~nter~rl~ stage.
FI~3. 79 ~ a~d 9 show t~ee variatioll~ of ~olid comp~ite acco~l~g to ~he presene lnventlon. In these e1nbod1ments, a plur~ of pla~inum wires 84, ~4 and 1~4 ~ embedd~d i~ a c~e of ~omp~und oxld~ type superconduct~ ~1, 91 ~d 101 whi~b Is surr0lJnded b~ an outer platin~
plpe 82~ 92 or ~ out~r pl~t~um barld 102. ~ ~ emb~dlmen~s ~hown, an ~ide l~er of Pt~ 83, 93 ~d 103 is i~t~posed ~ an ~n~e~ce b~ween ~he ~ore 81t 91 and 101 ~nd the out~r shea~h 82, 92 ~n~ 102. l[~e oxide lay~r 83, 93 ~nd 103 ca~ be produced ~sily by ~eat~g in a~r ~n 3~er ~c~ o~ the ou~er ~h~ath 82, 92 ~nd 102 to o~1dko tho ~amc. l:he e~t~ncs of ~e oxid~ l~yer 83~ 93 ~d 103 i~ p~e~e~bl~ to pr~e~t th~
oxygen conten~ hc ~nte~ed compound ~a~ide ~ tn~ lueneed ~y chomical ~a~o~ w~ ma~ri~l of ~ pl~.
llle ~omposite ~hown i~ . 8 i~ 6~ r to ~hat of PI(3. 7, but ! cont~ s a 1~rger n~b~r ~d/or ~lcker p1~tilnum wi~e~ ~4 i~ the A~ sup~on~c~ng com~und o~de cor3 ~ if ~u~o~duc~ y Is b~kgn accidentally, a very hl~h int~s~ty of e1ectric ~rent must be passed by ~rou~ ~e ordin~ry c~ductor~ connpo~d ~f ~e outer met~1 :~ pip~ 92 ~d embcddod wi~e~ g4. l~ere~ore, ~he embod1men~ ~own in IFIG. 8 is pr~ble ~o~ app1ig~t~oa~ r~gu1~ h1gher &u~e~t ~t~nsity : ~ ~uch ~ e1~ctrom~s~ u~ed ir1 a ~t~ magll~c fle1d.
FIGt~ 10 î11ustrat~ a h~3110w compo~ite ~cGor~ing ~o ~e pr~ t inven~o~. In this ~mbodim~ ~ ollte~ m~1 pipe 112 ~g~r ~ m~dc of preciou~ ~st~l~ ~d ~;~y o~her m~ uch a~ ~pp~rc ~[~weYer, 1n ~e A~ Ca~B tha~ the outer pip~ il2 i~ ~nt ma~e of p~ociou~ metal, ~n inner .~
;-'', ~u~a~B of tho pipe 112 mu~t hav~ ~ ~nner li~ y~r or ~nt~edia~e .... .

'~, layer of precious m~tal 113. This inn~r l~i~ng layer ~n be produced by conven~lon~l technique such as vacuum-depositiorl, ~putterin~, elect~npl~ting etc.
A hollow composite ~uch as ~hown in IFI~. 10 Gan b~ produced by ~e follo~g st~s:
At first, powd~r~ of Y2(~3. ~CO3 and CuO w~re mixed wi~h such an atom ratio of Y: Ba: Cll becomes to l: 2: 3 ~nd ~hetl the resul~ng mixture W~9 compa~d ~nd p~el~narily ~in~recl &t ~20 ~C.
TJnen, the sin~e~d m~s is pul~er~ed and ~mpacte~ ~ga~n. ~is compaclt is fu~er s~ntered ~ 1,080 C ltO ~roduce a s~tered btock which i~ u~ed a~
a ta~g~ for spu~erin~.
~ ollo~ing i~ ~put~r~ng COlld~ 118 to ~rodllce a ~ m layor of 6upercon~ctmg c,o~npo~d oxid~ on ~ er ~urfaec of ~ platinum layer depo~it$d on ~n inner gurf~ce of ~ ~opper pipe havi~g ul ~ncr diamet~r of S0 mm, a w~ kns~ of 2 mm aad a l~gth ~100 mm:
yg~ ~1 pro~su~e: 4 x 1~ To~r ~gon p~ti~l pro~sure: 3 x 10 a ~rr ~, Sub~trat~ tomperat~: 7~ ~C
~ubs~t~ bi~ v~ ge: ~ ~ V
lE~ e~cy powder: 2S W/cm2 3~50po&i~ion ra~: 0.5 A/~ec Total ~ bout 1 ~m FI(il. ll ls a ill~str~l~e ~d diag~m~tlc~l drawtRg of ~n ~p~atus whicll c~ ppli~ to pr~ductlo~ of ~ w~po~it~ accord~n~
3 ~e preso~ invonti~}n ~ tinuou~ly.
ca~ m~t4ri~1 G~r~mic pourd~r ls pr~fe~ably bl~nded with or~a~ic b~nd~r ~d can ~ p~;pared ~ llow~ng:
~, ' , "

.. '.~ .
,~

:'' . . ' ', . ' . ' ::' , ': . . . .. . . .

',:'' ' . ;,, ' '' ' : ' ~ :

~ 3 ~
At ~irst, powders of ~C)3, Ba~CO3 and CuO each h~v~n~ puri~ of more ~han 3 N ~d an ~rer~ge pa~icle si~e of ~ ,~m w~re mL~{ed with ~ueh an altom ratio ~h~ the pr~ort~ of Ba, ~ ~d Cu in a composition of (Ba1 ~cY~)CuSOz co~spoIlcl ~ values of X 0.2 and y = 1 ~d then the resultin~ mlxture was sllltered la air ~t 920 ~C for 12 hou~s. rh~n, the sintered mass is pulverized in mor~ar. A~t~r the same procedur~ ~f slntering and pulve~æ~ion 1~ repea~ed for ~hre~ tim~, the ~gsulting gintered powder is gxoLuld ~y hi~ puri~ a balls ~n a ball mlll ~or 5 hours ~o ob~a~ a m~tsrial powd~r haviIlg ~ ~v~e pa~le ~iz~ of 1 th~n S ~m.
~ he material powder i~ ~g~d ~d kn e~ded wi~h a b~der of P~B
(poly~i~ylbu~yl~l~ in a ~o~vsnt ~ ~olu~e ~t~ning a p~a~tic~z~ ~f r3~3P
(dibutylph~ar~e). The re8ul~n~ paste iB ~hap~ ~o ~ ~hee~ hav~g a ~schless of 0.8 m~s; a wid~ of 300 mm and ~ of S m ~d ~ried to re~dy to bo u~ed ~ an ~ hown ~ ~It ;r 11 The ~pparatlJs ~how~ ~n PI~it. 11 ~clud~s ~ ~on~inuou~ ~urnace besin~ provided wlth ~uro hea~g ~ne~ of a bindorDremoYl~g zone 242 ~d a ~inter~g zo~e 243. ~ ol~atsd ~h,~ed ~pe o~ wire 244 is ~upplied to a~ t of ~e birld~r-~m~g z~e 242 ~rom a coil~ 245.
Th~ ~lon~at~dl a~lcl~ 244 unwound ~rom ~e coll~r 245 i~ ~ed conti~llou~ly to ~ho binderDremo~ z~ 242 ill w~ ~e elong~ted axti~l~ 244 iis h~ted ~t a ~ r~i of 400 ~a 700 C to remo~e the bi:~der out of ~o~ n~ted ~clo ~44.
., After th~ b~d~r~emoYi~g zoxle 2~, the olorlg~ed ar~i~to 244 is p~BSed to a g~t~uous lin~ng ~io~ 24~ w~lcb i~ position~d a~ ~he down~t~e~ of ~ bind~r-romovi~g zo~ 242. Th~ cont~nuous lini~g ~tation ~4~ i~ p~videt w~th a drum 248 for ~dlng a ~hoet 247 of pr~ious m~l or alloy to ~ ~uide 24~ wher~ the i~he~it ~47 iis wound .~ , ,~: .. ,: ., ,. .. . : . : . .. :

~32~
around ~he elorlgated ~r~icle 247. ~ xea~n of the wound ~heet 2~7 is welded by me~n~ of a la~e~ weldgr 220 so ~at ~he elonl3ated a~ le 24 wrapped by the me~al sheet ~47.
The re~ul~ mposi~e omp~s~ng ~he elo~ga~ed ~ le 244 ~d the cover~n~ sheet or outer s~ 247 ls ~en p~ssed to ~ i~in~ e 243 whe~e the c~mpo~i~e is hea~d ~ ~ temp~ e 9f 850 to 950 C in o~y~en con~a~ atmo~ph~r~ to sinter th~ elonga~gd ar~lcl~. The longitudin~l d~mP,sl~ion or leng~h of the s~te~ zon~ 243 ~d ~h~
~dYancin$ veloGi~ of ~he ~mposite ~ ju~ed in s1aCh mamler ~h~t ~he sinterin~ i~ per~o~med compl~tely.
~ he pro~u~ ~41 thus obltai~ed 1~ cool~d dowrl ~lowly a~ ~ cooling ~eed of ~ C/mitl ~nd m~y be wou~d a~u~ a drum 242 ~ st~k. rhe prodll~t pC7~ S~:~I enou~h ~exibl~ nd ~elg;~u~po~g prop~r;io~, s~ncc t:he elon~ated ~:icle 244 ¢o~ e b~do:r. ~ pp~a~s s~own ~n ~ o~ ~e ~er~ r~ti~ ti:nuo~ y ~t h~sher pro~ctlvi~y.
The pr~ produ~ed by th~ ~ov~me~gioned app~rat~ her hsat~e~ed for ~x~ple ~t 7~ C ~or 36 h~ der oa~y~en contain1n33 a~m~spl~er~ ~o obt~ a supgr~o~duct~ p3~i~g sh~ , 3B.
compos~te ~h~wxl ~n ~1~3. 9 c:a~ bo ~i~o p~odu~d by ~hc .~ app~ratu~ thi~ ~a~e1 wh~ the p~ste i~ ~h~p~d i~to a she~t h~v~ ic~s~ o~ 0.8 mm, a w~d~ of 300 mm ~d a ~eng~h of S
m~ for ex~pl~ flPly pl~ YVi~W w~ co 1~ ~idt~d pre~riou~ly ~r emb~dded ~ heet ~nd dri~d to ready to b~ us~d ~n an ~pparatlls ~hown in ~IG. 1 l . In ~ ~pp~ bt~der ~ ro~QYed $~ ~00 to 700 C ~d ~ æilver ~e~ i~ p~ ~und ~o ~he~ ~ ul~g c~npo~lte is he~d in air a~ 93~ C ~or S 3ho~ to si~er ~he ~he~
'1 .
~I .

17r J` ~ ` : ~

~ ~\

l~e ~omposite c~mprising ~e elon~a~ed compoland oxid~ an~l ~he outer n:letal she~ p~duced by ~h~ presen~ inYen~ion can be ~ap~d or clefo~ned in~o a desir~d ~on~lgurati~n ~ucb ~s a coil o~ ~he like ~e ~o the hig~er ~l~xibili~y and ~elf-~uppo~ g proper~, ~o tha~ the ~ints~ng c~ be perfo~med ifl th~ condi~isn of the colled ~ollfiguration or ~n a condi~ion that ~e coiled 1~ supporeed O~ y o~her conduc~Y~ b~dy. The exi~ence of the shea~ of Pt m~t~l or its ~llo~r ~Is~ increa~e ~he clefle~l~e s~
T~e compo~lte~ obt~ined b3~ th8 abovemen~oned processe~
according to ~he pre~ent Inv~rltioll ~an be u~illzed in ~ ~riety of appli~a~io~s of ~upe~onduc~ors ~s they ~e~ How~ver, when ~ cle~ ce which m~y occu~ eYentually betwe~ the outor met~l p~pe ~d the 3~ntered comp~uz~d oxid~ ~re i~ ~nd~rable, the composit~ ~n be ~ur~r c~ulked or ~ nder modg~ate conditloll dur~g the ~terin~ oper~t~o~
or be~or~ t~e ~omp~ lo~ hea~O ~o ~Ire-drawlng ~ pr~ferably 3 p~ed dur~ng thc ~terin~ ~t~o.
~ still ~l~er va~a~iorl, ~e ~uter md~ p~ m~y 3~a~re ~ plu~
o~ al r~ es or holc~ o~ boa~ in wh~ lC m~te~i~l powdcr i~ f~lle~ :
whi~h i~ sintered ~cco~ g ~ ~e px~ce~ de~cri~ed he~above.
;1 sku~ re, ~ out~m~lpip~unctio~sa~ o~tradi~tpa~s~go during ~:
~, qu~nc~ng ~ge ~nd a by~ of ~lo~ic ~Ten~ wherl ~up~r~onductlvi~r ~s b~ o I~ pp~ o ~cr~ptlon ~bovemen~oned ~t thex~ i~ no pos~ibili~r of che~xlical reductlo~ of ~ a~a~ com~und oxido ~i~h the o~ter met~i p~ ~Rd honce ~o ~upo~nducto~ ts ~abilized chemically, becau~e ~he pipo i~ ~d~ ~ preciou~ me~al or l~ te~ IRy~r made ;l of p~eci~u~ me~il. Namely~ ~ resuI~ng ~r~lc wl~e ~ibl~s ~pro~ed prop~rty o~ ~upercoIlduct~vib~ ~ to lt~ c~u~t~l stmcture a~d ~xyg ~flciency which ~e c~itical f~ or In perov~klte ~ or qu~i-p~rovsk~te t~ ~
J : -~.~
~ 3 2 ~.L ~
typ~ supercorldLIctors is ~sured. S~ill moreS ~in~ ~e co~po~ of ~he preserlt in~elltiprl is 1sol~ted ~m 02~d~ti~re a~osphere bec~u~ o~ ~he presence of the o~ me~al shea~, ~e pero~ski~ç ~e or qua~i pe~ovski~
type superconductars which has n~t hl~r ~i~t~c~ ~o oxl~ion c~ b~
p~otected f~om 5U~Olmd a~osph~r~ ef~ecti~ely.
mpo~ltes ~b~alned ~ ~e presen~ ntion c~ be util~zed sup~o~ductin~ or p~ dus ~o ~he~r hi~h ~nd stable ~.

On~ of prefelTed embodir~aeng of ~he compound ~xide from which the ~uper~ncl~c~or i~ compo~ed i~ ~ compou~d o~Ei~ repres~ed by the ge~er~l fo~ula:
x,Bx )y~z 11l whlch a s~ands ~r ~ el~mellt s~l~c~d iErorn T~ ~oup of ~h~
Periodic Table, ~ s~ or ~ elomo~t ~ele~ rom ~I~ group of '~ tbe P~odic Table ~d y ~ r a~l elemen~ selected ~rom a group co~nprl~ln~ Ib~ IIb~ II[lb ~d VIII ~roup of thg PBXiOdiC
Table~ a~d a ~mall l~rof 6~ ~pres~ ~ aton~ic ~atlo of ,B`and u~nb~ whlch ~a~is~e~ a r~ e oiE 0.1 ~ x ~ 0~9 w~h re~p~t :~ to the t~l ~ (a~3 whi~ ~ ual to 1, 8fflal] letter~ ~f i'y" ~d "z" repr~en~ c r~lo~ oP y and oxyg~n ~ resp~ctiY~ly a2ld tis~y r~e~ oP 1.0 ~ y ~ 4.0 ~d 1 ~ ~ ~ 5 ~p~tlvely.
he ~up~rcond~ ~mpound oxld~ have pr~rably p~ovskit~
3~ ~ype ~cl;ur~ or ~a~i-peroY~lte ~e BtrUC~U~. The~ to~m of ~quasi~
per~Y~te ~e ~ ' ~e~s ~ny o~ide ~at ~ b~ ~sido~ed to h~ve '~ su~h ~ tal æt~ctur~ that i~ slmil~r to pe~it~-f ype ~x~de~ ~d may 'I .

~, , . ,- . . . .. . - . . , .. ... , .. - . .

.. . .
".

~ 3 ~D
include ~R o~horhomblcally di~o~ed peroYski~e or a dls~or~esl o~ en~
deficiellt pe~vslklte or th~ l~ke.
In p~actice, ~e el~men$ ~ is p~e~erably selected ~r~m E~ ~d/or Ca and th~ elem~nt ~ i~ pre~er~bly selected fi~om Y, La ~d/or ~ Anid sllch as Sc, Ce, ~d, Hg, ~r~ 'rm, Yb, Lu and :he elem~t y ls prefer&bly Cu. It can be mantioned, a~ prefs~red sompouIld oxide~ obtaine~ by comblrlations of the~e elemelltg, B~-Y-Cu-O ~e sx~de such a~
YBa~Cu35~7~, I3a-La~Cu O ty~ ~idg or Sr La~ O ~p~ ~id~ ~uGh ~s L~ 9 B~XI2CIIO4~Y~ in ~rhich ~ and y ~Te numb~ which ~
In c~e OI Ba-Y-~u typ~ comp~und 4gide~, a pl~por~io~ of ~om 10 to 80 % of Ba may be ~3ubst~ sd by ~ne or t:wo el~ment~ ~lected ~n a gro~
~omp~sing M~, C~ and Sr and/or a p~ of fro~ 10 ~o 80 % of Y
may be ~ubstileu~od by O~G or two ~lemen~ sele~ed from ~ group ~omp~ L~ a~d l~a~id~ If th~ p~pori~o~s of ~Se substltll~nts becom~ out~id~ ~f the ~bovemo~tI~ned ~ge of ~r~m 10 to 80 Y~, no ~xnp~vem~nt ~f~up~n~cgi~ acpect~
I~ t~e pre~e~ omb~d~me~t9 th~ ~ompou~d o~do typs supercon~ctor ~ be prop~ r~ wde~ whi~h n~y be ~i) ~ powder ~tur~ s pow~ or car~age powdor~ of ~nsti~ent el~mont~ of a compou~d ~a~ide to b~ p~ducod, ~ud~ a~ BaC:~3, Y~O~, Cu13or~ii)a in~edp~deroge~m~undo~d~proparedby~ te~g the p~wde~ ztur~ of (l~ ~d ~021 by pulv~i~g ob~od ~in~e~d ma~
such ~s YB~2~u307 d ~ la al~x, 13a~12~04~y.
lhe sfntered powdo~ ml~ (ii) is p~erabl~ ~o f~cili~ate ~tr~l of pr~portions of ~con~ aeltt~ n~ oma~lalpowderin order to ~btai~ a u~i~o~m p~oduct of ~in~;od contlpound o~idc h~ a pr~per propor~on~ of ~e con~titu~t elem~nt~.
....

,,~,i . . ~ ,. , . . - ..... ,. .. . - ...

, ~ , ` ' , :'., " ~ . : ` ' . ` ' ' . . ' `: `

`'~ ' ' : ' ' ' ` . : " . `

Tbe ma~erlal powd~ may be pr~p~ed also ~om fluorid~, nl~a~e, xul~te, or the like in ~tlon ts or ~ pl~ce of ~ oxi~le a~d c~lbo~ate.
Acco~dan~ ~o a ~e~d ~mb~d~n~nt, ~ition~l ~era~lon~ such a~
wire-~awin~, heat-tr~a~en~ or ~ne~lmg c~ be c~ ed out b~E~re ~r a~ter o~ dur~~ he si~terin~ ~ra~io~. ~amely~ aP~er a powder mixt~re of co~pou~ds i~ comp~cted ~ ~ m~l pi~ n~le of p~ciou~ met~t~ ~u~
as gold~ ~ilver or plat~um me~al~, ~e pip~ is ~ubjec~ed ~o ~ se~g of o;perations compr~ ~e~ling, ~i~-~w~n~ a~ n~g~
~ wire~drf~ y b~ med by ~y me~$ including d~
roller diss~ ~llin~ ~ill, ~w~ uni~ o~ oxtluder. ~he sint~g can be c~ried out at ~ ~mp~ratur~ r~ betYveen ~ upper limit whlch i~
deflgled by a melting poin~ whi~h co~gsp~nd~ ~o ~ low~ melt~n~ poln~
of ~ny on~ of co~s~tu~g c~mpo~e~t~ e m~ l powder ~nd ~ lawer limi~ wh~ low~ by 100 ~C ~n s~id u~e~ Thc ~alin~ can be ~ied out at a t~per~tu~ which ~ low~ th~ ~ n~
~mp~ uxe, p~rably l~wor ~a~ 160 ~C. Cooling of h~ted compo~ite a~r ~ ~eali~g ~d ~i~te~n3~ opera~an$ 1~ c~ d ~ut at a cooling s~ed ~f lower ~n 50 0~ ~in9 more pa~ ly lower th~n lO ~CJmi~.
I~ ~s al~o ~s~lble to ~mo~,re ~h~ ou~r mo~l plp~ ~er ~ anno~ or wlr~ wingO
A~ordin~ ~o ~her pr~rr~d embod~t, a~t~r a pow~r m~u3r~ of co~pou~s i~ c~pac~d ill a ~e~al pap~ m~de of ~ilv~, the p~pe i~ ~u~ ed to a 3eric~ of operati~ compri~ wl~e-d~w~"ntg~edl~te ~ering, wi~ ~d sin~ing.
~ cordln$ ~o ~ o~h~r pr~d embodimo~t, ~ a~ditto ~ ou~ mc~al layor i~ ~ned ~ an o~er ~ ac~ oiF the pipe, N~nely~
a~t~r a po~0r ~i~e ~ comp~L~d~ o~np~cted ~ a met~l pip~ ~d 3' the pipe ~ ~ubj~ed to an~ealin~ ~d w~ drawin~q ar~ ~dditional ~ut~a `, , - . ,.,, , ~ . . .

~2~
metal layer is a~lied OIl ~he outer ~ur~se of ~e pipe and ~h~n ~he resulting pip~ 15 wl~e-d~awn be~ore the c~mposite is he~ted to ~inter the m~terial powde~.
In this case, t~e additio~l ou~r metal layer c~n be fo~me~ by plating tech;niqu~ or ~Illkin~ or cl~ g ~schrlique ~ which a metal plpe having a larger ~er diameter ~h~ ~e comp~$it~ pip~ is put on the composi~e ~pipe and then i~ caul~d tigh~ly o~ out~r su~ace of the c~mposite pipe. In ~ Iso~ Af~er ~ pîp~ flll~d ~llh ~he m~rl~l powder ther~ w~re d~awn, it is po~tble ~ remove the outer metal pipe at ~he sam~ t~e wh~ ~ ma~l powd~r ~ ~mt~red. The si~tered composite ls c~led at a lower c~ peed.
Th~ dimen~iotlal re~uctlo~ r~o of ~he wire~ w~g i~ pre~e~bly -' wi~ e of ,t6 to 92 56, ~ording ~o ~t~ll ano~er ~mbod~en~ er a powder m~ture of `1 c~ourld~ i~ compa~ed ~n a m~l pipe ~nd the pip~ ls wlre~draw3~, ~he pipo i~ subje~ted ~o a ~ries of op~ra~îon~ eom~ri~in~ aMoailn~, w~e~
dxawin~ and ~ntorir~. Tho $t~ps firorn tho w~re~ win~, ~ne~l~n~ ~d ~ec~d wir~ m~ b~ repe~t~l for B~Ye~ tin~o ~o~r typ~ ~upe~on~uc~r~ whi~h a~B a~li~blo to ~o pr~en~
~n~e~tlonl3lcludefollowin~com~und OX~dl~8:
~13 a Gompouxld oxi~ u~cllldi~ e le~s~ two el~me~$~ nd a2 Iccted f~om ~a gfOUp of ~e ~e~iod~c T~bl~, ~ eleme~ 8 seIect~d from :~1! V~ group of ~ae P$~otli~;: T~ble ~d an ole~nen~ y ~lo~ted ~r~m ~ group ;~ ~omp~s~n$ Ib, IIb" Il~b ~d ~ ~u~ OI ~ho P~riot~ T~ble.
''.7~1 Pal1icula~y~ the elemetl~ al and ~2~ pre~e~bly Sr a~d S~ theelemen~
i~ prs~?~bly E~i ~d ~o ~lem sn~ y ~ ~re~ably Cu BU~l a3 a ~9 t~ Ca-~r~Bi~Cu ~ ~xide~ ?fo~ ex~m~le ~2Sr4B~ u60~

?i ':, ' ?" aan ~.~2 (ii) a compound oxide mclu~ a~ lea~ two ~lements al a~d a~
selected from IIa ~oup of the Periodic ~ble, ~n el~nen~ ~ sele~ted firom II~a ~oup ot the P~iodi~ Table ~nd ~ ~lement y sel~cg~d ~om a ~r4up compr~sill~ Ib, IIb, IIIb ~nd ~III g~p of the Perioclic Table.
Pa~ticularly, the el~ment o~l and ~2 i~ pr~ferably 33a and Ca, the el~me~t ~
i~ p~e~ably Tl and t~ elemen~ y is pre~erably Cu suçh a~ ~ c~s~ of Tk~Ba~C~Cu6020~
Novv, the p~ce~s ~ordin~ to the presetl~ ~vention w~ll be described with refer~nce to illu~t~tive Bxamples, but the ~cope of ~he pre~e~t l~ven~loll ~hould ~o~ be limi~ed ~&~reto.

~91 A powder ~nixture of l~a(N03)2, Y~NI:~3)3 ~d ~0 oa~h h~vin~
pur~ty of 9~.9 Q~o wa~ ~c~ded ~ to~ ra~o of Y ~ Cu 8 1 3 ~n et~nol ~nd the~ ~in~er~d p~viou~ly ~ 7~0 ~C for 3 hour3. 'rhe ~interod ma~s ob~a~ed wa~ thon pulY~ ed ~ a b~ll mill ~o prepa~e ~ ~t~red powderh~v~ a part~cle ~æo of le~s ~ 10 ,u.~.
~ he ~tered powder w~s com~d In 3l p~6 mad~ of sil~er h~v~
an outer dlamet~r of 10 mm ~d ~ ~11 thic~os~ oî I mm ~nd then ~in~red at 910 (: for 7 hou~g. A~ ~e end of th~ ~ate~ t~ge and d~ pip~ ls ~ a h~ted co2ldil:ion, tho pipe w~ sub~sted to wire~
drawlng ~ r~duce ~9 outer dt~neter to 8 ~ a~d ~n ~lod a~ a G~it g ~peed c~f 15 4~ /min~
Th~,, the plpe wa~ ~e~he~od ~t 300 ~ ~r 20 mig~uto~ ~ tbo~
CQ~g~ at ~ c~ling ~pec3i of 10 CJ~
~ ord~g ~o ~ u$ual me~od7 tvv~ pa~6 of de~es w~ ~olde~ed Otl a ~amplo (30 cm lo~g~ fr~ th~ re3ult~ng ~m~ite wi~ ~ilver pa~te ~d thel the ~mple w~ Immers~d ~ l~qu~dlz~d ni~r~ge~ a c~yos~a~ to cool the composi~e down ~o ;~ tem~erabu~ w~ere no re~lstanee was obser~ed. ~e~ temper~ture depetld~n~e vf r~ist~nce of ~he s~mple w~s dete~ined with ris~g ~e tem~erat~re ~clually. The result~
~evealed that ~he s~nple of wir~ showedl ~ ~emp~rature of 117 K wher~ ~n o~dinaIy rssist~ce wa~ obser~r$~
l~e temper~h~ dependence of re~s~anc~ w~s determ~n~d by ~our probe method in cryos~t ~d ~mp~r~ure w~s ~easur~d by ~ ~lib~a~ed ~u(F~-Ag ~e~ocouple.
~ e superc~n~ct~ng proper~y of ~i~ s2mple was p~s~red up lo curv~ture of IOO Ir~ ~d~ a c~ned con~iguza~iot3..

~ ~arn~ pro~edu~ x~nple 1 was ~gpea~ed except ~ th~ :
s~tered powd~r w~ comp~cted in ~ p~p8 m~de of pl~
The re~ul~ ~ve~lod ~h~t ~¢ ~mple obt~tned iYihowed the ~e tsmperi~ture of 117 K wl~ere ~ ordl~ry r~iistAnci~ ~vi~ o~ rved a~
Exiample 1, E~
20.~ % by wei~ ~f co2n~nc~ially a~il~ble Y20~ powder~ ~4 7 %
~y ~ of commercially ævait~bl~ B~C03 ~d 24,$ % by ~elg~t o~
- ~ommer~i~lly ~Yailable GuO w~ ~ atto~ter in wet and ~he ~i~d. ~ho dri~d powd~r w~ pa~ mold~d at a p~e~r~ of 100 kg/~a ~d then s~ntered at 880 QC~ air for 24 holl~ i~d ~hen was pulverizecl p~ ed ~ougll a 010~ to ob~ powdcr of 100 mesh ~d~. The '1 abore~n~lon~d operatio~s firom ~ sLn~e~ing to scre~ing we~ repei~ted I fo~ threo time~.

1 .
.,, . ~

~1 .
., ''J.'~ ''" . ' ' .' ' ' .' . ' " " .'. ' ' " `', . ',: . ; , ', ' , ,`,~' ~-'.' ' . , ' ` ' "` ~ ' ' . ., ' ' ' ' ,,, 3 ~
~ ter treatrflent of gr~nulatlon, ~e ~anula~ed materi~l powder ~s compac~ed ints a plla~ rn p~pe h~ving ~ outer di~m~er oP ~ mm, ~n ~nn~ di~neter of 4 mm and ~ length of 1 m a~d ~posit~ ~ds of ~ pipe were clo~ed.
The res~ltixlg platiIlum pip~8 ~lled wi~ the mate~al powder w~s subJected to wlre-draw~ng to ~uc~ ~s outer ~iamoter down to 4 mm and ~en w~s bea~ed in air ~ ~nter thc mateEi~l powd~ ~t 930 C for 3 hour~
during whl~h the out~r platinum pipe was p~sled o~ by ~ die ~h~ough which ~he pipe was pas~ed. A~er then9 ~e product w~s Gooled at a co~ peed of 8 ~Jmin to ob~ a ~red c~ramic wir~ having a ~in film layer of pla~um of O.û5 mm ~Ick.
)b~rv~ioxl of a cm~ sec~ n of ~e ~ir tered ce~nic ~r~ r~ve~let su~h ~ ~ th~lt a tl~ ur~o lay~ of 0.4 mm ~}~ck of th~ ~e~ic ~ire tum r~d bcc~u~e C~ ) w~ red~ed ~o Cu wbile ~o cont~l po~ion of ~he ~te~ed ~er~nlc wire u~a~ le~t ~ a d~rk ~oen ~olor of p~rov~kite.
~oasu~ernent of th~ ~itieal ~en:lpe~a~e ~TIc~ of ~hls sup~x~onduct~
wire of perov~ldte ~howed a v~l~ of 45 iK.
Th~ sam~ pro~edure wa~ ~epe~ed ~ ~bov~ except thai a fl~er pl~uan pipe h~Ym~ u~g~ di~n~ter of 3 m~ ~d an l~ner d~mete~ of

2 mm was u~ed ~d w~e~ wlth hl~e~ dimen~ l reducti~n ratio of up t~ ~ if inal ollt~ diam~ of ~.4 mmO In ~ ca~, no r~tuction of ~uO wa$ ob~e~ved bu~ 03ult~ red cor~m1c wir~ c~n~lsted tot~lly of ~ p¢r4~8kit~ $ the ~cal t~p~ of ~7 K.

.~ .

~ 5 20~8 % b~y wei~ht of c~mmer~lly aYailabl~ Y~03 ~wder, 54.7 ~
~i by w~ight ~f eomme~cially ~Y~Uable BaC03 and ~4.5 % by ~eight of con~n~rs~lly ~v~lla~le ~O wore m~ed ~ a attor~er in wet ~d the ., d~le~d. The ~i~d p~wd~ ~Va5 p~3~molded a~ a pre~s~F~ of 100 kglc~n2 and t~en ~lntered at 8$0 C ill air ~or ~4 hours ~ the~ wa~ pul~ized and passed ~ro~8~ a sie~ to ob~atn powder of 100 me~h~und~r. ~he abovemensiorled operatiorls ~om ~he sin~ t~ 5C~ell~ W~ re~a~ed for th~ee tlmes.
The ob~ained s~n~ered mater~l powder w~s comp~ted into a pl~inum pip~ hav~g an ou~ dl~ter o~ S mm, ~ i~ner ~ of 4 mm ~nd a l~ng~ of 1 m and o~posi~ of ~ pi~ w~ clos~ e result~g plat~num pipe fllled ~ the ma~al pow~r wa~ he~ted ~o 600 C a~d ~ e21ed.
20 sample~ of ~ led platinum pips~s were pa~sed ~rough ~
serie~ of rolier dios t~ obt~ the ~1 ou~e~ diameter of 1~0 mm unde~
su~h c~nditio~ t th~ n~ l ~d~ctlon ~ti~ ~ cro~ s~ction~l dir~&tiorl p~r one r~u~tl4~ bl~l~ was 38 Yo. In thi~ C~90, br~kage of pip~ w~g~ ob~vetl a~ su~ fr~querlci~ are sh~ ble 1.
T~bl~ 1 I:~lam~ter w~ bre~cQ$o o~urrad ~re~en~r of breakago i, ~ b~e~a~e 06cLuTed up to 1.0 ~
Brea~go oc~ betw~ 1.0 mm ~d 1.1 mm 8 Br~age ~CCUIT~ l~ 1 ~ ~d 1.5 ~ 7 Brea~ ~ d betw~ n D~d 2-01~ 3 l~ e ~curred bo~eerl 2.0 ~ and 2D4 mm 1,1, e s~le proce~ a~ ~vo wa~ ro~eat~ G~&~pt ~a~ the Pt pip~
flll~d with ~g sin~r~d po~r w~ eadrf~ ~u~ ;tatio~ die.
~ thi~ ca~e~ ~ ~re~ue~cy ~ br~a$~ i ncr~ed flv~ ~im~ more ~ e a~ovem~ ned wire-~w~n~ by roller d~es.
'J~ , ~D . .
' '~
.1 , , ''.

'~ J~"r~ ~
E~oth of ~ve s~ple~ p~epared by roller dies ~d one sample ~hich could be drowrl up ~o a di~meter of 1.0 mm wi~hout a~y breakag~ by ~he conventlon~l statioll~y die Yere ~te~d ~t 7S0 (: for 20 m~n~es. 'rhen~
reduction in cro~s ~cti~ of ~e pipes w~ rep~ted by th~ roll~r die~
by the stat~orl~y dies for re~e~ti~ ssmples to o~tair~ an outer diame~e~
of 0.3 mm. T~e r~ult revealed ~h~t the fl~re sam,~les p~sed t~rough roller di~s &ould be d~wn up ~o ~e flnal diameter of 0.3 znm, while the one ~mpJ~ passed ~rou~ s~at~n~ry di~ br~c at a di~eter of 0.4~
~.
The~, ~11 of the ~mpl~ were subjec~d ~o the ~1 ~inter ng at 850 ~C ~r 5 ho~ en the s~nt~r~ c~mpl~ composi~e w~ ~ooled at a cooli~ ra~e of 10 ~C:/~in. l~e~, ~e criti~l ~perature ~T~ was measured on ~ho s~nple which was pA~ed throu;~h ~~ die~ t~ a di~met~ of 0.3 mm ~d ~int~ed at 930 C f~ 3 ho~r~ .
Mea~uretnen~ of t~e crll;i~al ~mperah~a wa~ ~a2~ed out by c~nventional fou~ prol~ d Ln which, af~r ~le~od~ w~re connected ~ ~e re~u~t~n~ wirG w~ c~du~ti~ ~tlv~ p~to, the wl~ w~ Imm~ed in ll~tdi~ed hydx~n to caol ~e w~e d4~n to a ~np~rature of 25 R
cryo~at~ T~mper~ me~ red by ~ calibr~ted Au(~e~-Ag l;he~uplo. Th&~ ~g ~n~pgr~ture depoald~llco of r~si~t~co of ~he ~npl~ w~ d~tormined u~ e ~ompe~ e gr~ ally. ~ results re~lod th~t ~he sampl~ OI t~e p~o~nt ~n~ tlo~ exhibited ~u~r~duc~ivl&y up to ~ iv81~ lO~ ~pe~e ~ 99 K.
P~ comp~ ~, tho ~ l t~mpo~tu~ of ~he ~mple pr$~arèd by ~e 8~tion~ di~ wa~ alsc~ me~ured ~ho ~:~ult ~ev~lod ~t ~e ~tic~
npora~e of gh~ np~tivo ex~n~ple i~ ~0 K l~w~r than th~ ~t~l tempe~atur~ ~P th¢ ~mpl~i prep~d b~ oller ~les. 'rhls d~crep~ncy might b~ ~a~ed by f~n~ cra~k~ pr~uced in~ido the cor~ni~ wire. ~

.~ .

~ct w~s also ~uppor~e~ by mea~llrem@~ of cu~eZ~ densa~y in vvh~ch the sample obta~ned b~ the ~oll~r dies show~d h~ 3her critiçal de3lsl~y ~a~ he s~ple preparsd ~g ~ st~t~on~y d~e~.

~ same s~tered mat~rial powder ~s l~am~ 4 WQ~ used ~nd wa~
comp~cted into a platlnum pipe ~avh~g ~ ~uter di~eter o~ 5 mm, ~n lnner ~iamster of 4 mm arld a leng~ of 1 m and o~lte end~ of ~ plpe were closed. ~e resul~ plat~um plpe fllled w~ terial powd~r was hea~ed ~o 880 ~C ~r 2 hou~ and then ~Mealed. Th~ ~nnealod pl~t~um pipes w;~s pa~d ~oa~ seri~ of rollgr die~ to re~e to ~n :
olater di~m~ter of 4.1 mm, Then, ~g~es ~ pipe w~ fur~r he~ted at ~00 9C: for 1 bou~ d ~e~ ~ne&l~d~ its ~ t~ w~ ~u~aer ~duced to 3.2 ~un, A p~ece of the ~e~ult~ p~pe wa~ $1ined ~ially ~d @~ami~ed ~l~ cop}cally ~o ~d innumerablc cra~ks of los~ 0.8 n~ wid~ 6~1tered ce~nic m~s whi~h mi~ be c~uscd by ~old wo~r~ o~ ~ sint~red ce~lc.
Ihe ~ic WirB of 3.2 mm ~n li~eter wa~ ~ef~ er heag~cl at 930 ~C ~ ~ hour~ ~d cool~ 0wly ~t a coolt~g ~pe~d of 10 ~lm~n.
~o re~ul~$ p~ vY~ ~ a~i~ axi~lly a~d e~amin~d ml~ra~copic~
~o ~nd ~ c~ l t~pB~atU~ 0~ G~ C w~i W~
K. ~10 C~Gal t~a~8 8~tld rB~ anC~ wcre ~ ed by ~e ~ne me~hod ~ ~ nple 4.
.
~h I
ne p~o~du:re ~ Ex~plo 4 wa$ ~peated ~o obt~ ampl~s oP co~posîtos ea~ h~ n o~ter d~c~et of 0.3 n~n ~d eQm~ g an outer pl~in~ p~0 and ~ sinto~d ~a~s ~ und~d ti~tly by ~he ~:
.:

i ~ ,., , , . , , , : ~ . . ! , , . I . .,, , " , " . . .
".'; ' . ' '; '. . '` '' ' "'- ' . "' ' ' ' `.' , ', 1 '., . ,' , ., '.~ , , , J ~L ,L ~ ~
pla~inum pipe. The sample~ were ho~ever lacking ln u~ , namely ~he Y~tion In diame~eI of ~hes~ sam~ was ~ 0,16 m~. Still mo~, ~h~
oLIter platinum p1pe hsd llot enou~h s~e~ to b~ge.
The~e~re, another plat~nllm p~pe haY~ng ~ outer diamet~r of 3 mm and an ~ r diameger of 1,5 mm wa~ put on on~ of the s~3~ples llaving an outer diameter of l.O mm ob~ined in l~xampl~ 4 ~d wa~
c~ulked to obtain ~ cladded compo i~e. Thls cladded comp3~it~ was ~her wire-~wn t~ a di~ne~er ~1.5 mm ~1 tben sin~e~ed ~t 930 ~C
fo~ 3 hour~ ~nd ~oled sl~wly ~t a cooll~g speet of 10 ~C/min. T~19 re~ultln~ product gh~wed a uni~ox~ a~oa~nc~ hs~d ~h~ re~d ~arlation In di~e~er of i O.OOg mm. Thl~ product m~intain~d a relatively highe~ sup~rc~ndu~Yi~y up ~ 97 ~. ~e c~tic~ tempera~u~e ~d resas~ance w~r~ detgrm~ned by th~ me~ as ~mple 4.
~, 8~.5 ~ by wei~}at oJF cv~me~ially ~vail~ble L~03p~wdg~3 3.1 by wei~h~ of com~e~î~lly ~v~ilabl~ S~C)~ ~ad l 1.4 % by wei~t of ~mmerci~ r a~silable t:!~O wo~ m~ed in a~ ~tto~r ln w~t ~d then ~ied. I~1B dri~d powd~ wa~ p~s~anold~ a~ ~ ~res~u~ of 100 k~
~d ~en s ~nt~r0d ~ ~OO ~C in ~l~ for 20 hou~s ~d ~hen w~ pulve~zgd ~d p~ ~u~sh a ~iev~ to o~ w~er of 100 m~sh~d~.
Aft~ ob~inod ~intered mate~al powder wa~ at~l, it W~B
~mpacted into a pl~n~ pipe ha~n,g ~ ~ater di~e~ oiE 5 n~n, ~
~n~r d~ t~ of 4 n~n ~d ~ 1 m a~d opposite en~ of ~e plpe were ~los~d. Th~ re~ul~ pla~usn pipe fllled w~h tho ~ate~l powder wa6 h~a~ed ~o 1,050 ~C gor 2 h~ur~, r~sultin~ in t~a~ ~Imo~ ~11 of plaLti~um wa~ f~$~ o~ ~e ~t~rod ~er~c ~ore to obta~ ~ wire of ~.7 mm lollg co~ted w~ a Pt lay~ of 0.01 to 0.06 mm thiclc. T~e ~a~iatio~
29~

, .
..

. . .. ~ . . ~ . . ... . .. . - . . . .. , .. I. ... .. .. .... .

, ~ , . . . ~ : . . .

. , - :. . . . . .
... . . .

~ ~3 2 _L ~ ;~
in diameter reduced to ~ 0,006 mm. ~is product ~&mt~lned ~ rel~tiYely hig~er supercondllctivl~ up to 10~ K. Th~ cr1t~cal ~s~npera~ure ~d reslstançe were det~n~ngd by ~e same method ~s ~ ple 4.
i . .:

Powder~ of Ba9 Y~03 and ~0 weire u~ed A ~1~ of ~0.8 % by weight of Y203 powd~r, 54.7 % by wei~ht of Ba p~wder ~d 24.S % by weight of CllO powder were mixed ~ ~ molter ~nd wa~ pres~mold~d.
The r~ulting c~m~ct w~ sin~or~d at 940 C for 15 hour~. The 3~nter~d ~`3 nl~SS W~B ~en pul~e~ized ~ad passed through a ~e~ to ob~in powder of IOO me~h und~r. Tho ~6~cnee of ~ moldl:~g, ~ erill~ ~d pulveri~on ~s sepeated ~or thre6~ ~mes to æb~ a m~t~ri~l powder.
~ nllow~ng ~ur ki~ sf pipe~ werc u~ed:
(i~ Goppcr p~pe harlrl~ ~ outer ~met~ of 20 mm ~d ~n f 15 mm, (il) Sil~ pip~ hav~llg an outer di~olt~r of 2û mm Ind ~ inncr di~noter ~ l5 ~ ~:
Cop~er pipc h~ ou~ dia2m.,~er of 20 nam ~nd a~ inner di~teT ~sf 15 m~ aIId h~ ner l~ ye~ of ~llver, ~d Co~per pipe h~ ster dlam~tor o~ 20 mm ~nd ~ ~nn~r di~me~or of IS rf~ d h~ing a ~er l~ng l~yer ~ ~old, A~t~ the ~ter~d m~t~al powder w~ compac~ in ~e~o plpe~, o~pois~e ~d~ of oa¢h p~p~ w~ e~ o plpes W$~ ~ub~ect~d to swa~ worl~ to redu6~ ~ir ou~sr dlametor to ~ mm. Tho r~sultiA~ i plpo~flllod~ m~ alpovrd~worohe~t~to950C. ::
., Th~ critio~l tompor~ture~ of the ~e~ulti~8 ~ompo~l~e~ were '~ ~tenn~ed ~y ~ B~lS me~ x~mple 4~ result is sb~ n the Table:

. 1 ~ :
,,~ .

~ 3 ~3 fi~ ~np~
(i) ~3 (ii~ 9 ) 9 ' (lV) ~3 i E~amp,lQ2 e ~ame smte~d m~ter~al pawder ~ ~m~l~ 4 was use~ ~d w~s compac~d hl~o ~ va~iety of s~lver-~op~ alloy pipw g~ch h~Yi~ ~ ou~er di~eter of ~ ~x~, ~ in2ler di~e~ ~how~ Pollowill Tabl~ ~d a le~thof 1 im. The~ pipe3 w~ je6ted~wire~ ring work to r~duce ~elr diame~o~ ~o 3.6 mn~.
`~ ~e~e plpes flll~ w~t~ th~ m~teirl~ powdle~ w~re heat~d ~o 930 ~C
fior 3 h~ n ~ ob~aln sintered ~r~ wir~ ~o~e~d wi~ ~ u y coa~
.1 .
ampleæ of the re~ pi~8 werc Cllt ~o be ea~ ed n~ ly ~ ~d~ m~ u~el~ t~ o b~t ~o fl~d for~ of ~ lsyer of A8~0 ~l~ed by ~teimal oxid~ffon the Ag Cu p~p~
7bbls ~u~no~es thg k~d of alloy~ u~ er di~e~r~ af ~e p~, ~d ~h~ cr~ mp0r~ s of ~ ro~ul~
com~e~

^..~
~: . ' ~ i .~ .
-~: ''' ~91- .. :' .. ~ . .

~ ~.

' . . ' ' ~ i , '! . ', ~ ': .. . ... ... . .

~2~-5 ~

~o alloy Vickers Irme~ Critical temper~ture H~ ess D~a. (mffl) (K) . ~ ~
~2.8%~u 4~ 4 ~3 2 A~-2.8%~u 42 4.3

3 ~10%~u 64 4 6~

4 A~-10%C1l 6~ ~.3 70 Ag-20%Cu ~5 4 6~
6 ~a20%Cu 85 4.3 69 7 ~g 3~%~u 1~3 ~ 65 8 ~-30%~u 103 ~.5 78 ,' ~ .
. .
~sm~~
The same powd~ m~xtur~ a~ E~X~lpl8 1 W~ compacted in a 30%Cu atl~y pipe ~nd h~ing ~n out~r diame~ ~ S mm and a w~
~ es~ of 1 m~ ~d ~ sirl~red at 910 C for 7 hour~ e erld ~f t~ 6inte~ sta~ and du~g ~he p~pe 1~ i~ a hsated colldii:ion, ~}e pipe w~s subje~ted to wir~d~w~ ~o reduce lt~ out~ diameter ~o 3.5 mm and hen cool~l ~ a cooli~ag ~p~ed of lS Qt:~/mitl.
~ hen, the p~pe wa~ ~heated ~t 3~0 9C ~ 20 mltlu~ ~d tho cooled at a ~lin~ 8p~ed of 10 C~/mirl.
~ GOr~lg to a u~u~l met~od, two pai~s ~ el~c~odes we~e ~olderçd ~ a ~npl~ ~30 cmL 10ll83 cut ~m ~ ~ul~ing COnlp5~B~ wi~b indlUm p~ste ~d ~e~ the ~e~pgratu~e dope~ e of re~ e ~f ~e s~mple was detormin~d wi~ o t~mpe~ture gradu~lly. ~he re~ s reve~l~d -, that the ~am~l~ of w~ro sh~w~d ~ t~mp~tur~ of 74 K wher~ ~n ordinaly !
resi~t~ce wa~ observ~d.
e ~e~per~e dependence of re~i~ce w~ dete~n~ned by the same m~od as ~x~nple 1 .
.

~ .
i .

.. ., ... , . . .. . ; ;, .. . . . . ~, ., , ,,, . , ~ , ,.~, . ;, .,.. , .,. ~ , . ,i ~ : ' ' '' :

3 ~
~ e supercondLuct~n~ proper~;y of ~ls sample was prese~d llp t~ a cllrva~ure o~ 100 mm und~ a cu~ed conglgu~lon.

~LI
'rhe ~me ma~erial po~d~r a~ ~npl~ 3 w~s comp~c~ed m a A~7 20%C~ ~lloy pipe ha~ ~ ou~er dlamete~ of S mm a~d ~ inne~
diameter of ~ m~ and opposi~e ~nds of th~ p~e w~ closed, ~ e plpe ~lled with ~he m~te~ial powd~r ~ere~ w~ ~u~0cted ~o wire~dxawin~ work ~ redu~ ~s outer d~me~ o 4 ~ ~d then wa~
hea~d a~ g30 C ~r 3 hollr~ to ~nter th0 material powder. The resucl~Lg conlposite ~v~s cool~d slowly ~t a c~ speed of 8 4C~/mill to obtai~ inter~d c~r~mic wire co~ted with ~ Ag-20~uO alI~y ~ayer of 0.0~ icl~.
No 6~emical r~ctio~ of ~he ~inter~d c~r~i~ wire wa~ ob~0~ved on a ~ s ~ectlon ~ereof ~a~ ap~eaffl~e ~ p~rov~lte ~ol~ wa~ ob~0r~t~d~
l terq~ o~nducting wir~ wa~ 75 K.

~Z
The ~ame d~ied powdf~ xampl~ 7 wa~ pro~-molded at a p~e of 100 k~m2 ~d ~en ~i~ter~d a~ 840 ~C ~ ~ir for 3 hour~
thul ur~ pui~e~ize~ and pa~sed ~r~u~ ~ ~ieve ~o o~a~n ~wde~ of 100 mesh-~nder.
Aftgr ~he ob~ined ~int~d m~rial powde~ w~ gra~aula~ed, xhe m~ter~al powder ~YA~ Comp~ d in ~ 10%Cu allciy pipe h~ving ~n ou~ di~m~r of ~ dl~ne~er of 4 ~rA ~d ~ leD~h of 1 m ~nd opposl~g end~ of ~e p~ w~ clo~d.
T~e pipe fllled with th~ m~ l powdo~ thero~ w~ sub~ected ~o wi~raw~n~ wo~k to r~duce it~ ou~er di~ter ~o 3.4 mm ~d ~en w~s ,. . .

.. .: . .; .. . . .. . " . .
., . . . , , .. . , , . . :: :
.. . , . . .. . : , -~ L32~
heated at ~40 3C f~r 12 ~ours in vaccum ~ ~,~ter ~he m~çrial powder.
~e resllltin~g ~rire colted wi~ a .9~g lOY~Cu~ ~lloy l~yer of 0.01 to 0.0 mm thick.
The ~riti~al tem~ratu~ei of thi~ ~up~duc~g wl~e wa~ 79 K.

;~,.

"''~
'.' ~ ' '" ' ;~ I , ~ ' ~ , ...

~ ~ ,' .

Claims (95)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A wire-like composite comprising a compound oxide type superconductor and an outer metal pipe on which said superconductor is supported, characterized in that said outer metal pipe is made of at least one of metals selected from a group comprising gold, silver and platinum metals and their alloys.

2. A composite set forth in Claim 1, characterized in that said outer metal pipe is made of Ag, Au, Pd, Pt, Rh, Ir, Ru, Os or their alloys.

3. A composite set forth in Claim 1, characterized in that said compound oxide type superconductor is in a form of a sintered solid mass compacted in said outer metal pipe.

4. A composite set forth in Claim 1, characterized in that a plurality of metal wires are embedded in said compound oxide type superconductor.

5. A composite set forth in Claim 1, characterized in that said outer metal pipe is perforated so that a part of the compound oxide type superconductor supported by the oute metal pipe is opened to surrounding atmosphere.

6. A composite set forth in Claim 1, characterized in that said outer metal pipe is a cylindrical wire netting.

7. A composite set forth in Claim 1, characterized in that said inner surface of said outer metal pipe has a layer resisting against oxidation which is inactive to the compound oxide.

8. A composite set forth in Claim 7, characterized in that said oxidation resisting layer is composed of an oxide of a material of which said outer metal layer is made.

9. A composite set forth in Claim 1, characterized in that said compound oxide type superconductor is in form of a layer deposited on the inner surface of the outer metal pipe to provide an axial hollow interior passage in the pipe.

10. A composite set forth in Claim 9, characterized in that said outer metal pipe is closed at opposite ends thereof.

11. A composite set forth in Claim 9, characterized in that the axial hollow interior passage in said outer metal pipe is filled with an inert gas.

12. A composite set forth in Claim 9, characterized in that a coolant is circulated through an interior of said axial hollow interior passage.

13. A composite set forth in Claim 1, characterized in that said compound oxide is a compound oxide including an element a .alpha. selected from IIa group of the Periodic Table, an element .beta. selected from IIIa group of the Periodic Table and an element .gamma. selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table.

14. A composite set forth in Claim 13, characterized in that said compound oxide is of qussi-perovskite type oxide.

15. A composite set forth in Claim 13, characterized in that said element .alpha. is Ba, said element .beta. is Y and said element .gamma. is Cu.

16. A composite set forth in Claim 13, characterized in that said element .alpha. is Ba, said element .beta. is La, and said element .gamma. is Cu.

17. A composite set forth in Claim 13, characterized in that said element .alpha. is Sr, said element .beta. is La and said element .gamma. is Cu.

18. A composite set forth in Claim 1, characterized in that said compound oxide is a compound oxide including at least two elements .alpha.1 and .alpha.2 selected from IIa group of the Periodic Table, an element .delta.
selected from Va group of the Periodic Table and an element .gamma. selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table.

19. A composite set forth in Claim 18, characterized in that said element .alpha.1 and .alpha.2 Sr and Ca, said element .delta. is Bi and said element .gamma. is Cu.

20. A composite set forth in Claim 1, characterized in that said compound oxide is a compound oxide including at least two elements .alpha.1 and .alpha.2 selected from IIa group of the Periodic Table, and element .epsilon.
selected from IIIa group of the Periodic Table and an element .gamma. selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table.

21. A composite set forth in Claim 20, characterized in that said element .alpha.1 and .alpha.2 is Ba and Ca, said element .delta. is Tl and element .gamma. is Cu.

22. A process for producing a wire-like composite comprising a compound oxide type superconductor and an outer metal pipe on which said superconductor is supported, characterized by the steps comprising preparing at least one of material powders selected from group comprising (i) a powder mixture of compounds each containing at least one of constituent elements of said compound oxide and (ii) a sintered powder of compound oxide prepared by sintering the powder mixture of (i) and then by pulverizing obtained sintered mass, compacting the material powder in an outer metal pipe made of at least on of metals selected from a group comprising gold, silver and platinum metals and their alloys, and then heating the metal pipe filled with the material powder at a temperature ranging between an upper limit which is defined by a melting point which corresponds to the lowest melting point of any one of constituent components in the material powder and a lower limit which is lower by 100 °C than said upper limit to sinter said material powder inside the outer metal pipe.

23. A process set forth in Claim 22, characterized in that said outer metal pipe is made of Ag, Au, Pd, Pt, Rh, Ir, Ru, Os or their alloys.

24. A process set forth in Claim 22, characterized in that each of said compounds in an oxide powder or an carbonate powder of constituent elements of said compound oxide.

25. A process set forth in Claim 22, characterized in that an atomic ratio of elements in said material powders is adjusted to the same value as and atomic ratio of constituent elements in said compound oxide to be produce.

26. A process set forth in Claim 22, characterized in that said compound oxide is a compound oxide including an element .alpha. selected from IIa group of the Periodic Table, an element .beta. selected from IIIa group of Periodic Table and an element .gamma. selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table.

27. A process set forth in Claim 26, characterized in that said compound oxide is of quasi-perovskite type oxide.

28. A process set forth in Claim 26, characterized in that said element .alpha.is Ba, said element .beta. is Y and said element .gamma. is Cu.

29. A process set forth in Claim 26, characterized in that said element .alpha.is Ba, said element .beta. is La and said element .gamma. is Cu.

30. A process set forth in Claim 26, characterized in that said element .alpha.is Sr, said element .beta. is La and said element .gamma. is Cu.

31. A process set forth in Claim 22, characterized in that said compound oxide is a compound oxide including at least two elements .alpha.1 and .alpha.2 selected from IIa group of the Periodic Table, an element .delta.
selected from Va group of the Periodic Table and an element .gamma. selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table.

32. A process set forth in Claim 31, characterized in that said element .alpha.1 and .alpha.2 is Sr and Ca, said element .delta. is Bi and said element .gamma. is Cu.

33. A process set forth in Claim 22, characterized in that said compound oxide is a compound oxide including at least two elements .alpha.1 and .alpha.2 selected from IIa group of the Periodic Table, an element .epsilon.selected from IIIa group of the Periodic Table and an element .gamma. selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table.

34. A process set forth in Claim 33, characterized in that said element .alpha.1 and .alpha.2 is Ba and Ca, said element .delta. is Tl and said element .gamma. is Cu.

A wire-like composite comprising a compound oxide type superconductor and an outer metal pipe on which said superconductor is supported, characterized in that an intermediate layer made of at least one of metals selected from a group comprising gold, silver, platinum metals and their alloys is interposed between said compound oxide type superconductor and said outer metal pipe.

36. A composite set forth in Claim 35, characterized in that said intermediate layer is made of Ag, Au, Pd, Pt, Rh, Ir, Ru, Os or their alloys.

37. A composite set forth in Claim 35, characterized in that said compound oxide type superconductor is in a form of a layer deposited on the inner surface of an intermediate layer deposited on an inner surface of said metal pipe.

38. A composite set forth in Claim 35, characterized in that said intermediate layer is deposited by sputtering technique.

39. A composite set forth in Claim 35, characterized in that an inner surface of said intermediate layer is further coated with a material which has strong adhesion to said compound oxide type superconductor.

40. A composite set forth in Claim 35, characterized in that said compound oxide type superconductor is in a form of a sintered solid mass compacted inside said intermediate layer.

41. A composite set forth in Claim 40, characterized in that more than one metal wires are embedded in said compound oxide type superconductor.

42 A composite set forth in Claim 35, characterized in that said compound oxide is a compound oxide including an element .alpha. selected from IIa group of the Periodic Table, an element .beta. selected from IIIa group of the Periodic Table and an element .gamma. selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table.

43. A composite set forth in Claim 42, characterized in that said compound oxide is of quasi-perovskite type oxide.

44. A composite set forth in Claim 42, characterized in that said element .alpha. is Ba, said element .beta. is Y and said element .gamma. is Cu.

45. A composite set forth in Claim 42, characterized in that said element .alpha. is Ba, said element .beta. is La and said element .gamma. is Cu.

46. A composite forth in Claim 42, characterized in that said element .alpha. is Sr, said element .beta. is La and said element .gamma. is Cu.

47. A composite set forth in Claim 35, characterized in that said compound oxide is a compound oxide including at least two elements .alpha.1 and .alpha.2 selected form IIa group of the Periodic table, an element .delta.
selected from Va group of the Periodic Table and an element .gamma. selected from a group comprising Ia, IIb, IIb and VIII group of the Periodic Table.

48. A composite set forth in Claim 47, characterized in that said element .alpha.1 and .alpha.2 is Sr and Ca, said element .delta. is Bi and said element .gamma. is Cu.

49. A composite set forth in Claim 35, characterized in that said compound oxide is a compound oxide including at least two elements .alpha.1 and .alpha.2 selected from IIa group of the Periodic Table, an element .epsilon.selected from IIIa group of the Periodic Table and an element .gamma. selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table.

50. A composite set forth in Claim 49, characterized in that said element .alpha.1 and .alpha.2 Ba and Ca, said element .delta. is Tl and said element .gamma. is Cu.

51. A process for producing a wire-like composite comprising a compound oxide type superconductor and an outer metal pipe on which said superconductor is supported, characterized by the steps comprising preparing at least one of material powders selected from a group comprising (i) a powder mixture of compounds each containing at least one of constituent components in the material powder and (ii) a sintered powder of compound oxide prepared by sintering a powder mixture of (ii) and by pulverizing obtained sintered depositing an intermediate layer made of at least one of metals selected from a group comprising gold, silver, platinum metals and their alloys on an inner surface of said outer metal pipe, depositing a layer of said material powder on an inner surface of said intermediate layer, and then heating the metal pipe having said intermediate layer and said material powder layer at a temperature ranging between an upper limit which is defined by a melting point which corresponds to the lowest melting point of any one of constituent components in the material powder and a lower limit which is lower by 100 °C than said upper limit to sinter said material powder inside the outer metal pipe.

52. A process set forth in Claim 51, characterized in that said outer metal pipe is made of Ag, Au, Pd, Pt, Rh, Ir, Ru, Os or their alloys.

53. A process set forth in Claim 51, characterized in that each of said compounds is an oxide powder or an carbonate powder of constituent elements of said compound oxide.

54. A process set forth in Claim 51, characterized in that an atomic ratio of elements in said material powders is adjusted to the same value as an atomic ratio of constituent elements in said compound oxide to be produced.

55. A process set forth in Claim 51, characterized in that said compound oxide is a compound oxide including an element .alpha. selected form IIa group of the Periodic Table, and element .beta. selected from IIIa group of the Periodic Table and and element .gamma. selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table.

56. A process set forth in Claim 55, characterized in that said compound oxide is of quasi-perovskite type oxide.

57. A process set forth Claim 54, characterized in that said element .alpha.
is BA, said element .beta. is Y and said element .gamma. is Cu.

58. A process set forth in Claim 54, characterized in that said element .alpha.is Ba, said element .beta. is La and said element .gamma. is Cu.

59. A process set forth in Claim 54, characterized in that said element .alpha.
is Sr, said element .beta. is La and said element .gamma. is Cu.

60. A process set forth in Claim 51, characterized in that said compound oxide is a compound oxide including at least two elements .alpha.1 and .alpha.2 selected from IIa group of the Periodic Table, an element .delta.
selected from Va group of the Periodic Table and an element .gamma. selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table.

61. A process set forth in Claim 60, characterized in that said element .alpha.1 and .alpha.2 is Sr and Ca, said element .delta. is Bi and said element .gamma. is Cu.

62. A process set forth in Claim 51, characterized in that said compound oxide is a compound oxide including at least tow elements .alpha.1 and .alpha.2 selected from IIa group of the Periodic Table, an element .epsilon.selected from IIIa group of the Periodic Table and an element .gamma. selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table.

63. A process set forth in Claim 62, characterized in that said element .alpha.1 and .alpha.2 is Ba and Ca, said element .delta. is Tl and said element .gamma. is Cu.

64. A process for producing a wire-like composite comprising a compound oxide type surperconductor and an outer metal pipe on which said superconductor is supported, characterized by the steps comprising preparing at least one of material powders selected from a group comprising (i) a powder mixture of compounds each containing at least of constituent components in the material powder and (ii) a sintered powder of compound oxide prepared by sintering a powder mixture of a (ii) and by pulverizing obtained sintered mass, depositing a layer of said material powder on an inner surface of outer metal pipe made of at least one of metals selected from a group comprising gold, silver, platinum metals and their alloys on an inner surface of said outer metal pipe, and then heating the metal pipe having said material powder layer at a temperature ranging between an upper limit which is defined by a melting point which corresponds to the lowest melting point of any one of constituent components in the material powder and a lower limit which is lower by 100 °C than said upper limit to sinter said material powder on the outer metal pipe, so that said compound oxide type superconductor is in a form of a layer supported on the inner surface of the outer metal pipe to provide an axial hollow interior passage in the pipe.

65. A process set forth in claim 64, characterized in that material powder layer is deposited on the inner surface of the metal pipe by sputtering technique.

66. A process set forth in Claim 64, characterized in that each of said compounds is an oxide powder or an carbonate powder if constituent elements of said compound oxide.

67. A process set forth in Claim 64, characterized in that an atomic ratio of elements in said material powder is adjusted to the same value as an atomic ratio of constituent elements in said compound oxide to be produced.

68. A process for producing a wire-like composite comprising a compound oxide type superconductor and an outer metal pipe on which said superconductor is supported, characterized by the steps comprising preparing at lest one of material powders selected from a group comprising (i) a powder mixture of compounds each containing at lest one of constituent components in the material powder and (ii) a sintered powder of compound oxide prepared by sintering a powder mixture of (ii) and by pulverizing obtained sintered mass, depositing an intermediate layer made of at least one of metals selected from a group comprising gold, silver, platinum metals and their alloys on an inner surface of said outer metal pipe, compacting the material powder in an outer metal, and then heating the metal pipe filled with said material powder at a temperature ranging between an upper limit which is defined by a melting point which corresponds to the lowest melting point of any one of constituent components in the material powder and a lower limit which is lower by 100 °C than said upper limit to sinter said material powder inside the outer metal pipe.

69. A process set forth in Claim 68, characterized in that said intermediate layer is made of Ag, Au, Pd, Pt Rh, IR Ru, Os or their alloys.

70. A process set forth in Claim 68, characterized in that each of said compounds is an oxide powder or an carbonate powder of constituent elements of said compound oxide.

71. A process set forth in Claim 68, characterized in that an atomic ratio of elements in said material powders is adjusted to the same value as an atomic ratio of constituent elements in said compound oxide to be produced.

72. A composite set forth in Claim 1, wherein said compound oxide is represented by the general formula:

(.alpha.1-x.beta.x).gamma.yOz in which .alpha. stands for an element selected from IIa group of the Periodic Table, .beta. stands for an element selected from IIIa group of the Periodic Table and .gamma. stands for an element selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table, and a small letter of "x" represents an atomic ratio of .beta. and is a number which satisfies a range of 0.1 ? x ? 0.9 with respect to the total of (.alpha.+.beta.) which is equal to 1, small letters of "y" and "z" represent atomic ratios of .gamma. and oxygen (O) respectively and satisfy ranges of 1.0 ? y ? 4.0 and 1 ? z ? 5 respectively.

73. A composite set forth in Claim 35, wherein said compound oxide is represented by the general formula:
(.alpha.1?x.beta.x).gamma.yOz in which .alpha. stands for an element selected form IIa group of the Periodic Table, .beta. stands for an element selected form IIIa group of the Periodic Table and .gamma. stands for an element selected from a group comprising Ia, IIb, IIIb and VIII group of the Periodic Table, and a small letter of "x" represents an atomic ratio of .beta. and is a number which satisfies a range of 0.1 ? x ? 0.9 with respect to the total of (.alpha.+.beta.) which is equal to 1, small letters of "y" and "z" represent atomic ratios of .gamma. and oxygen (O) respectively and satisfy ranges of 1.0 ? y ? 4.0 and 1 ? z ? 5 respectively.

74. A process set forth in Claims 22, characterized by including further a step of wire-drawing.

75. A process set forth in Claims 22, characterized by including further a step of heat-treatment after the sintered step.

76. A process set forth in Claim 75, characterized in that the heat-treatment is carried out at a temperature ranging from 160 °C to 700 °C.

77. A process set forth in Claim 22, characterized by including further a series of steps comprising sintering, wire-drawing and heat-treatment.

78. A process set forth in Claim 22, characterized by a series of steps comprising compacting the material powder in the metal pipe, drawing the metal pipe filled with the material powder, performing both of sintering of the material powder and removal of the metal pipe, and then cooling the sintered product at a lower cooling speed.

79. A process set forth in Claims 74, characterized in that the wire-drawing is carried out at a dimensional reduction ratio of from 16 % to 92 %.

80. A process forth in Claims 74, characterized by including further a series of steps comprising compacting the material powder in the metal pipe, wire-drawing the metal pipe filled with the material powder, annealing the wire-drawn product, performing intermediate sintering, further wire-drawing the sintered product, and then carrying out the final sintering.

81. A process set forth in Claims 80, characterized by repeating the sequence of the steps comprising the wire-drawing, intermediate sintering and further wire-drawing is repeated for plural times.

82. A process set forth in Claims 81, characterized in that said wire-drawing is carried out by means of dies, roller dies, mill rollers, swaging or extrusion.

83. A process set forth in Claims 74, characterized in that the cooling after the sintering is performed at a cooling velocity of less than 50 °C.

84. A process set forth in Claims 83, characterized in that the cooling after the sintering is performed at a cooling velocity of less than 10 °C.

85. A process set forth in any one of Claims 68 to 72, characterized by including further a step of wire-drawing.

86. A process set forth in Claims 68, characterized by including further a step of heat-treatment after the sintered step.

87. A process set forth in Claim 86, characterized in that the heat-treatment is carried out at a temperature ranging from 160 °C to 700 °C.

88. A process set forth in Claims 68, characterized by including further a series of steps comprising sintering, wire-drawing and heat-treatment.

89. A process set forth in Claims 85, characterized by including further a series of steps comprising compacting the material powder in the metal pipe, drawing the metal pipe filled with the material powder, performing both of sintering of the material powder and removal of the metal pipe, and then cooling the sintered product at a lower cooling speed.

90. A process set forth in Claims 85, characterized in that the wire-drawing is carried out at a dimensional reduction ratio of from 16 % to 92 %.

91. A process set forth in Claims 85, characterized by including further a series of steps comprising compacting the material powder in the metal pipe, wire-drawing the metal pipe filled with the material powder, annealing the wire-drawn product, performing intermediate sintering, further wire-drawing the sintered product, and then carrying out the final sintering.

92. A process set forth in Claims 91, characterized by repeating the sequence of the steps comprising the wire-drawing, intermediate sintering and further wire-drawing is repeated for plural times.

93. A process set forth in Claims 92, characterized in that said wire-drawing is carried out by means of dies, roller dies, mill rollers, swaging or extrusion.

94. A process set forth in Claims 91, characterized in that the cooling after the sintering is performed at a cooling velocity of less than 50 °C.

95. A process set forth in Claims 94, characterized in that the cooling after the sintering is performed at a cooling velocity of less than 10 °C.