Abstract: The combination of one or more high reduction drafts with controlled, low back tensions increases the range of deformation conditions over which dimensional tolerances and Je may be optimized. The method comprises the steps of: first, providing a precursor article comprising a metal matrix surrounding a plurality of filaments extending along the length of the article and comprising precursors to a desired superconducting ceramic; next, roll working the precursor article during a breakdown stage at a back tension less than the elastic to plastic transition threshold of the composite during at least one high reduction roll working draft, and, then, sintering the rolled article to obtain the desired superconducting ceramic. In a preferred embodiment, the rolling step further comprises rolling the article at a front tension less than the elastic to plastic transition threshold of the rolled, unsintered article.

Abstract: Methods for producing biaxially aligned superconducting ceramics are disclosed. The methods include fabricating a composite precursor formed of substantially planar filaments of a superconductor precursor surrounded by a matrix, and thermomechanically processing the precursor to texture at least the interfacial layers with the matrix without converting appreciable amounts of the composite precursor to the superconducting oxide to form a preliminary filament material. The method also includes reaction texturing the preliminary filament material to form and texture a superconducting oxide. Reaction texture involves first heating at relatively low oxygen pressure, then heating at higher oxygen pressure.

Abstract: The inventive method for producing a superconductor is accomplished by longitudinally pulling a metal pipe having a cavity filled with a metal oxide mixture in polycrystalline powder to reduce the outer diameter of the pipe, sintering the metal oxide mixture to form a workpiece, and progressively flattening the workpiece in a succession of pressings. The flattening step is conducted with a pair of coordinately operated clamping jaws, each of which having a work surface which is curvilinear with distinct opposite ends. The clamping jaws are mounted to hinged brackets connected by eccentric arms to rotatable shafts arranged for providing power transmission to the clamping jaws such that, during each of the pressings, each eccentric arm extends at an angle to a respective hinged bracket which is approximately 0° or approximately 180° when power transmission to the workpiece is maximal.

Abstract: A starting material which is converted to a continuous body of an oxide superconductor by a heat treatment is filled in a tubular Ag sheath member. The diameter of the filled member is reduced by extrusion to form a wire. The wire is subjected to a heat treatment so that the starting material inside the sheath member is converted to a continuous body of an oxide superconductor. A superconducting wire constituted by the sheath member and the oxide superconductor filled inside the sheath member is obtained. A superconducting coil can be obtained by winding the superconducting wire.

Abstract: A long oxide superconducting wire for a coil or a cable, manufacturing method thereof, an oxide superconducting coil and a cable conductor which have high operational frequency are provided. The wire is a tape-like oxide superconducting wire including a plurality of filaments of oxide superconductor embedded in a matrix, and each filament is twisted spirally along the longitudinal direction of the tape wire. By winding the wire in a coil, an oxide superconducting coil is obtained. When a plurality of such wires are collected, an oxide superconducting cable conductor can be obtained.

Abstract: A powder in tube method of making an HTc superconductive multifilament strand having a silver-based matrix, in which method:prior to the monofilament step:a composite multilayer material is prepared comprising at least one silver-based sheet, and at least one layer of non-superconductive ceramic material that is permeable to oxygen; andduring the monofilament step, a thickness of composite multilayer material is interposed between first and second thicknesses of silver-based material, thereby forming said first silver-based envelope.

Abstract: This invention provides an oxide-type superconducting flat wire having a critical current density of at least 1,000 A/cm.sup.2, which comprises a Y--Ba--Cu oxide layer having a superconducting property and a silver layer surrounding the oxide layer and has so flat a cross section vertical to the longitudinal direction of the wire that the upper and lower lines between the oxide layer and the silver layers appearing on the cross section having a zone over they are parallel to each other, the thickness of the oxide layer being cold rolled in the range of 0.35 to 0.75 based on the whole thickness of the wire, the whole thickness being 0.2 mm or less, and the metal layer being deformable to follow the shrink deformation of the oxide layer when heat treated to be sintered, but rigid when used.

Abstract: A novel process of the production and processing of high quality, high T.sub.c BSCCO or (Bi,Pb)SCCO superconductors starts with fabrication of a forming a bundle including a plurality of billets, each billet containing at least one filament comprising a dominant amount of an tetragonal BSCCO phase with selected intermediate phases, and substantially surrounded by a constraining metal. The bundle is thermomechanically consolidated to form a multifilamentary precursor article by applying pressure and heat to the bundle under conditions cooperatively selected to cause interdiffusion of said constraining metal at the interfaces between said metal and said filaments and substantially complete elimination of voids in said bundle, and the consolidation step is completed before any high strain longitudinal deformation is performed on the bundle.

Abstract: There are disclosed a high temperature superconductive material which can be plastically deformed, processed optionally into predetermined configurations and industrially mass produced and a method of manufacturing a formed body of the high temperature superconductive material. Mixed is a powder raw material which is mainly composed of: 10 to 50 mol % of at least one amide or nitride of alkali metal of Li, Na or K; 10 to 60 mol % of cyanide containing at least one metal selected from aluminum, copper, silver or gold; 5 to 50 mol % of at least one pure metal selected from aluminum, copper, silver or gold; and 10 mol % or less of at least one alkaline earth metal selected from Be, Mg, Ca, Sr or Ba. The powder raw material is pressed, and heated and sintered at the temperature of 673 K to 1553 K. In this manner, obtained is the plastically deformable high temperature superconductive material which can be optionally processed through forging, rolling and the like.

Abstract: A high temperature superconductor composite material, which is suitable for production of filaments, wires, coils and other shaped products, has a ceramic powder of a material selected from the group consisting of, for example, YBa.sub.2 Cu.sub.3 O.sub.7-x and Bi.sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10 ; a solution of a material selected from the group consisting of rubber silicone or lacquer silicone in a substance selected from the group consisting of toluene or acetone; and an ultra-fine silver powder dope, and is produced by using an emulsion mixture of the three major components with ultrasonic homogenization of the mixture, primer cladding of a glue-exterior layer on a silver core filament, high temperature superconductor coating of the silver core by chemical adhesion, and polymerization of the coating applied by low temperature heating, whereafter the composition is treated by magnetic treatment, gamma irradiation, and microwave supported fast heating.

Abstract: A method of forming a textured superconductor wire includes constraining an elongated superconductor precursor between two constraining elongated members placed in contact therewith on opposite sides of the superconductor precursor, and passing the superconductor precursor with the two constraining members through flat rolls to form the textured superconductor wire. The method includes selecting desired cross-sectional shape and size constraining members to control the width of the formed superconductor wire. A textured superconductor wire formed by the method of the invention has regular-shaped, curved sides and is free of flashing. A rolling assembly for single-pass rolling of the elongated precursor superconductor includes two rolls, two constraining members, and a fixture for feeding the precursor superconductor and the constraining members between the rolls.

Abstract: A process for manufacturing a superconducting elongated article such as a superconducting wire which is applicable for manufacturing a superconducting coil or the like. The process includes steps comprising filling a metal pipe with material powder of ceramic consisting of compound oxide having superconductivity, performing plastic deformation of the metal pipe filled with the ceramic metal powder to reduce the cross section of the metal pipe, and then subjecting the deformed metal pipe to heat-treatment to sinter the ceramic material powder filled in the metal pipe. The ceramic material powder may contain compound oxide having Perovskite-type crystal structure exhibiting superconductivity.The metal pipe may selected from a group comprising metals of Ag, Au, Pt, Pd, Rh, Ir, Ru, Os, Cu, Al, Fe, Ni, Cr, Ti, Mo, W and Ta and alloys including these metals as the base. The heat-treatment may be carried out at a temperature ranging from 700 to 1,000.degree. C.

Abstract: Superconducting articles and a method of forming them, where the superconducting phase of an article is Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.y (Bi-2212). Alumina is combined with Bi-2212 powder or Bi-2212 precursor powder and, in order to form an intimate mixture, the mixture is melted and rapidly cooled to form a glassy solid. The glassy solid is comminuted and the resulting powder is combined with a carrier. An alternative to melting is to form the mixture of nanophase alumina and material having a particle size of less than about 10 microns. The powder, with the carrier, is melt processed to form a superconducting article.

Abstract: An oxide superconductor wire is prepared by preparing a length of precursor wire for processing into an oxide superconductor wire and coating the precursor wire with an isolating layer. The coated wire is wound onto a reel in a spiralling manner, such that each turn of the spiral is in alignment with the preceding turn of the spiral along an axis perpendicular to the axis of winding. The wound precursor wire is then heated to form the oxide superconductor. The removable isolating layer is prepared by coating the wire with a solution including a metal oxide and a porosity-inducing component, and heating the coated wire so as to induce porosity and control grain size of the metal oxide so as to render the coating removable. The coating should function to isolate the overlapping turns of the wound wire from neighboring wires, so that not diffusion bonding or adherence between the turns occurs.

Abstract: A novel process of the production and processing of high quality, high T.sub.c (Bi,Pb)SCCO superconductors starts with fabrication of a precursor article including selected intermediate phases with desired chemical and structural properties. The precursor fabrication includes introducing the reacted mixture having a dominant amount of the tetragonal BSCCO phase into a metal sheath, and sealing the reacted mixture within said sheath, heating the mixture at a second selected processing temperature in an inert atmosphere with a second selected oxygen partial pressure for a second selected time period, the second processing temperature and the second oxygen partial pressure being cooperatively selected to form a dominant amount of an orthorhombic BSCCO phase in the reacted mixture.

Abstract: A superconducting oxide wire and a method of manufacturing the same are disclosed. The wire comprises a pipe made of a metal and a superconducting oxide material filling the interior of the pipe and comprising superconducting oxide grains which are bonded to each other and which have a perovskite crystal structure having a C face and a C axis. The superconducting oxide grains contain more than 50 vol % of plate-shaped grains of which the length in the direction of the C face is greater than the length in the direction of the C axis. The C faces of most the plate-shaped grains are arranged to be directed toward longitudinal axis of the pipe.

Abstract: A method of producing a tape-shaped superconducting wire is provided. The wire maintains a high critical temperature and a high critical current density along the overall length thereof. In this method, raw material powder for the oxide superconductor is first charged in a silver sheath and the sheath charged with the powder is subjected to plastic working to prepare a first flat type wire. On the other hand, a second wire consisting of a tape wire formed by coating a surface of a flat type wire having at least an outer surface consisting essentially of silver or a silver alloy with a metal oxide or ceramics, or a tape wire containing ceramics fibers and a binder dissipated by heat treatment is prepared. The first and second wires are layered with each other, and tightly wound in a pancake coil shape. The wires wound in the pancake coil shape are heat treated for sintering the oxide superconductor. After the heat treatment, the first wire is separated from the second wire.

Abstract: A superconductive composite member, which has a core composed of an oxide ceramic material which is surrounded by an envelope, has an increased core density in order to achieve a higher critical current density. The increased core density is obtained during a hot-shaping step of the core material in the envelope, wherein the composite is heated to a temperature wherein the superconductor material is present in either a molten or a partially molten state.

Abstract: A low-aspect ratio multi-filament superconductor wire includes a plurality of oxide superconductor filaments arranged in an elongated wire structure. Each filament of the wire also has a low-aspect ratio. The filaments are textured such that a crystallographic c direction of each filament is aligned with a crystallographic c direction of all other filaments with the crystallographic c directions being perpendicular to the longitudinal axis of the wire structure. The invention also features a groove rolling machine for forming a low-aspect ratio multi-filament superconductor wire by texturing a precursor tape by deforming the tape to a low-aspect ratio wire by reducing a larger dimension of the tape in such a way as to prevent buckling of the tape. A superconducting cable can be formed by planetary winding a plurality of multi-filament superconductor wires.

Abstract: Disclosed herein is a method of preparing a bismuth superconductor including the steps of mixing raw materials for forming a bismuth superconductor with each other to obtain mixed powder, heat treating the mixed powder, pulverizing the mixed powder and then covering the mixed powder with a metal sheath. The mixed powder covered with the metal sheath is prepared to have a 2223 composition in a composition of Bi--Sr--Ca--Cu or (Bi,Pb)--Sr--Ca--Cu and to contain a superconducting phase which is mainly composed of a 2212 phase, and is pulverized into a mean particle diameter of not more than 1 .mu.m with no conversion of the 2212 phase to an amorphous state.

Abstract: A superconducting tape or wire with a longitudinally extending outer layer of Ag or its alloys defining an inner region, an area of Ag or its alloys in said inner region extending longitudinally of said tape or wire separated from said outer layer of metal by freeze dried superconducting material. The inner Ag area may be a rod, a tube or a number of wires. The superconductor material is preferably B-2223.

Abstract: A method for forming a conductor element comprising a Tl or Hg-based high temperature superconductor (HTSC) material, comprises providing at least one first precursor material within an outer sheath for the conductor element; providing at least one second precursor material within the conductor sheath and separated from the first precursor material(s) by a barrier layer formed from a Noble metal for example between the first and second precursor materials; and heating the conductor sheath containing the precursors to a temperature at which the barrier layer melts to allow the precursor materials to mix and react, or to a temperature at which one of the precursor material(s) diffuses through the barrier layer sufficiently allow the precursor materials to mix and react, to form the Tl or Hg-HTSC material within the outer conductor sheath.

Abstract: A method of producing a superconductive coating (19) on an elongated substrate (12) is indicated, whereby the substrate (12) is drawn through a deposition chamber (1) in which it is also heated in a heating zone (2) and is coated with a superconducting material. To improve the current carrying capacity, the substrate (12) is coated with the superconducting material in a geometric form which differs from the use of the finished product in a way so that a compressive strain is created in the substrate plane of the superconductive coating (19) for the geometric form of the substrate (12) taking place when it is put to use.

Abstract: A process for manufacturing a superconductor. The process is accomplished by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon, overlaying a continuous length of a second substrate ribbon on said first substrate ribbon, and applying sufficient pressure to form a bound layered superconductor precursor between said first substrate ribbon and said second substrates ribbon. The layered superconductor precursor is then heat treated to form a super conductor layer.

Abstract: A (BiPb).sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x (Bi223) superconductor with high J.sub.c, phase purity, density and mechanical strength is formed from Bi2223 powder which is synthesized from a mixture of Bi.sub.2 O.sub.3, PbO, SrCO.sub.3, CaCo.sub.3 and CuO. The mixture is milled, then dried and calcined to synthesize the Bi2223 powder with the desired phase purity. The calcination is performed by heating the dried mixture for 50 hours at 840.degree. C. The partially synthesized powder is then milled for 1-4 hours before calcining further for another 50 hours at 855.degree. C. to complete the synthesis. After calcination, the Bi2223 powder is cold pressed to a predetermined density and sinter forged under controlled temperature and time to form a Bi2223 superconductor with the desired superconducting properties.

Abstract: In order to obtain a Bi--Sr--Ca--Cu--O or Bi--Pb--Sr--Ca--Cu--O oxide superconducting wire, raw material powder is pulverized to remove particles of non-superconducting phases having large particle sizes based on difference in particle size, and thereafter the raw material powder is covered with a sheath of silver or silver alloy, so that the sheath is subjected to plastic working and the raw material powder covered with the sheath is sintered.

Abstract: A process for manufacturing a wire made of oxide which is applicable for manufacturing a superconducting coil or the like. The process includes steps comprising preparing a mass of oxide having superconductivity from powder material, covering the mass of oxide with a metal pipe, and then reducing the diameter of the metal pipe containing the mass of oxide therein into a wire form by such plastic deformation that exert mainly compressive strain upon the metal pipe. The mass of oxide may be a compound oxide having Perovskite-type crystal structure exhibiting superconductivity. The metal pipe may be made of a metal selected from a group comprising Cu, Al, Nb, V, Mo, Ta, and Ag and of an alloy including these metals as the base. The mass of oxide may be produced by steps including extruding a powder material into a rod shape and then sintering the molded rod at a temperature ranging from 700.degree. to 1,000.degree. C.

Abstract: In a method of preparing a thallium oxide superconductor having components of Tl-Bi-Ca-Sr-Cu-O or Tl-Bi-Pb-Ca-Sr-Cu-O from raw material powder, the raw material powder is subjected to first heat treatment, then exposed to a compressive load, and thereafter subjected to second heat treatment. Thus, a thallium oxide superconductor having a high critical current density can be obtained.

Abstract: A new design for an aluminum stabilized superconductor which embeds the superconducting cable within a high purity aluminum stabilizer. This stabilizer is, in turn, partially surrounded by an aluminum alloy sheath. The aluminum alloy sheath is constructed and arranged so that at least one exterior surface of the stabilizer is open for exposure to a coolant. Preferably, this open exterior surface of the stabilizer will be knurled for greater cooling efficiency.

Abstract: A holder (1) provided with a spirally extending groove (2) is prepared and an oxide superconducting wire (3) is arranged in the groove (2) to be heat treated, so that each portion thereof is not bonded to another portion during the heat treatment.

Abstract: A continuous method for manufacturing an elongated superconducting campsite composed of a superconductor consisting of compound oxided and a metal sheath surrounding the superconductor, including the steps of kneading a material powder of superconducting compound oxide with a binder, continuously shaping the resulting kneaded paste into an elongated pre-form by an extruder or by coating technlque, heating the pre-form continuously to remove said binder, wrapping the pre-form with a metallic sheet, and then subjecting the pre-form from wrapped with the metallic sheet to sintering operation to sinter said material powder.

Abstract: A strongly-linked polycrystalline oxide superconductor article includes an oxide superconductor selected from the group consisting 124-type and 247-type oxide superconductors having fine, highly aligned oxide superconductor grains less than 50 .mu.m along a longest dimension. The oxide superconductor article has at least a 25% retention of critical current density in a 0.1 Tesla field.

Abstract: A system and method for mechanically forming a ceramic superconductor product. A system for making the ceramic superconductor includes a metallic channel portion having a cross section for receiving a ceramic superconductor powder, a roll to mechanically reduce the channel cross section and included superconductor powder and a cap portion welded to the channel portion using a localized high energy source. The assembled bar is then mechanically reduced to form a tape or wire end product.

Abstract: A method of producing a Bi-Pb-Sr-Ca-Cu oxide superconductor by thermally treating raw material comprises steps of performing first plastic deformation on the raw material, performing first heat treatment on the material being subjected to the first plastic deformation, performing second plastic deformation on the material being subjected to the first heat treatment, and performing second heat treatment on the material being subjected to the second plastic deformation.

Abstract: In order to obtain a ceramics system superconducting wire, a bulk type ceramics system superconductor or its precursor previously treated to have orientativity in its crystal structure is reduced in diameter in a state charged in a metallic pipe, thereby being elongated, and then heat treated. In the as-formed superconducting wire, crystal orientativity of a bulk formed of the superconductor or its precursor is maintained, whereby it is possible to obtain a superconducting wire having high critical current density. In order to further improve the critical current density, it is effective that the diameter reduction working step and the heat treatment step are alternately repeated a plurality of times.

Abstract: In a method of preparing a bismuth oxide superconducting wire comprising the steps of filling raw material powder into a metal sheath, working the same into a wire by performing deformation processing in this state, and heat treating the wire, the raw material powder is heat treated before the step of working the raw material powder into a wire by performing deformation processing, so that the ratio of a 2212 phase, containing Bi or (Bi,Pb), Sr, Ca and Cu in composition ratios of about 2:2:1:2, to a 2223 phase, containing Bi or (Bi,Pb), Sr, Ca and Cu in composition ratios of about 2:2:2:3, is 75 to 90:10 to 25, in order to prepare a wire which is excellent in critical current density as well as in critical current.

Abstract: Two-powder processes for the synthesis of superconducting (Bi, Pb)-2223/Ag-clad wires by the oxide-powder-in-the-robe are provided. The first precursor powder, of nominal stoichiometry CaCuO.sub.x, is a solution-synthesized mixture of Ca.sub.0.45 Cu.sub.0.55 O.sub.2 and CaO. Using these oxide precursor mixtures, superconducting tapes with well-aligned grains and reproducible critical current densities J.sub.c in the range of 20,000 to 26,000 A/cm.sup.2 at 75 K in self-field after annealing less than 200 hours were obtained.

Abstract: Powder having a composition in which the contents of Sr, Ca and Cu are increased so that an Sr-Ca-Cu-O phase is precipitated in addition to a 2223 phase of (Bi, Pb)-Sr-Ca-Cu is charged in a metal sheath, and this metal sheath is plastic-worked, then subjected to a primary heat treatment, then plastic-worked and further subjected to a secondary heat treatment. In the as-obtained bismuth oxide superconducting wire, pinning points based on the Sr-Ca-Cu-O phase are introduced into the superconductor, whereby magnetic field characteristic of the critical current density is improved.

Abstract: A method of forming a crepe paper insulated superconducting magnet coil with fifty percent overlap crepe paper wrapping with the paper wound superconductor subsequently wound into a coil on a coil form pocket using the crepe paper wrap as an insulating and friction reducing component.

Abstract: A method of producing a high temperature long length coil of superconductor wire or tape having improved critical current densities by utilizing an in-line pressing operation to heal the microcracks in the tape or wire which were introduced in rolling and coiling operations. The material can be Bismuth-2223, Bismuth 2212, Thallium-1234 or any other high temperature superconducting material. In the case of the Bismuth-2223, an improved "powder-in-tube" processing operation is provided to utilize excess bismuth, calcium, and copper in the initial composition material, and forming a partially developed Bi-2223 phase in the precursor powder introduced into the silver tubes. The final product has a 90-100% Bi-2223 phase with fine dispersions of secondary phases, to provide improved flux pinning thereby improving the critical current density of the material.

Abstract: A method of preparing a superconducting oxide by combining the metallic elements of the oxide to form an alloy, followed by oxidation of the alloy to form the oxide. Superconducting oxide-metal composites are prepared in which a noble metal phase intimately mixed with the oxide phase results in improved mechanical properties. The superconducting oxides and oxide-metal composites are provided in a variety of useful forms.

Abstract: An oxide superconducting coil is formed by winding a superconducting multifilamentary wire consisting essentially of a plurality of filaments consisting essentially of an oxide superconductor and a stabilizing material, consisting of silver or a silver alloy, covering the filaments. Superconducting phases of the filaments are substantially rendered monophasic, and c-axes thereof are strongly oriented along the thickness of the wire. Crystal grains of the superconductor forming the filaments are in the form of flakes extending longitudinally along the wire, while the same are bonded to each other. In a section of the wire, a ratio obtained by dividing a sectional area occupied by the silver or the silver alloy by that occupied by the filaments is not more than 3. In a magnetic field of at least 10 T, the coil exhibits a critical current value which is at least 60% of that exhibited by the wire itself forming the coil.

Abstract: Disclosed herein is a method of preparing an oxide superconducting wire comprising the steps of coating a powder material for forming an oxide superconductor with a metal, performing deformation processing on the metal-coated powder material thereby obtaining a tape-type wire material, superposing a plurality of such tape-type wire materials, performing first heat treatment on the plurality of superposed tape-type wire materials while simultaneously diffusion-bonding the metallic coats to each other, then performing deformation processing on the plurality of superposed tape-type wire materials, and performing second heat treatment on the plurality of deformation-processed tape-type wire materials. Preferably the oxide superconductor to be obtained is a bismuth oxide superconductor having a 2223 composition in a composition of Bi-Sr-Ca-Cu or (Bi,Pb)-Sr-Ca-Cu, and the powder material consists of a superconducting phase, which is mainly composed of a 2212 phase, and non-superconducting phases.

Abstract: A composite superconducting wire using ceramic superconductor material in which one or more elongated superconductor material are accommodated in one or more grooves formed on an elongated reinforcing member so that a long size superconductor wire can be provided. Various methods of producing such composite superconductor wire are also disclosed.

Abstract: A method for manufacturing an elongated member from a superconducting ceramic material comprising the steps of providing a hollow supporting body of metal or a metallic alloy having a hollow inside section therein, introducing a superconducting ceramic material into the hollow inside section of the hollow supporting body, drying the above liquid, so that the superconducting ceramic material is coated on the inside of the supporting body; and firing the supporting body and the ceramic material in an oxidizing atmosphere.

Abstract: In order to prevent inflation of a metallic coating during heat treatment so that no ununiformity is caused in the critical current density in a method of preparing an oxide superconducting wire which is obtained by heat treating and sintering metal-coated raw material powder for an oxide superconductor, raw material powder (5) for an oxide superconductor is filled up in a metal billet (1), which in turn is degassed and sealed in the degassed state, elongated with application of hydrostatic extrusion, and then heat treated.

Abstract: A method of preparing a superconducting oxide by combining the metallic elements of the oxide to form an alloy, followed by oxidation of the alloy to form the oxide. Superconducting oxide-metal composites are prepared in which a noble metal phase intimately mixed with the oxide phase results in improved mechanical properties. The superconducting oxides and oxide-metal composites are provided in a variety of useful forms.

Abstract: In a method of preparing an oxide superconducting wire comprising the steps of filling up raw material powder for an oxide superconductor in a metal sheath and rolling the same in this state, frictional force on surfaces of rolls employed for rolling is increased in the rolling step in order to improve denseness of the raw material powder, thereby improving the critical current density of the oxide superconducting wire. In order to increase the frictional force, films having large frictional force are formed on the roll surfaces, a coating material is applied to the roll surfaces during rolling, or the roll surfaces are roughened, for example.

Abstract: A method of producing a high temperature long length coil of superconductor wire is disclosed. The method utilizes the "powder-in-tube" method or a similar method to form a wire. The wire is then shaped into rectangular form and wound around a mandrell. Rings, having a gap exposing the superconductor inside the silver or silver alloy tube are formed by cutting the wound wire and the rings are pressed to their final thickness. Each ring is then coated with an insulator and filed on both an outer side of one end of the gap and on an inner side of the other end of the gap. The rings are then positioned adjacent one another such that the gaps are staggered. They are placed in a manner in which the exposed superconductor on an outer side of one ring is in contact with the exposed superconductor on the inner side of an adjacent ring. The rings are then clamped together and heated to merge the superconducting material by diffusion. A long length coil is thus formed from the rings that are clamped.

Abstract: A superconductive article is made by inserting a rigid mandrel into an internal cavity of a first metallic tube, said tube having an interior surface and an exterior surface, said interior surface defining the interior cavity, forming a layer of a superconductive material or superconductive precursor upon the exterior surface of said first metallic tube, machining the layer of superconductive material or superconductive precursor to a predetermined diameter to form an intermediate article configured for insertion into a second metallic tube having an interior diameter corresponding to the predetermined diameter, inserting the machined intermediate article into a second metallic tube having an internal diameter corresponding to the predetermined diameter of the intermediate article to form a composite intermediate article, reducing or ironing the composite intermediate article to a predetermined cross-sectional diameter, and sintering the reduced or ironed composite intermediate article at temperatures and for