JPH06510157A - Textured superconductor and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates generally to superconducting materials, and more particularly to textured superconducting oxide objects and and a method for its production from metal precursors. The invention also provides enhanced electrical properties. It also relates to multifilamentary superconducting oxide bodies having

Superconductors have an intrinsic zero-point resistance to electron flow at temperatures below their critical temperature Tc. It is a substance that has Certain metal oxides have a temperature of 10°K (degreeK It is known that it exhibits superconductivity at relatively high temperatures, exceeding the There is. For example, one group of known superconducting metal oxides has the general formula: La2-1M ACu 04-v, where M is an alkaline earth element such as Ba, Sr, etc.

Other groups include, but are not limited to: (1) R-BahCucO y (wherein R is Y', Yb, Er, Ho, Eu, Dy, Gd.

One or a combination of La, Pr, Sm, Nd, Ca or a rare earth element subscripts a, b, c can be 1:2:3.2:4 near, 1:2:4, or is more generally n: 2n: 3n-1-1 (n=1.2.3...) (within the ratio of ); (2) (M+-xQ-)nLhcaecuaoy (where M is Bi and/or Q can be one or a combination of TI; Q can be pb, sb. ;L is Sr.

Can be one or a combination of Ba or alkaline earth species; x-0 Or x>0; the ratio of a:b:c:d is 2:2:n:n+1.1:2:n:n+1. 11・n: n+1 and 2・1・n: n+1 (n=1.2.3...) (within the ratio range).

(3) Pb, Sr, M, Cu, 0. (In the formula, M is Y, La, Pr, Nd1Eu, Dy.

HOlTm, Lu or pond rare earth elements, 5rSCa or other alkaline earth elements. one or a combination; the ratio of a:b:c:d may be 2:2:1:3. can).

(4) BaPb, −, Bi, o3 (x>O); and (5) Ba, +−+B 1 o3(x>0).

Each of the F metal oxides contains oxygen, but the "oxide" used here does not necessarily mean oxygen. It should be noted that this does not include Oxidation is the process whereby a metal element has a lower valence. It is the process of converting a state to a higher valence state. an element with at least one atom A high valence state is obtained when a valence electron is lost. Therefore, here we use oxide and is defined as a compound in which the metal species is placed in a high valence state. Examples of oxides includes, but is not limited to, sulfides, halides, carbides, nitrides, carbonates, and metal-oxygen compounds. Metals or alloys are exposed to oxidizing atmospheres (e.g. , 02, S2, N2, or CO2). can be done. They can also be oxidized by applying an electric potential. I can do it.

Superconducting oxides, which generally correspond to oxides, are g) susceptible to brittle fracture during the process; N., McN., Alford, J., D., Birc. hall, ~V.J., Clegg, M.A., Harmer, Kendall I. Andri,! (, Jones, “Physical and Mechanica lProperties of YBa2Cu307-. 5uppercondu ct.

rs''J~fat, Sci, Volume 23, Issue 3, Pages 761-8, 1988゜Choden The conductivity of conducting oxides decreases when cracks are present in the conducting path, so The reduction in the propagation tendency of cracks in Become.

Oxide-metal composites are more susceptible to catastrophic brittle failure than pure oxides is low. crack plinonong, crack deflection, crack planting (bluntih) g) Improved mechanical properties of oxide-metal composites, including crack nodes Several theories have been proposed to explain quality. F., Erdogan, P.F. , Joseph, “Toughening of Ceramics ugh Crack Bridging by Ductile Partia les'' J, Am, Ceram, Soc, Vol. 72, No. 2, pp. 262-70.

1989;, ”＼　G, Evans, R.M., McMeeking, “On the Toughening of Ceramics by Strong "Reinforcements" Acta Metal, Volume 374, Issue 12 , pp. 2435-2442, 1.986: Andori, S, 51g1. P, A, Mat aga, B.

J, Dalgleish, R, M, McMeeking, and A, G, Ev. ans,+On the Toughness of Br1ttle Mat erials Re1nforced with a Ductile Pha se”, Acta Metal, Vol. 36, No. 4, pp. 945-953, 1988 ゜According to these theories, the fine structure and morphology of the oxide-metal composite are Determine the crack propensity of coalescence. For example, crack propagation resistance due to crack bridging mechanism The microstructure, which is particularly effective in strengthening the It is a complex consisting of interconnecting metal particles.

One method for producing a superconducting oxide-metal composite is to first obtain a desired superconducting oxide. forming a precursor alloy comprising a metal element of the object and at least one other metal; oxidation of the alloy to form a superconducting oxide. (For example, refer to here Related references include U.S. Pat. No. 4,826,808 to Yurek et al. Reparation of Superconducting Oxides and Oxide Metal Composites).

Noble metal elements whose oxides are thermodynamically unstable under the reaction conditions used to oxidize the alloy It is a noble metal in the sense that it is a precious metal). Alloys containing precious metals , converting certain metal elements in alloys into superconducting oxides without oxidizing the precious metals Can be oxidized under certain conditions. Precious metals are present in fine powder form rather than as a secondary oxide phase. actually precipitates as a pure metallic phase. Therefore, noble metals are superconducting oxides and intimately mixed, thereby modifying the mechanical properties (e.g. strength, ductility) of the composite. Good.

Generally, the fracture toughness of oxide/metal composites increases as the amount of metal in the composite increases. increase However, increasing the volume fraction of metal decreases the volume fraction of superconducting oxide. and reduce the supercurrent carried by the complex. be able to. If the amount of metal becomes large enough, it will pass through the superconducting oxide particles. A continuous conduction path cannot be maintained and the composite is no longer superconducting.

Therefore, it is important to optimize the amount of metal phase in a composite with randomly distributed metals and oxides. A trade-off must be made between superconductivity and mechanical properties when .

The morphology of the oxide and metal components at a given volume fraction of the metal also affects the electrical properties of the composite. plays an important role in determining quality. As mentioned above, to form a continuous conducting path The oxide particles must be sufficiently atomized, otherwise the composite will not carry overcurrent. Do not transport. Furthermore, the orientation of the oxide particles affects the electronic properties of the composite.

More specifically, in materials in which oxide particles are crystallographically oriented in a preferred direction, , the critical current of superconducting oxide is large.

For example, highly oriented thin films of YBa2Cu307-r are (“T”) at 77 degrees Kelvin (“K”), respectively. Transport critical field densities of 4xlO5 and 6.5xlO'A/cm2 are shown. this The superconducting oxide particles in such a film have a crystallographic C perpendicular to the plane of the film. Orient in the direction. K, Watanabe, H, Yamane, H, Kurosa. wa, T, H4ra　i, N, Kobayas　i,)L　Iwasaki,to , Noto and Y, Muto, “Crltical Currents at 77.3 Kunder Magnetic Fields up to 27T foran Y-Ba-Cu-OFilm Prepared by Che mical Vapor Deposition”, Appl, Phys, Le tt.

, vol. 54, no. 6, p. 575, 1989o, highly oriented Bt2,5r2ca, Cu　20. The thin film of A transport current density of 105 A/cm2 is produced at 61 K. M.Hong. J, KwO and J, J, Yeh, “High Crltical Current t Superconducting B1-3r-Ca-Cu-OFilm s”, Appl, Phys, Lett,, 1988°’r’Ba2Cu30y- The bulk crystallographic orientation of ``multi-textured growth'' It is manufactured by a directional solidification process known as

Such oriented bulk superconductors are observed at 77 K in the applied magnetic fields of OT and IT. transport critical electric field densities of 1.7xLO'A/cm2 and 4x103A/cm2, respectively. degree (Jc). S, J in, T, H, Tiefel, R, C, S herwood, R, B, van DoverlM, E, Davis, G, W , Kammlot, R.A., FaStnaCht and H.D., Keit h, App 1Phys, L, ett, 521.2074 pages, 1988° In contrast, the bulk non-oriented materials of YBa, Cu, and O□-3 are At 77K, it produces a critical electric field on the order of only 102-103 A/cm2. It's working. The Jc value of such non-oriented YB a2Cu sO7 is determined by the magnetic field. shows an obvious decrease when . J, MSeunt jens, D, C, Larb alestier, J. Appl, Phys, vol. 67, 1990.2007 page. Therefore, it is preferred to form crystallographically oriented superconducting oxide bodies.

Possible explanations for the improved electrical performance of preferred crystallographically oriented superconductors One is a reduction in structural irregularity at grain boundaries. Dirnos etc. are YBa2C Critical electric potential across grain boundaries in the bicrystal of u3307-r As the flow density increases the particle misorientation angle increases. I have observed that it decreases over time. The reduction in critical current due to misorientation of particles is The increase in structural irregularity at the grain boundaries in turn reduces the overcurrent across the grain boundaries. it is conceivable that. D., Dimos, P., Chaudhari, J., Mannhar. t and F.

K. LeGoues, “Orientation Dependence of Grain Boundary Cr1tical Currents 1nY Ba2Cu30 Fu-, Bicrystals”, Phys, Rev, Lett, .

61, No. 2, p. 219, 1988 and D.C., Larbalestier, S. .

E., Babcock, X., Cai, L., Cooley, M., Daemling.

D. P., Hamshire, J. Mckinnell and J. M. 5euntj. ens, Tokai University Superconductivity Newsletter, Woid 5 scientificP ress, November 1988. There is anisotropy in the superconductivity of high Tc oxides, and The maximum overcurrent flows in the direction located within the crystallographic a-b plane of the conductive oxide particles. It is also known that Therefore, misalignment between adjacent particles (misal i　gnmen　t) degree is minimum, and the crystallographic a-b plane of the grain is Superconducting oxide oriented to align in the direction required for practical use Preferably, a superconductor with particles is obtained.

Y　B　a　2Cu　307-The superconductor has a long dimension in the C direction, as shown in Figure 1. It consists of a crystalline unit cell with short dimensions in the C and b directions. this crystal So, the C dimension is about 1. ],, 7 x 10-”m, and the 5 dimensions are approximately 3.88 xlO-10m, and the 8 dimension is approximately 3.82xlO”m.The C dimension of the unit cell is The length of the modulus is approximately three times the length of the a and 5 dimensions. Based on Pb-B1-5r-Ca-Cu-0 High-temperature superconductors are similar in that their unit cells have a longer C dimension than other dimensions. It is.

Superconductor based on Y-Ba-Cu-0 and Pb-Bi-3r-Ca-Cu- 0-based superconductor, the superconducting oxide particles are parallel to the a-5 plane of the unit cell. A crystal structure that grows relatively long in the C direction and relatively short in the C direction. It is known that anisotropy in chemical growth rate exists. (Thus, the unit cell length The short dimension becomes the short dimension of the oxide particle. ) In other words, the growth of superconducting particles is It is fastest in the a-b direction, not in the C direction. This growth anisotropy is shown in Figure 2. Aspected grains with thin dimensions as schematically shown give birth to a child. It should be noted that FIG. 2 is not drawn to scale.

Minimizes the total free energy associated with grain boundaries during annealing and normal grain growth It is also known that larger particles tend to consume smaller particles in order to Ru. Ni, Hi Iert, Acta, Met, vol. 13, p. 227, 19 During 65° oxidation/annealing, the growth of high Tc superconducting oxide particles lasts for 1 day. Compressed in Jiyon (dimens ion) or 2 daymen noyon has the longest dimension if it is done without compression in other dimensions. The particles formed are fast-growing crystallographic structures parallel to the “unsqueezed” dimension. These are particles oriented in the target direction (direction parallel to the a-5 plane of the high Tc oxide). mentioned above As shown in Fig. 2, a fast-growing a-b plane of particles aligned parallel to the direction of the bulk current It is desirable to obtain a high Tc oxide superconductor that has a high Tc. flat on the preferred daymenyon Particles oriented in the a-5 plane grow relatively long, which is similar to normal particle growth. The process produces small particles with limited length that are not oriented in this way. will eventually be consumed, thus effectively limiting the anisotropic growth of high Tc oxide particles. By this, preferred particle alignment can be obtained. (This statement and as used within the scope of the claims, the "length" of an oxide particle refers to the size of the particle's largest dimension. It means z. ) superconducting oxides with limited dimensions other than the direction of bulk current One of the known methods for obtaining the structure of oxide filaments by a method known as ``wder-in-tube'' The goal is to manufacture products. In this method, superconducting oxide powder is placed in a tube, usually made of silver. Put it in. After sealing, transform the filled tube into a thin ribbon or thin wire. Ru. This deformation step is usually followed by a high temperature anneal to sinter the oxide particles.

Unfortunately, this method results in thin ribbons or wires with uniformly thin cores. is difficult to obtain. For example, Osamura et al. Silver sourced (si 1ver-sheathed) Pb with oxide core - To obtain the Bi-3r-Ca-Cu-0 tape, it is possible to guarantee the “uniform purchasing deformation”. K,Osamura,S,Oh,S,0cb ia1. “Effect of Thermomechanical Tre atment on the Cr1tical Density of Ag 5heatedB(Pb) SCCOTapes”, 5upperconduct or 5science and Technology, Volume 3, 1990.14 3 pages. The reason for such heterogeneous deformation is that the brittle oxide core and ductile metal sheath are It behaves differently in its shape. Superconducting oxides are as low as 10-4 s-1. Even at high strain rates and temperatures of 800°C, e manner) is known to be deformed. M. J., Kramer, L. S, Chumbley, R, W, Nic Callum, “Analysis” of DeformedYBa2Cu30□-,-,J, of Mat, Sci , 1989, silver is ductile ( in a ductile manner). This difference in deformation behavior contributes to the brittle core. This creates a local flow stress gradient between the ductile source and the oxide/metal composite. Limits the processability of the tube. RN, Wright, R, M, German, D, B , Knorr, R., MacCrone, Rajan and W.Z., Mis. iolek, “Mechanical Con5iderations im the Processing of High Tc 5uppercondu ctors+, February 21, 1990, T in Anaheim, California Presented at MS annual meeting.

Very fine and uniform superconductor filaments form low-temperature metallic superconductors (high-temperature oxide superconductors). manufactured by the transformation of metal precursors as wires (to distinguish them from conductors) There is. For example, the “bronze” method replaces the niobium rod with a larger diameter bronze rod. into the axial hole drilled inside. H, Hi I 1mann, “Fabr 1cation Technology of Superconducti ngMaterials", 5superconductor Material sScience: Metallurgy, Fabrication, and Appl 1cat 1ons, edited by S, Foner, B, B, Schwartz Collection, PIenum Press, New York, 342 pages. This bronze-niobium composite Extrude the assembly to the appropriate diameter. Bundle such composite rods and make another bronze into the tube and process the tube again. Next, this multifilamentary composite When Sn (tin) is supplied as a low-temperature superconductor and bronze by annealing, Nb3 Sn.

Manufacture. Such a method produces a uniform superconductor filler with a diameter of 3 to 5 microns. It is used to obtain ment. However, these Nb3Sn filaments is not superconducting at temperatures above 20"K.

Fine filaments (monofilaments) of metal precursors to high Tc superconducting oxides To date, high T c It has not been used as a means to obtain aligned particles of superconducting oxide.

Purpose of invention Accordingly, some objects of the present invention are that the preferred direction of superconductivity of the crystal is determined by the action of overcurrent. The superconducting crystal is crystallographically oriented in the same direction as required for Provides high-temperature superconducting structures that are resistant to cracking and have excellent superconducting properties when What to do: superconductivity such that the misorientation angle between superconducting oxide particles is minimal providing a core with a thickness of less than 20 microns, preferably as thin as a few microns; providing high temperature superconducting structures in one or more dimensions of the structure; Contains oxide particles with a long dimension (larger than 1/10) to provide high-temperature oxide superconducting structures that superconductors, such as sheets, tapes, and sheets; This includes providing a manufacturing process that is reliable and reproducible.

Summary of the invention The method of the present invention includes a step of blending a metal element that is oxidized to form a metal oxide; The process of putting the blended metal elements into a metal container and transforming the container and contents to create a precursor becomes very thin in at least one dimension perpendicular to its length , including the steps of decreasing its diameter and increasing its length. desired size and When the shape is obtained, the metallic elements of the superconducting oxide are oxidized to form the superconductor The deformed container is heat treated to This heat treatment is applied to thin superconductor dimensions. superstructure with at least one particle dimension larger than 1/10 of the Conducting to form conductive oxide particles. This composite has excellent mechanical properties and It has both superconductivity and superconductivity.

During heat treatment, the size of the growing oxide particles decreases to the thin dimension of the superconductor (? ! (also in the case of numbers) is compressed in the direction parallel to (?j [also in the case of numbers). The particles are Directions (or directions) that are not parallel to the non-thin dimension(s) of the superconductor In some cases, large growth is prevented. Additionally, anisotropy in growth rate for the crystallographic C-axis parallel to the non-compression direction(s). The grains were oriented in the crystallographic a-b plane parallel to the non-squeezing direction(s). Relatively small compared to fast growing neighboring particles. Between growth rate anisotropy and superconductivity The relationship is that the rapid growth plane of the grain (crystalline a-b plane) is coplanar with the preferred superconducting plane. It's a two-dimensional relationship. According to normal particle growth, the desired Large particles that are poorly oriented consume smaller particles that are not oriented as desired. There is a tendency to thus forming a superconducting oxide body with the desired superconductivity. In order to Both take advantage of the superconductivity of high Tc oxides and the natural anisotropy of grain growth.

The interface between the superconducting oxide and the non-superconducting metal container also contains superconducting oxide particles during heat treatment. plays a role in the alignment mechanism. Superconducting oxide-metal container interface The associated free energy varies with the crystallographic orientation of the superconducting oxide phase. If so, nucleation of the superconducting oxide phase at the oxide-metal container interface is preferred. A superconductor with a crystallographic orientation (e.g., C-axis perpendicular to the oxide-metal container interface) Produces conductive oxide particles. The mechanism of favorable superconducting oxide orientation near the interface is in each of the compressed volumes of the conductor or the interface between the superconducting oxide and the metal container. Or even if it comes from a combination, the oxide precursor perpendicular to the oxide precursor-metal interface The reduction in at least one dimension of the body layer reduces the superconductivity exposed at the interface. increases the fraction of oxidized oxide particles, which in turn increases the fraction of superconducting oxide particles with favorable crystallographic orientation. The fraction of conductive oxide particles can be increased.

A first preferred embodiment of the present invention comprises a core and a compressive material substantially surrounding the superconducting core. average of significant first fraction of superconducting oxide particles in non-superconducting boundary elements a coat having at least one thin first dimension that is less than or equal to 10 times the length; It is an elongated superconductor containing a core of superconducting oxide particles.

A second preferred embodiment of the invention provides that each compressive non-superconducting boundary element a plurality of superconducting cores substantially surrounded by a compressive non-conductive core; of the average length of the significant first fraction of superconducting oxide particles in the superconducting boundary element. The core has at least one thin first dimension that is 10 times or less at least one core, each comprising a plurality of cores of high temperature superconducting oxide particles, at least one high temperature superconductor, each comprising an innermost superconducting assembly It is an elongated superconductor that contains atomic assemblies.

A third preferred embodiment of the invention includes a metal precursor and a metal precursor core substantially surrounding the metal precursor core. a significant first fraction formed during heat treatment with oppressive non-superconducting boundary elements. A thin first layer, which is less than 10 times the average length of the superconducting oxide particles, A core with a dimension, a substantial component to form a superconducting oxide an elongated superconducting oxide containing a core of metallic elements of the superconducting oxide in stoichiometric proportions A metal precursor for heat treatment to form a body.

A preferred example of the method of the invention comprises a substantial stoichiometric amount to form a superconducting oxide. The process of forming a metal precursor core of a metal element of a superconducting oxide in a theoretical manner and the metal tip forming an oppressive non-superconducting boundary element substantially surrounding the precursor core; a precursor core and a boundary element having at least one thin first dimension; deformation into an elongated shape and heat treatment of the deformed combined precursor core and boundary elements. 1/10 of said thin first dimension of the deformed metal precursor core. also has a significant first fraction of oxide superconducting particles in the precursor core with a large average length. 1 is a method for manufacturing an elongated superconductor.

A second preferred example of the method of the present invention includes the following steps () until a predetermined number of cores are manufactured. ) and (if): (i) Substantial stoichiometry to form superconducting oxide (n) forming a metal precursor core of a metal element in a superconducting oxide; and (n) a metal tip. forming a compressive non-superconducting boundary element substantially surrounding the precursor core. tying the predetermined number of containing cores to at least one innermost core assembly; and for each of the at least one innermost assembly. forming a compressive non-superconducting boundary element of a size that substantially surrounds the containing core. and at least one innermost assembly. superconducting, including the step of deforming so that it becomes thinner in the first dimension A method of manufacturing an elongated superconductor having at least one assembly of magnetic cores. Then, the following steps (D~(tv): (i) Predetermined (n ) an oppressive non-superconducting boundary element of a size that substantially surrounds the combined containing core. forming and (quickly) filling the combined deformed assembly into the surrounding boundary element. to form an intermediate assembly with a greater degree of nesting than the deformed assembly being filled. (tv) and an intermediate assembly with a nesting degree greater than Repeat the process of deforming the first dimension so that it becomes thinner. , heat treating the deformed assembly with a predetermined degree of nesting to reduce at least one of the deformed cores. superconductor having an average length that is greater than or equal to 1/10 of one thin first dimension a significant amount of superconducting oxide particles of at least one precursor core that are oxide particles; This is a method for producing the first fraction.

A third preferred embodiment of the method of the invention provides the following steps until a predetermined number of cores are manufactured. Processes (i) and (fi): (i) Substantive chemistry for forming superconducting oxides forming a metal precursor core of metal elements of the superconducting oxide in stoichiometric ratios ) forming an oppressive non-superconducting boundary element substantially surrounding the metal precursor core; and repeating the steps of for each of the at least one innermost assembly; an oppressive non-superconducting boundary element sized to substantially surround the bound containing core; forming each of the at least one innermost assembly. also includes the step of deforming so that it becomes thinner in one first dimension. , Superden - 1tt core's small tj <tochihi> a (a long and thin superconductor that irritates the body) Manufacture of one metal layer of the body: 7J〈7A-〉, predetermined non-swing 1. f is 1 ] - Culm (i) - (iy) (i) A predetermined number of predetermined nestins with a predetermined configuration Unit culm that connects the deformed assembly of degree 1:: (ij) connects the t-hull A′ core Substantially (-forming an IE-impressive non-superconducting boundary element of size surrounding) 7 culms and , (th) Fill the combined (t) variable piece 3 assembly into the boundary element for the periphery, and fill. form an intermediate assembly with a higher degree of nesting than the deformed assembly to which it is inserted. 7 culms and (■) at least one metal precursor core (also one thin first The significant first fraction formed during heat treatment of the metal precursor core The larger the nest, such that it is less than 10 times the average length of the superconducting oxide particles of This is a method of repeating the process of deforming the intermediate assembly at different degrees.

Brief description of the drawing Figure 1 is a schematic diagram of a typical unit cell of the superconducting oxide, YBa2Cu30□-0. shows that the longest dimension of this unit cell is parallel to the C axis.

Figure 2 is a schematic illustration of a growing superconducting oxide particle, with the particle oriented parallel to the a-b plane. shows the fastest growth in

Figure 3 shows a growing superconducting oxide that is constrained to not grow too long in one direction. 2 is a two-dimensional schematic diagram of an object particle.

FIG. 41 is a schematic diagram showing the layered structure of a superconducting and non-superconducting noble metal composite.

FIG. 5 is a schematic diagram showing a container of inert material containing superconducting material.

FIG. 6 shows the structure shown in FIG. 5 modified to reduce their diameter and increase their length. 1 is a schematic diagram showing a container surrounding some of such containers; FIG.

FIG. 7 shows the structure shown in FIG. 6 modified to reduce their diameter and increase their length. 1 is a schematic diagram showing a container surrounding some of such containers; FIG.

Figure 8 shows the present invention applied to a single superconductor including a YBa2Cu307-superconductor. 2 is a flowchart schematically illustrating a method.

Figure 9 shows the cross-section of a large-area grain boundary in a superconductor containing C-axis aligned grains. 2 is a two-dimensional schematic diagram showing high current transport paths around grain boundaries; FIG.

Figure 10 shows the method of the present invention applied to multiple nested superconductors. 1 is a flowchart schematically illustrating the method;

Description of preferred embodiments of the present invention The present invention will be understood by reference to the following detailed description, discussion, and drawings. .

Figure 4 shows pure metal 1o separated by a thin layer of pure superconducting oxide 12. Pigeon's microlaminate 8 is a laminate with a high degree of ) Basics for obtaining crack-resistant superconductors with conductive oxide particle alignment 5, the maximum overcurrent 7'Wf is in the X or Y direction and generally in the x-y plane. A superconductor is used to allow the flow inside. It is not necessary for the overcurrent to flow in seven directions.

It will be appreciated that a crack such as 14 will interrupt the current in the X direction. . It will be appreciated that a crack such as 16 will interrupt the current in the X direction. For example, crack propagation as shown in 14 or 16 may occur in relatively ductile, crack-resistant pure It must pass through the metal layer 10, so it cannot pass through the metal-superconducting oxide. It is particularly difficult to initiate cracks in a single layer of superconductor when cracking other superconductor layers. It seems that it does not spread. For example, crack propagation like 18 is caused by the X-y It can still occur along directions lying in-plane. However, 18 types Some cracks will not completely block the current flow through the entire micro-laminate 8. follow Therefore, the conductivity of the micro-laminate 8 is more dependent on the applied stress than for pure oxides. may have low susceptibility to

Laminated superconducting oxide-metal composites are made by bonding superconducting particles in the laminate. The high degree of strength provides electrical property advantages over non-laminated composites.

The minimum concentration of superconducting particles in the complex required to maintain a continuous superconducting path is “ known as the ``percolation limit.'' In micro-laminates8, superconducting oxides are concentrated in the a-thickness zone. Therefore, oxide particles come into contact with nearby oxide particles. The possibility of forming dots is due to the random distribution of oxide particles in the noble metal matrix. larger than when In other words, the superconducting oxide in the micro-laminate 8 The local concentration of particles is higher than that of a more random microstructure, so the large size of the metal Percolation limits can be exceeded even in laminates with high volume fractions Micro-laminate 8 is a random combination of metal and oxide. A relatively large volume fraction of the metal compared to the composite with a bond loses its superconductivity. It can be included without.

A preferred embodiment of the invention is shown in FIG. In this case, the laminate is Takes the shape of a throat container. The outer container 60 is made of silver or other inert, deformable metal. Manufactured from Inert means a metal that does not degrade the superconductor. inert gold Although the genus is considered to be the same as the precious metals mentioned above, this may not necessarily be the case. Ru. Precious metals include the following metals: Ag5Au, Pd, Rh, Os, Ru, Ir, Hg and and Cu. Noble metals are complex compounds of metals and oxides. It can also be a combination. A plurality of intermediate container assemblies 58, in this case seven a-58g is nested within the outer container 60. Outer container 60 and intermediate container assembly Representing that each intermediate container assembly is connected to another intermediate container assembly and/or outer container 6. 0, the intermediate container assemblies are substantially displaced radially or circumferentially with respect to each other. contact so that they cannot move and the container assembly is not substantially deformed. size and shape. For example, the intermediate container assembly has a hexagonal cross-section It can have a shape like this.

FIG. 6 schematically depicts a typical intermediate container assembly 58, such as 58a. middle Container 70 is manufactured from an inert, deformable metal. multiple, in this case seven Intermediate container assemblies 68a-68g are nested within outer container 70. Internal content Container assemblies 68a-68g are connected to each intermediate container assembly with respect to intermediate container 70. The inner container assembly is connected to the inner container assembly of the pond and/or the intermediate container 70. abutted so that they cannot substantially move radially or circumferentially relative to each other; The container is of such size and shape that the container does not substantially deform when touched.

FIG. 5 schematically depicts a typical inner container assembly 68, such as 68a. internal The container 8() is manufactured from an inert deformable metal. Superconductor inside the inner container 80 oxide 82 is filled. (Aokinmetsuso 841 is also shown, but this is unnecessary. Therefore, the superconducting oxide phase 82 can occupy the entire space. ) Therefore, returning to Figure 7 Then, the inert structure is completely filled in the surrounding inert container, and the inert structure is Therefore, a plurality (in this case 49 (7x7)) essentially separated from each other. Contains parallel superconductors. In this way, a nestenodraminate is formed.

This body preferably extends along its long dimension/mino as indicated by arrow E. Used to conduct current.

The embodiment shown in FIG. 7 consists of an outer container 60, an intermediate container 58 and an inner container 68. However, the present invention also allows the existence of multiple levels or multiple levels with large intermediate nesting. will be understood by those skilled in the art to be within the scope of. In other words, the external content a container surrounding a plurality of first intermediate containers, each first intermediate container surrounding a plurality of second intermediate containers; Each second intermediate container includes a plurality of third intermediate containers, etc., and there can be an innermost The intermediate container of the section surrounds the plurality of inner containers. The degree of nesting determines the desired performance characteristics, e.g. Overcurrent capacity, resistance; normal current capacity: physical dimensions, etc., as well as e.g. ductility , necking, etc., depending on the deformability of the container.

Moreover, a set of ponds with a constant degree of nesting is different from a set of ponds with the same nominal degree. It is desirable that it be filled with For example, assembly 58a is nested three times. Formed from an assembly, 58b formed from a 4 degree nested assembly Is possible.

Furthermore, the embodiment shown in FIG. , all of which have a circular cross section, but the cross section of these asteroid vessels It will be appreciated by those skilled in the art that it is within the scope of the invention that the shape may differ from circular. It will be understood. There are no limitations on the possible cross-sectional shapes of the asteroid container. They are circular, oval, hexagonal, triangular, rectangular, and square.

The unstained structure shown in Figure 7 has the same crack resistance as described above for the laminate shown in Figure 4. It will be understood by those skilled in the art that this provides a high degree of character. superconductor 68 In either case, cracks may occur along the entire length of the superconductor. , it is difficult for such cracks to propagate to other superconductors. do it like this In order for the crack to pass through the metal container 80 surrounding the superconductor, the crack passes through the metal container 80 surrounding the superconductor, e.g. 68b, the superconductor, etc. No. This is due to the strong, crack-resistant properties of the metal container distributed throughout the laminate. It's difficult because of When the precursor is oxidized, rather than the precious metal being oxidized to the ceramic; Further crack resistance can be achieved by adding to the precursor a precious metal garden that remains a sideshow. This blue-gold phase, which can be strengthened to The additive metal matrix interspersed with superconducting ceramics shown in -1 unit [Enhance pigeon crack propagation resistance to J-1.

A cap that fills the inner container? , 4 days off (r': r + f1. If you do f), there will be a penalty Also) is the seed/r　fi,'j5 method Cp construction 6°・reru-1''21 沫understando1ishoulder- For example, 1, by oxidizing the precursor to the formed metal', Once subjected to appropriate heat treatment, which J22, which manufactures superconductors, can produce, metal elements can be combined in the precursor to obtain the desired metal ratio in the single conductive oxide. 3. Solid-phase methods (e.g. mechanical anastomosis, conversion and 'or blending of metal elements) ), liquid phase methods (e.g. molten alloy ratio) or gas phase methods (e.g. plasma, evaporation, (Y-Brain Yon, etc.) to combine metal elements to form a homogeneous, all-area precursor. I can do two things. Metal precursors can be used in both the solid phase (e.g. deformation, cutting) and liquid phase. methods (e.g. molten alloy into mold, gearing, powder or tape) solid, electrolytic) or gas phase methods (e.g. evaporation or sputtering onto shaped substrates) It can be molded by

A combination of shaping methods may also be used. For example, Suno (・ The substrate coated with the metal precursor by interpolation is filled into an inert metal container. , can be deformed into a desired shape.

With reference to FIG. 8, which schematically illustrates the method of the invention in flowchart form, the method of the invention will be understood. The method begins at 98. 1 metal precursor element Combine with 00. The metal precursor can include a noble metal. metal precursor in container 102 is filled. The filled container is transformed into the desired shape 104. Possible transformation methods includes, but is not limited to, drawing, rolling, extrusion, forging, pressing, swaging, swaging, etc. Deformation can also be carried out at elevated temperatures.

In this way, the filled container can be transformed into rods, wires, tapes, sheets, etc. can do. Since both the precursor and the container are metal, we , the “in-tube oxide-powder” method can be deformed simultaneously without the inhomogeneity problems mentioned above. can be done. This deformation is generally elongated (at least one point perpendicular to the direction of elongation). The deformation is such that it results in a very thin precursor region in one dimension. is preferable. Once the desired shape force +fi is obtained, heat the deformed container and precursor. Processing converts the precursor into a superconductor. Long, narrow, as discussed below. (The inset shape promotes crystallographic alignment during heat treatment of the shaped superconductor.

For example, the metal Y,[one Cu precursor is mechanically alloyed, placed in a container, and deformed. ) - thin in the direction of elongation at least 1. It takes 7' to obtain a metal precursor. Next, the deformed container is exposed to oxygen^1 in 106. Atmosphere T'T' typically at 400-600°C; however, the metal is thoroughly oxidized. . It is also possible to heat-treat the container at a low temperature of about 200C. L7, the oxidation rate (9) is very slow at this temperature. O S+: , heated to 700-940°C to form tetragonal YBa2Cu30. -, form. , greater than 1/10 of the thin dimension of the non-oxidized filament To obtain a significant fraction of Y [3a 2C11307-8 proofreading with length The time at 700-940"C must be long enough.

In fact, the longer the relative length of the average particle, the better; however, Y B a 2　Cu　*0□-2 particles present! The fraction is the size of the dimension t / If the length is greater than 1.0, it is considered that the benefits of the present invention can be obtained. available. At 110, the container is heated to 350-600°C in an oxygen-enriched atmosphere. and annealed to form a superconducting orthorhombic crystal, '1'B a2CIJ307-. do. Typical thin dimensions of metal precursors suitable for many applications include: ix, It is 10-3 cm.

The fraction of such long particles indicates that the superconductivity along a path consisting only of such long particles is It is considered significant if it is greater than or equal to the Percole-Noyon limit of the lead.

(Randomly oriented spheres required for electric Percolation in 3-day formation) The volume fraction of shaped particles is called the Percolay Noyon limit and is estimated to be approximately 0.015 It will be done. H,5cher,R,Zalten,J,Chem,Phys,, 53 (1970), p. 3759).

In this case, a significant fraction of YBa2Cu307-8 particles is lXl0- It should have a length that is not less than ’cm. In a preferred embodiment, a significant volume The fraction is greater than or equal to 0.15, and in the most preferred embodiment, greater than or equal to 0.5. this The reasons why it is advantageous to have a significant fraction of relatively long particles such as do.

Transforming the metal precursor into long (and thin) filaments provides enhanced electrical properties. This enables the production of high Tc superconducting oxides with high quality. A long, thin piece of metal precursor The growth of such oxide particles, resulting from the oxidation of a thin filament, results in high A preferred alignment of Tc superconducting oxide particles can be produced.

As mentioned above, the crystallography of the unit cell present in high Tc superconducting oxides Anisotropy in growth rate such that growth is fastest in the direction parallel to a-b exists. Therefore, the high Tc oxide particles have a plate-like or disk-like shape. In this case, thin grain dimensions result in a slow-growing crystalline structure. It is parallel to the scientific C direction. (See Figure 2). The invention also relates to superconductivity. The fact that anisotropy exists is utilized. Overcurrent causes crystal structure in high Tc oxide It flows most easily in a direction parallel to the a-b plane. As explained below, Besides giving rise to a significant fraction of particles longer than 1710 in the thin dimension of the wire In this invention, the direction of elongation (actively located in the preferred a-5 plane of maximum superconductivity) A superconducting acid with a long dimension in the direction of the required overcurrent) resulting in a significant fraction of compound particles. The direction of the required overcurrent is parallel to the direction of elongation. It will be appreciated that superconductors may be used in such devices.

The driving force for grain growth is the reduction in interfacial free energy associated with curved grain boundaries. ■] 111ert proposed the following general formula for normal particle growth.

dR, /d t=a:%1:S: [(1/R,,)-(1/R8)] (1) where R1 is the radius of particle I at time t, Ro, is the critical radius at time t is the particle radius (related to the average grain (9)), M is the grain boundary mobility, and Sl is the grain boundary mobility. The energy is kyoma, and al is the dimensional Hue constant (related to particle shape) . M. Hillerl, Acta N1et, vol. 13, 1965. p. 227.

From Equation 1, particles with an average radius k greater than the critical half i\ will grow, but the critical radius Particles smaller than , shrink. In other words, during normal particle growth, large particles Processes that consume smaller particles increase the average particle size.

The change in grain growth rate due to crystallographic orientation is similar to the change in grain growth rate due to crystallographic orientation. or by changes in N1 (or both). As discussed below, such anisotropy Geometrical L) A desirable crystallographic alignment can be obtained.

Figure 2 shows a two-dimensional schematic of a metal precursor tape containing i>:'i'll/-. this tape It has a thin 1 day long 41' length and a long 2 day long length. long dimension One of the options is the operationally necessary direction of bulk superconductivity, which is indicated by direction E. be suggested.

During heat treatment, superconducting oxide particles nucleate at various locations within the elongated body. nuclear The formation results in various grain orientations as shown in FIG. For clarity, the grains shown in Figure 3 The crystal structure of the oxide parallel to the disk plane is a-b. Assume that it has a surface. A cross section of the disc-shaped particle is shown in FIG. In this example, the particle grows much more rapidly in the direction parallel to the a-5 plane than in the grain direction. It is assumed that That is, disk-shaped particles grow rapidly in the radial direction, Slow thickening is assumed. At an angle q (1-6) with respect to the container wall 460 The oriented particles 402 continue until they obstruct the container wall (as expressed by Equation 1) ) can continue to grow. Therefore, after a sufficient period of particle growth, particles 40 4 has a larger radius than the particle 402 (can be formed; the radius of the particle 402 is critical). If it is smaller than the radius, the particles 402 will shrink and eventually disappear. Therefore, capacity The pressure exerted by the vessel wall induces knots in the distribution of particle orientation, so The volume fraction of oriented particles increases with increasing annealing time. paraphrase , the C-axis orientation of the significant second fraction of grains is parallel to the thin dimension of the tape. Align to. The direction required for superconductivity is the preferred superconducting plane of the particle. Such particle alignment is highly desirable since it lies parallel to the a-5 plane. Yes.

In the ideal case, the fraction of particles thus aligned would be contains most of the fraction and is larger than 1/10 of the thin dimension of the filament equal to or slightly less than a significant first fraction of the particles having a length A preferred embodiment of the superconductor of the invention consists only of long, aligned particles. Aligned grains that are also at the superconducting Percollenoyon limit 79 have a significant second fraction of children. In a preferred embodiment, such a significant fraction is 0.015, and in the most preferred embodiment the significant fraction is greater than 0.5.

However, even with perfect C-axis alignment, C-axis tilt and twisted grain boundaries remain.

Critical electric potential resulting from random high-angle C-axis tilt and electrical transport across twisted grain boundaries The flow density is relatively low. However, if such grain boundaries have large areas, this The critical current transported between particles such as , tends to be relatively high. The critical current is as below It is related to critical current density using a relatively simple expression.

1, = JC-A (2) In the formula, J and IC are the critical current density and critical current, respectively, and A is the overcurrent flowing. is the cross-sectional area. Therefore, even if the JC between misoriented particles is relatively small, If the common area shared by particles is large, ■, will still be large. Can be done. As schematically shown in FIG. It traverses the grain boundary 406 of the region and passes around the grain boundary 408 of the small region. (A, P.

Malozemoff, High Temperature 5upercon Ducting Compounds I1. S., H., Whang, A.D. asgupta, R, Laibowi tz41i collection, TMS, Pennorveni AL, Varendaal, 1990.3, p. 3, see hereby reference for reference. and). Therefore, superconductors containing a significant second fraction of particles with C-axis alignment Despite the presence of some C@ tilt and twisted grain boundaries, the tape has a large overcurrent. Can be transported. - one or more anisotropic grain growths of oxides as described above; By suppressing in the dimension of You can get a lot of money.

High Tc superconducting oxides (e.g. RE-Ba-Cu-0 series, (Pb, Bi)-8 r-Ca-Cu-0 system, TI-Ba-Ca-Cu-0 system (RE is a rare earth element Copper(■1) acid salt superconductors) exhibit grain growth anisotropy, which means is an aspected grain with a thin dimension parallel to the crystallographic C direction. The geometrically restrained grain growth of these oxides results in the formation of C-axis grain a Promote line mates. Furthermore, superconducting compounds exhibiting anisotropy of grain growth ( oxides or non-oxides), the grain growth is controlled by the geometry in one or more dimensions. It is thought that alignment can be achieved by chemically suppressing this. The above is The C axes of all particles are parallel to each other and to the thin dimension of the elongated superconductor. Consider the buried case where the C axes of all particles are substantially aligned, at small angles to each other and to the direction of the thin dimensions of the elongated superconductor. Superconductivity can be enhanced even in less logical situations such as Wear.

See Dimos et al. in kUe. The preferred angle of malalignment is 30 The most preferred angle of misalignment is less than 10°.

Reducing the above to τ is an important point in obtaining a high degree of C-axis particle alignment. is the ratio of the particle length to the size of the geometrically constrained thin dimension. Ru. After annealing, at least a significant fraction of the superconducting oxide particles are deformed Preferably it is at least 1/1o thicker than the thinner dimension of the container.

Therefore, in some cases at least a significant fraction of the superconducting oxide particles are also align such that the C axis of is parallel to the thin dimension of the deformed container. .

The phrase “significant fraction” is used to express means the critical volume fraction of particles required to cause an overcurrent to flow.

The above discussion with respect to Figure 3.8.9 shows that a single It was concentrated in an elongated superconductor. However, multiple such superconductors and thereby form a preferred superconductor of the crystallographically aligned superconductor described above. In addition to conductivity, obtaining favorable crack resistance of the laminate is also a significant aspect of the present invention. It is.

Some of these compacts can be refilled into other inert metal containers and reshaped to create a matrix. A multifilamentary molded body can be formed. silver, gold or silver-gold alloy Ratio for Y-Ba-Cu-O and Pb-B1-8r-Ca-Cu-0 superconductors This is an example of a relatively inert substance.

Rather than by directly heat treating the container after step 104 in FIG. , Figure 10. As shown in step 304, several such containers are manufactured and these It is advantageous to fill the container into a larger inert container in step 306. be. This results in a body such as 58a shown in FIG. This nested body By any of the above methods, it is elongated and perpendicular to the direction of elongation, the individual is deformed at 308 such that the dimensions of the inner container of are reduced. this At some point, the deformed nestesoto body can be heat treated as described above.

However, before heat treatment, additional degrees of nesting and deformation are performed, as shown in step 310. It is advantageous to give Some modified versions, such as 58a in FIG. 62 shown in FIG. form a body like Transforms the resulting body itself, and the body nested inside it further stretched, thereby increasing one or more of the dimensions perpendicular to the stretch. Further decrease. The deformed body can be heat treated at this point or even larger Can be combined into other bodies of stinging degree. easily understood by those skilled in the art The nesting changes depend on the ductility, elasticity, and other parameters of the precursor and inert container. Depending on the data, it can be increased to increasingly large degrees. Finally, the desired When the final size and shape of and then heat-treated.

The invention may be further illustrated with reference to the following examples.

Example 1 metal)′, Ba, Cu1. Mechanically alloyed 8g in a high energy ball mill become The ratio of metal species is Y:Ba:Cu:Ag=1:2:3:X (X>O) be.

All metal powder is filled into a steel pipe. This tube is welded shut. Next, heat the tube to 300°C. isostatically extruded into a hexagonal cross-section wire. Such a deformed tube Some of them are refilled into other steel pipes. This multifilament tube is then heated to 300°C. isostatically extruded. Recycling some of these multifilament tubes and other steel tubes and isostatically extruded at 300'C. This fullness Filling-deformation-refilling-deformation process is carried out at least once in each filament core. until the thickness of the two dimensions is 100 microns thick, preferably 10 microns thick. Repeat until the thickness is less than a kilometer thick. Next, the multifilament tube is The metal is completely oxidized by heating to 500° C. in an atmosphere. This tube is next 92 Heating to 0°C for 400 hours forms tetragonal YBa2Cu30□-0. 1 A significant fraction of 'i'Ba2cu30□-8 particles with lengths less than 0 microns F The time at 920° C. is selected to obtain the desired temperature. This tube is then placed in an oxygen-containing atmosphere. annealed at 500°C to form superconducting orthorhombic YBa2CLl Form 30t-x.

Example 2 Metal Y and Ba are mechanically alloyed in a high energy ball mill. Y and B Powder a is placed in a steel tube, which is then placed in the steel tube. Steel pipe thickness and Y and Ba powder The final additive layer is defined so that the Y:Ba:Cu ratio in the steel pipe is 1.24.

This steel pipe is welded closed. Next, the tube was hydrostatically heated to a hexagonal cross-section at 300°C. extruded into ears. Refilling some of these deformed pipes into other steel pipes Ru. This multifilament tube is then hydrostatically extruded at 300°C. Ru. Some of these multifilament tubes are refilled into other steel tubes and deformed. do. This filling-deformation-refilling-deformation process is repeated for each filament core. Preferably until at least one dimension is less than 100 microns thick. Repeat until the thickness is less than 10 microns. Next, multifilament Heat the tube to 400-600°C in an oxygen-containing atmosphere to completely oxidize the metal. Ru. This tube was then heated to 700-835°C for 20-400 hours to produce YBa, Cu, Form 30t-x. The time at 700-835℃ is 10 microns or more. Y B a 2 Cu 307 with length - to obtain a significant fraction of particles should be of sufficient length.

Example 3 An alloy of composition YBa2Cu3 was mechanically alloyed in a ball mill and then in Ag powder. Manufactured by blending. The molar ratio of metal species in the blend is Y:Ba Cu:Ag-1:2:3.X<X>O>. All metal powder in steel pipe Fill it. This tube is welded shut. The tube was then hydrostatically heated at 300°C. Extruded into square cross-section wire. Some of these deformed pipes are mixed into other steel pipes. Refill. This multifilament tube was then hydrostatically pressed at 300°C. Extrude and mold. Refill some of these multifilament tubes into other steel tubes again and hot extrusion molding. This filling-deformation-refilling-deformation process is repeated for each frame. At least one dimension of the filament core is less than 100 microns thick Repeat as described above until a thickness of, preferably less than 10 microns is obtained. return. The multifilament tube is then heated to 400-600℃ in an oxygen-containing atmosphere. Heat to completely oxidize the metal. This tube is then heated to 700-940℃ for 20~ Heating is performed for 400 hours to form a square product system YBa2Cu3o7-1. 7 The time at 00 to 940°C is YBa with a length of 10 microns or more. 2Cu 307 - Should be of sufficient length to obtain a significant fraction of particles . The tube is then annealed at 350-600°C in an oxygen-containing atmosphere to Conductive orthorhombic YBa and Cu307-0 are formed.

Example 4 Composition YbBa2Cu, produced by melt spinning (rapid solidification of molten alloy) do. Y　b　B　a　, Cu　,、The long dimension of the ribbon is the pipe parallel to the long dimension of (=fill into the coarse tube. This filling is Performed by stacking alternating layers of Ba2Cu3 ribbon and silver ribbon . Weld the tube closed.

The tube is then gauge rolled into tape shape. Insert such deformed tape into other root canals. Refill. This multifilament tube is then hot rolled into a tape shape. this Some of their multifilament tapes were refilled into other root canals and hot rolled. Ru. This filling-deformation-refilling-deformation process is repeated in each filament core. (preferably until one dimension is less than 100 microns thick) Repeat until the thickness is less than 10 microns. This multifilament tape The sample was then heat treated in the same manner as the body of Example 3 to form superconducting orthorhombic YBa, Cu. 307-1 is formed.

衷應绚仝 A thick film consisting of layers of Y, Ba and Cu was deposited on a silver substrate by plasma spraying. Attach it on top. The ratio of metal species in the film is Y:Ba:Cu=1:2:3 . The coated silver substrate is filled into the root canal. This filling is done with Y-Ba-Cu film. Carry out so as to form alternating layers with copper tubes. Weld the tube closed. then tape the tube Hot press into shape. Re-insert some of these pressed tapes into other root canals. Fill. This filling-deformation-refilling-deformation process is repeated for each fill in the tape. At least one dimension of the lament core is less than 100 microns thick Repeat until a thickness of less than 10 microns is achieved. This multi The filament tape was then heat treated in the same manner as the body of Example 3 to form a superconducting orthorhombic YBa 2CLl 307-2 is formed.

Harumon once Mechanical alloy of 5r2Cal and/or elemental Sr+Ca with seeds Bi, CuSAg and/or blended with elemental B1 and Cu. Bu The ratio of metal species in the blend is 2:12. Fill the root canal with all-metal powder.

This tube is welded shut. The tube is then hot pressed into a tape shape. This kind of strange Refill some of the shaped tubes into the root canal of the pond and hot press the tubes into a tape. .

This filling-deformation-refilling-deformation process is carried out in a small amount of each filament core. preferably until one dimension is less than 100 microns thick. Repeat until thickness is less than 10 microns. Next, the tape is placed in an oxygen-containing atmosphere. The metal is completely oxidized by heating to 400-600°C. this tape next Superconducting oxide Bi25rzcalCu@Ox is heated to 700-940°C. Form. The time at 700-940°C has a length of 1 (] micron or more To obtain a significant fraction of Bi2Sr2Ca (CLJ20r particles) It should be of sufficient length.

is the 1st edition- A mechanical alloy of B1□5r2Ca+Cu2 is blended with elemental Ag. metal species The ratio is Bi:Sr:Ca:Cu:Ag=2:2:1:2+X (0<X<50). Ru.

Fill the root canal with all-metal powder. This tube is welded shut. Next, heat the tube to 300℃ It is then hydrostatically extruded into a tape shape. Some of these deformed tubes Refill into the root canal of the pond, which is then hydrostatically extruded into a tape shape. this Filling-deformation-refilling-deformation... process at least Preferably 10 until one dimension is less than 100 microns thick. Repeat until thickness is less than a micron. Next, apply the tape to the body in the same way as in Example 6. A superconducting oxide, Cu, O, is formed by heat treatment.

! chapter once Mechanically alloyed 5r-Ca and/or a simple blend of elements Sr+Ca, mechanically alloyed Alloy Cu-Ag and/or simple blend of elements Cu+Ag and mechanical alloy B1 - Mixing Pb and/or a simple blend of elements Bi and Pb. in blending The ratio of metal species is Bi:Pb:Sr:Ca:Cu:Ag=1.5:0.5:2:2. 3.X (X=0 to 50). Fill the root canal with all-metal powder. Melt this tube Close the connection. Next, the tube is track pressed into a tape shape. This deformation is one phase of the precursor It is carried out at a temperature exceeding the above melting point (125°C to 328°C). like this Some of the deformed canals are refilled into other root canals, which are then injected with one or more phases of the precursor. Hot pressing at a temperature above the melting point. This filling-transformation-refilling-transformation... ...process so that at least one dimension of each filament core is 100 to a thickness of less than a micron, preferably to a thickness of less than 10 microns ,repeat. The tape is heated to 400-6000C in an oxygen-containing atmosphere to completely oxidize. This wire is then heated to 700-940°C to make it superconducting. oxide (Bi, Pb)2CazCu30. form.

The body was heat-treated in the same manner as in Example 6 to form superconducting oxides Bi25r2Ca, Cu2O. , form. The time at 700-940°C has a length of 10 microns or more. B i, 5r2calcu2 (long enough to obtain a significant fraction of L particles) It should be. Final oxygenation at 350-600°C for this tape. Annealing is carried out to maximize the critical temperature, below which this superconductivity body resistance metal copper rod alloyed or blended with yttrium metal and barium metal The composite is manufactured by inserting the composite into a tube consisting of a. Y Ba ratio of tube is 1:2. The diameter of the copper rod and the thickness of the Y-Ba tube are such that the total composite is Y:Ba :Cu ratio of 123. The inner rod structure is then replaced by a silver flute (can). ) and weld. This tube is then extruded into wire shape. like two Some of the deformed composite canals are refilled into other root canals. This multifilament The tube is then extruded. Insert some of these multifilament tubes into other root canals. Refill and extrude. This filling-deformation-refilling-core deformation process at least one dimension of the valley filament core is less than 100 microns Repeat until a thickness of less than 10 microns is achieved, preferably less than 10 microns.

This multifilament tube was then heat treated in the same manner as the body of Example 3 to form a superconducting diagonal. Square system Y B a 2 CLJ 307- + shape fft6゜Example 10 The copper rod is made of a blend of Ba and Y powder, or mechanically alloyed Ba-Y powder, or It is filled into the root canal along with Ba and Y rapidly solidifying powders. Y:Ba ratio in the tube is 12, the diameter of the copper lot and the amount of Y-Ba powder added to the copper tube are the total composite What is the YBaCuO ratio, 123? Copper tube containing powder and rod Then weld it closed. This tube is then extruded into wire shape. This kind of strange Refill some of the shaped tubes into the root canal of the pond. ・・・・・・The process is carried out so that at least one dimension of each filament core is 1. to a thickness of less than 00 microns, preferably less than 10 microns. Repeat until. This multifilament tube was then heat treated in the same manner as the body of Example 3. Thus, superconducting orthorhombic YBazCu30y-+ is formed.

Example 11 The in-tube rod method of Examples 9 and 10 can be applied to the B1-5r-Ca-Cu system. can. Ca and Sr are used instead of Y and Ba, and the Ca:Sr ratio is 2:1.

A B1-Cu rod is used instead of a copper rod, and the elemental ratio of B1/Cu is 2.2. Ru. B1-Cu rod and Ca-8r tube or Ca-8r powder with total metal precursor core is placed in a silver tube such that the Bi:Sr:Ca/Cu ratio is 2:2/12.

The deformation cycles described in Examples 9 and 10 remain the same. Example of post-deformation heat treatment This is the same as the heat treatment described in 6.

Example 12 Applying the rod-in-tube method of Example 9 and IO to the Pb-B1-8r-Ca-Cu system be able to. Ca and Sr were used instead of Y and Ba, and the Ca:Sr ratio was 2:2. be. Using Pb-B1-Cu rod instead of copper rod, Bi:Pb:Cu The element ratio is 2-X.X3, where X is in the range of O to 0.5. Pb-B1- Cu rod and Ca-3r tube or Ca-3r powder, the total metal precursor core is Pb/B i:Sr:Ca:Cu ratio, X:2-X:2:2:3 Put it in a silver tube like this. The deformation cycles described in Examples 9 and 10 remain the same. Ru. The post-deformation heat treatment is the same as the heat treatment described in Example 8.

As mentioned above in connection with the Yurek patent, superconductor precursors combine with precious metals. In some cases, it is also possible to provide superconductors with very thin conductors.

The noble metal can be combined in intimate admixture with the precursor. Heat treatment results As such, the precious metal is essentially pure gold in fine powder form, intimately mixed with superconducting oxides. Precipitates as a genus phase.

The presence of noble metals intimately mixed with the oxide superconductor phase generally affects the mechanical properties of the superconductor. to make oxide-metal composites more resistant to cracking and other damage. Ru. The present invention minimizes the need for some improvement in mechanical properties because the layer For example, a metal sandwiched between layers of superconductor that are shaped or concentrically or otherwise deformed This is because it provides several desirable mechanical properties, such as stiffness, strong shock resistance, etc.

However, superconducting oxides remain brittle and susceptible to destruction. superconducting oxide The presence of precious metals intimately mixed with reduces the propagation tendency of cracks. However, precious metals are expensive. A trade-off occurs because the oxide grains interfere with the oriented growth of the oxide particles. Emphasis on superconductivity an amount of precious metal that provides the necessary degree of improvement in mechanical properties without significant deterioration; Determining is a matter of routine experimentation for those skilled in the art.

Example 1 sword The methods of Examples 9 to 12 were carried out in the presence of Ag in the metal precursor rod or tube or powder. implement.

As mentioned above, a major advantage of the present invention is that the operationally determined direction of the bulk overcurrent having superconducting oxide particles oriented in a preferred crystallographic direction aligned with The goal is to provide a body that can help people. This advantageous particle alignment is achieved by wire, rod This is considered to be most noticeable for thin shapes such as tapes. sheet super In applications where a conductor is required, the crystallographically preferred plane of superconductivity is the sheet plane. Forms a sheet of superconducting oxide particles aligned in the same plane be able to. Therefore, superconductors are rolled, pressed, etc. into a flat sheet shape. It is also within the scope of the present invention to modify the shape.

The present invention is based on the applicant's co-pending patent application titled "A Process for Ma king Ceramic/Metal and Ceramic-Ceram ic Lam1nates by Oxidation of a MetaI "Precusor", by the name of Kenneth H. Sandhage, 19 Filed on April 3, 1991, U, S, S, N, 67, incorporated herein by reference. It can also be used in combination with the invention described in No. 9614. In summary, this The invention discloses that precious metals can be used under conditions of alternatingly high and low oxygen partial pressures and/or low and high temperatures. The present invention relates to oxidizing group-containing metal precursors. Such fluctuations (oscilla ting) The heat treatment is an alternating oxidation process containing relatively high and low concentrations of superconducting oxide particles. Produces bands. This variable oxidation is suitable for noble metal-containing metal precursors of the type mentioned above, including finer than that already formed by the successive application of deformation and refilling. Partitions of superconducting oxides and metals can be formed. Variable oxidation method is mechanical It can be applied to the precursor at or before the end of the transformation. 2 methods By combining very thin filaments of superconducting material with non-superconducting layers can be suppressed to grow between. Ultra-thin layers are preferred as mentioned above. This allows the growth of superconducting oxide particles with fine crystallographic orientation. Therefore, the original The Bspect of the Ming device originates from the metal container wall and/or fluctuating oxidation. superconducting by regions containing low concentrations of superconducting oxides (high concentrations of non-superconductors). A superconductor with an elongated, thin superconducting band delimited by a conducting band.

Instead of step 106 as shown in FIG. 8, the superconductor may be subjected to a variable oxidation heat treatment. is one embodiment of the method of the present invention. This variable oxidation heat treatment is as shown in Figure 5. It can be added to either a single superconductor or a nested body as shown in Figure 7. It will be understood that

The above statements should be construed as illustrative and not limiting in any way. There isn't. Having thus described the invention, it resides within the scope of the following claims.

FIG. 2 Joshu (changed content) FIG. 10 Written amendment (procedural amendment) June 1994/6th W ringing

Claims (20)

[Claims] 1. The following elements: a. a core of a superconducting oxide particle, said core comprising a significant first fraction of said core; at least one thin first layer that is less than or equal to 10 times the average length of the superconducting oxide particles; having dimensions; and b. elongated, including an oppressive non-superconducting boundary element substantially surrounding a superconducting core superconductor. 2. Each of the following elements: a. a plurality of cores of high temperature superconducting oxide particles, said cores having a significant first at least one whose fraction is less than or equal to 10 times the average length of said superconducting oxide particles and each core is bounded by a compressive non-superconducting boundary element. is substantially surrounded by: and b. comprising a constrictive non-superconducting boundary element substantially surrounding a plurality of superconducting cores; at least one each having at least one innermost superconducting assembly An elongated superconductor containing two high-temperature superconducting assemblies. 3. a metal precursor for heat treatment to form an elongated superconducting oxide object, , the following elements: a. the superconductivity in a substantially stoichiometric ratio to form the superconducting oxide; a core of a metal element of the oxide, said core being formed during heat treatment of said metal precursor; at least 10 times the average length of a significant first fraction of superconducting oxide particles; also has one thin first dimension; and b. substantially metal precursor core A metal precursor containing a surrounding, oppressive non-superconducting boundary element. 4. A method for manufacturing an elongated superconductor, comprising the following steps: a. The superconducting oxide a metal tip of said superconducting oxide metal element in a substantially stoichiometric ratio to form forming a precursor core; b. An oppressive non-superconductor substantially surrounding the metal precursor core. forming a conductive boundary element; c. the combined precursor core and boundary element in at least one thin first dimension; deforming into an elongated shape having a yong; d. the deformed combination precursor core; the thin first dimension of the deformed metal precursor core by heat treating the boundary element; oxide superconductivity of said precursor core having an average length greater than 1/10 of the producing a significant first fraction of particles; manufacturing methods including. 5. Fabrication of an elongated superconducting medium having at least one assembly of superconducting cores A method, comprising the following steps: a. Steps (i) and (ii) below until a predetermined number of cores are manufactured: (i) Superconductivity Superconducting oxide metallic element gold in substantial stoichiometric ratio to form oxide (ii) forming an oppressive metal precursor core substantially surrounding the metal precursor core; forming a non-superconducting boundary element; and A process of repeating; b. coupling a predetermined number of containing cores to at least one innermost core assembly; With Cheng; c. Runs a combined containing core for each of at least one innermost assembly. forming an oppressive non-superconducting boundary element of qualitatively surrounding size; d. Small each of the at least one innermost assembly in at least one first dimension; deforming the material so that it becomes thinner in the container; e. When the specified degree of nesting is obtained. Steps (i) to (iv) below until coupling the degree deformation assembly; (ii) an oppressive non-superconducting boundary that is sized to substantially surround the bound containing core; forming the element; (iii) filling the combined deformed assembly into a perimeter boundary element to forming an intermediate assembly with a greater degree of nesting than the deformed assembly; ; (iv) placing the intermediate assembly of greater nesting degree in the at least one first device; a step of repeating the step of deforming so as to become thinner in dimension; f. The deformed assembly with a predetermined degree of nesting is heat treated to form at least one of the deformed cores. A superconductor with an average length that is more than 1/10 of the thin first dimension a significant first fraction of the superconductivity of at least one precursor core that is a oxide particle; The process of manufacturing oxide particles and manufacturing methods including. 6. Elongated superconductor metal tip having at least one superconducting core assembly A method for producing a precursor, comprising the following steps: a. The following steps are performed until the specified number of cores are manufactured. Processes (i) and (ii): (i) substantial stoichiometry for forming superconducting oxides; forming a metal precursor core of a metal element of a superconducting oxide at a ratio of (ii) gold forming an oppressive non-superconducting boundary element substantially surrounding the precursor core; The process of repeating: b. coupling a predetermined number of containing cores to at least one innermost core assembly; With Cheng; c. Runs a combined containing core for each of at least one innermost assembly. forming an oppressive non-superconducting boundary element of qualitatively surrounding size; d. each of the at least one innermost assembly in at least one first dimension; deforming the material so that it becomes thinner in the section; e. A given degree of nesting is obtained. Steps (i) to (iv) below until combining the deformed assemblies of the same degree; (ii) an oppressive non-superconducting boundary that is sized to substantially surround the bound containing core; forming the element; (iii) filling the combined deformed assembly into a perimeter boundary element to forming an intermediate assembly with a greater degree of nesting than the deformed assembly; ; (iv) at least one thin first dimension of the at least one metal precursor core; John has a significant first fraction of superconducting acids formed during heat treatment of the metal precursor core. intermediate to a greater degree of nesting, such that it is less than or equal to 10 times the average length of the compound particles; a process of deforming the assembly; a process of repeating the process; method including. 7. the average length of the significant first fraction of the superconducting oxide particles is of the core; 2. The at least one thin first dimension is greater than 1/2. superconductor. 8. the average length of the significant first fraction of the superconducting oxide particles is of the core; 2. The supertransmission according to claim 1, which is larger than said at least one thin first dimension. conductor. 9. a c dimension in which the superconducting oxide particles are long; A unit with a and b dimensions that are both shorter than c dimension, which is longer. the oxide particles exhibit superconducting anisotropy and have two short dimensions. 2. The superconductor of claim 1, wherein the superconductivity of the a-b plane defined by John is highest. a conductor in a direction parallel to the thin first dimension of the superconductor; so that the perpendicular vector lies at an angle of less than 30° to the a-b plane. A superconductor further comprising a significant second fraction of particles aligned to . 10. The superconductor according to claim 9, wherein the significant second fraction is 0.15 or more. 11. the significant second fraction is comprised solely of superconducting oxide particles of the significant second fraction; The superconductor according to claim 1, which has a percolation limit of superconductivity along the path formed by the superconductor. conductor. 12. each assembly includes at least one intermediate assembly, each intermediate assembly 3. A superconductor as claimed in claim 2, wherein the li comprises a plurality of innermost superconducting assemblies. 13. The superconductor according to claim 1, wherein the superconducting oxide includes thallium. 14. A superconductor according to claim 1, wherein the superconducting oxide comprises bismuth. 15. The superconductor according to claim 1, wherein the superconducting oxide contains copper. 16. The superconducting oxide object of claim 1, wherein the core further comprises a noble metal. 17. at least one dimension of said core is smaller than 100 microns 5. The method of claim 4, wherein said metal precursor core is deformed so as to. 18. The superconducting oxide body of claim 1, wherein the non-superconducting boundary element comprises a metal. 19. a c dimension in which the superconducting oxide particles are long; , both have a and b dimensions that are shorter than the longer c dimension. comprising a unit cell, the oxide particles exhibit superconducting anisotropy, and two short dimensions 2. The superconductivity of claim 1, wherein the superconductivity of the a-b plane defined by the region is highest. a superconductor in a direction parallel to the thin first dimension of the superconductor; is located at an angle of less than 30° with respect to the a-b plane. A superconductor further comprising a significant second fraction of uniformly aligned particles. 20. perpendicular to a direction parallel to the thin first dimension of the superconductor; 26. The vector is located at each angle less than 10 degrees to the a-b plane. superconductor.