Abstract: A nitrogen oxide sensor and a method of manufacturing the sensor are disclosed. The sensor has a gas detecting portion including sensitive material having electric property thereof subject to change in association with presence of nitrogen oxide in gas and a pair of electrodes electrically connected with the gas detecting portion. The gas detecting portion includes, as a main component thereof, metal oxide compound represented by a general formula:Bi.sub.2 Sr.sub.2 (Ca.sub.1-x Y.sub.x)Cu.sub.2 O.sub.8+y(0.8.ltoreq.x.ltoreq.1; 0.ltoreq.y.ltoreq.1)and having the 2212 phase crystal structure and crystalline size greater than 100 .ANG..

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: Improved superconducting thin films are provided having very high T.sub.c (zero) and J.sub.c values, on the order of greater than or equal to 120K and 10.sup.5 A/cm.sup.2 or greater, respectively. The films of the invention are adapted for deposit and support on a compatible substrate, and include a superconductive material, most preferably Tl.sub.2 Ba.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10, with up to about 10% elemental gold admixed with the superconductive material. The preferred method for fabricating the thin film superconductors comprises first forming a non-superconducting precursor film on a compatible substrate which is placed in contact with an unsintered bulk body containing thallium; the substrate with precursor film are sintered with the bulk body to form the desired superconductor material.

Abstract: The process for producing high-T.sub.c superconductors containing thallium, calcium, barium and copper, possibly also lead and/or strontium, provides for a thallium-free precursor to be produced in a first reaction step and this to be then mechanically triturated, subsequently heated to temperatures in the range from 700.degree. to 950.degree. C. and heat treated for a period of at least 3 hours. The mixture is then cooled to ambient temperature and ground again. Finally, it is heat treated at temperatures of from 400.degree. to 500.degree. C. in a stream of pure oxygen. The thallium-free precursor is then triturated with Tl.sub.2 O.sub.3, if desired shaped into a shaped part and then oxidatively fired in a flowing gas atmosphere.

Abstract: The present invention provides a (Bi,Pb)SCCO-2223 oxide superconductor composite which exhibits improved critical current density and critical current density retention in the presence of magnetic fields. Retention of critical current density in 0.1 T fields (77 K, .perp. ab plane) of greater than 35% is disclosed. Significant improvements in oxide superconductor wire current carrying capacity in a magnetic field are obtained by subjecting the oxide superconductor composite to a post-processing heat treatment which reduces the amount of lead in the (Bi,Pb)SCCO-2223 phase and forms a lead-rich non-superconducting phase. The heat treatment is carried out under conditions which localize the lead-rich phase at high energy sites in the composite.

Abstract: The hole density of an oxide superconductor having holes as carriers is higher than the hole density to bring the highest value of the superconductivity critical temperature Tc thereof, and it can be made higher than the optimal density to bring the highest Tc value by treating the oxide superconductor with heat in an oxidizing gas atmosphere, or by replacing positive ions constituting the oxide superconductor except for copper with ions of a low valence number. Accordingly, it is possible to substantially reduce the rate of decrease of the critical current density owing to an applied magnetic field when the magnetic field is applied parallel to the crystal c axis, and to allow a current conductor produced by using the oxide superconductor to have high critical current density.

Abstract: A process for making a superconducting, Pb-doped, 2:2:2:3 BiSrCaCuO thin film includes heating deposited thin film material at between 1083K and 1103K for no more than 20 minutes in oxygen with a flow rate of 500 sccm, followed by quenching the material in air to room temperature, heating the material in air between 1103K and 1143K for no more than 40 minutes and finally quenching the material in air to room temperature.

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: Process for increasing the pinning force of superconducting Bi-Sr-Ca-Cu-O ceramic moldings, which comprises heating the pure-phase 2212 phase of a Bi-Sr-Ca-Cu-O ceramic molding under pure oxygen or an oxygen-containing gas for from 1 to 40 minutes to a temperature of from 825.degree. to 900.degree. C. and generating secondary-phase precipitates in the process.

Abstract: A process for controlling crystalline orientation of an oxide superconductive film includes a first-heat-treatment step, and a second-heat-treatment step. In the first-heat-treatment step, an oxide superconductive film is heated and held in non-oxidizing atmosphere. Accordingly, partial oxygen deficiency is caused in the oxide superconductive film. In the second-heat-treatment step, the oxide superconductive film is heated and held in oxygen-rich atmosphere. Consequently, oxygen is re-introduced into the oxide superconductive film. Thus, crystalline orientation of the oxide superconductive film is altered. The process enables to readily form not only an "a"-axis-oriented oxide superconductive film but also a "b"-axis-oriented oxide superconductive film.

Abstract: A description is given of superconducting substances having a content of Bi, Sr, Ca and Cu, and of processes for their preparation from the metal oxides within a range which is specified by the overall composition Bi.sub.a (Sr,Ca).sub.b -Cu.sub.6 O.sub.x, where a=3-24 and b=3.23-24, with an Sr/Ca atomic ratio of 1:9-9:1 and a Bi:(Ca+Sr) atomic ratio of 0.3-1.5. The transition temperature is at least 60 K. The principal phase crystallizes in the orthorhombic system. The pure compounds Bi.sub.4 (Sr,Ca).sub.4 Cu.sub.2 O.apprxeq..sub.12 and Bi.sub.4 (Sr,Ca).sub.6 Cu.sub.4 O.apprxeq..sub.20.

Abstract: The present invention is directed to a process for producing high temperature superconducting ceramic materials. More particularly, the present invention is directed to a process that enhances the densification of Bi.sub.1.8 Pb.sub.0.4 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10 "BSCCO" ceramics.

Abstract: A high-temperature superconductor material based on the Bi--Sr--Ca--Cu--O system has the nominal composition:(Bi.sub.1-u Pb.sub.u).sub.2 (Sr.sub.1-x-y Ca.sub.x Bi.sub.y).sub.4 Cu.sub.3 O.sub.10+d (d=delta)wherein 0.01<x<0.50.ltoreq.y<x<0.50.ltoreq.d0.ltoreq.u.The high-temperature superconductor material has a transition temperature greater than 90.degree. K.

Abstract: A method for preparing a BSCCO-2223 oxide superconducting article includes annealing an oxide superconductor article comprised of BSCCO-2223 oxide superconductor at a temperature selected from the range of about 500.degree. C..ltoreq.T.ltoreq.787.degree. C. and an annealing atmosphere having an oxygen pressure selected from within the region having a lower bound defined by the equation, P.sub.O2 (lower).gtoreq.3.5.times.10.sup.10 exp(-32,000/T+273) and an upper bound defined by the equation, P.sub.O2 (upper).ltoreq.1.1.times.10.sup.12 exp(-32,000/T+273). The article is annealed for a time sufficient to provide at least a 10% increase in critical current density as compared to the critical current density of the pre-anneal oxide superconductor article. An oxide superconductor having the formula Bi.sub.2-y Pb.sub.y Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10+x, where 0.ltoreq.x.ltoreq.1.5 and where 0.ltoreq.y.ltoreq.0.

Abstract: A superconductive material has the formula(Tl.sub.1-X1-X2 Pb.sub.X1 Bi.sub.X2).sub..alpha. (Sr.sub.1-X3 Ba.sub.X3).sub..beta. Ca.sub..gamma. Cu.sub..delta. O.sub..xi.where0.ltoreq.X1.ltoreq.0.80.ltoreq.X2.ltoreq.0.50.ltoreq.X3.ltoreq.1.00.7.ltoreq..alpha..ltoreq.1.51.4.ltoreq..beta..ltoreq.3.00.7.ltoreq..gamma..ltoreq.4.51.4.ltoreq..delta..ltoreq.64.5.ltoreq..xi..ltoreq.170<X1+X2<1.The superconducting material may be combined with an isostructural non-superconducting material, which then acts as a pinning center. The result may also be combined with a metal. The resulting superconductor permits a high critical current density Jc to be obtained, even at relatively high magnetic flux densities.

Abstract: A method is disclosed for fabricating a polycrystalline <223> thallium-containing superconductor having high critical current at elevated temperatures and in the presence of a magnetic field. A powder precursor containing compounds other than thallium is compressed on a substrate. Thallium is incorporated in the densified powder precursor at a high temperature in the presence of a partial pressure of a thallium-containing vapor.

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: A method for preparing an oxide superconductor article includes exposing the article after deformation of the article to a final heat treatment having the steps of (a) heating the article at a temperature sufficient to partially melt the article, such that a liquid phase co-exists with the desired oxide superconductor phase; and (b) cooling to and holding the article at a temperature sufficient to transform the liquid phase into the desired oxide superconductor, where no deformation occurs after the final heat treatment. The liquid phase of step (a) wets surfaces of a defect contained within the mixed phase, whereby upon transformation of the liquid in step (b) to the desired oxide superconductor, the defect is healed.

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: The invention relates to a spray pyrolyric process for the preparation of multi-element metal oxide powders useful as precursors of high temperature superconductor ceramics. Aerosols of aqueous solutions containing corresponding metal salts admixed in the required stoichiometric proportion are sprayed through an independently operated hydrogen/oxygen flame in such a way that a flame temperature of 800.degree.-1100.degree. C. is maintained to form said powders. Any contact of the aerosols and powders generated during the process with carbon or carbon-containing compounds or materials is strictly avoided.

Abstract: A superconductive device for helping shield magnetic field comprises at least two members; a layer containing superconductive oxide over each of said members; means for connecting said members to form a substrate; and means for connecting said layers containing superconductive oxide along a joint in which said members are connected.

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: A perovskite type superconductor film having a high content, almost a single phase, of the high Tc phase is formed by the steps of: depositing at least one first film of a first material (e.g., a composite oxide of Bi-Sr-Ca-Cu-O system or Tl-Ba-Ca-Cu-O system) constituting a perovskite type superconductor over a substrate; depositing at least one second film of a second material containing an oxide or element (Bi.sub.2 O.sub.3, Tl.sub.2 O.sub.3, PbO.sub.x, etc., particularly PbO.sub.x) having a vapor pressure of more than 10.sup.-4 Pa at 800.degree. C. at least as a main component over the substrate; to thereby form a stack of the first and second films; and heat treating the stack of the first and second films to form the perovskite type superconductor film on the substrate. Further, preferred compositions of the as-deposited films or stack are determined.

Abstract: A method of monitoring the fabrication of a superconductive material having a high critical temperature is wherein:the starting material is a mixture of powders of precursors for said material having stoichiometric proportions appropriate for the desired superconductive phase;the said mixture is agglomerated to form a tubular or a cylindrical piece;the agglomerated piece is placed in a controlled-atmosphere oven for synthesizing said superconductive phase;the conductivity of said piece is measured continuously;the temperature at which conductivity begins to decrease is exceeded and then the temperature is returned to a value where conductivity begins to increase; andthe temperature of the oven is permanently adjusted so that said conductivity does not decrease.

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: This invention relates to a process of forming multilayered thallium-containing superconducting composites, wherein a first thallium-containing superconducting layer, an intermediate thallium-containing oxide layer and a second thallium-containing superconducting layer are successively deposited on a substrate by a vapor phase process by controlling the heating temperature, pressure of oxidizing gas and thallium vapor pressure during post-deposition annealing of the superconducting films.

Abstract: Improved superconducting oxides are provided having the general formula (Hg.sub.1-x Tl.sub.x)Ba.sub.2 Ca.sub.n-1 Cu.sub.n O.sub.2n+2+.alpha. where x is from about 0.05-0.5 and n is 1, 2, 3 or 4, and .alpha. is an oxygen enrichment factor. The Tl-doped oxides exhibit very high T.sub.c and J.sub.c values.

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: An oxide-based superconductor ccmprising Tl, Pb, Sr, Ca and Cu or Tl, Pb, Ba, Sr, Ca and Cu, prepared by subjecting a low melting point composition comprising the superconductor-constituting elements and a solid composition comprising the superconductor-constituting elements, prepared in advance, to reaction under melting conditions for the low melting point composition, has distinguished current pass characteristics in a high magnetic field due to improvement of electric contact among grains through reduction of non-superconductor phase, increase in crystal grain sizes (reduction of crystal boundaries), orientation of crystal and cleaning of crystal boundaries.

Abstract: Process for preparing a high-T.sub.c superconductor as a precursor material for the oxide-powder-in-tube method (OPIT). The present invention relates to a process for preparing a high-T.sub.c superconductor as a precursor material for the oxide-powder-in-tube method, which involves mixing the oxides of the elements Bi, Sr, Ca and Cu and completely melting them at temperatures of .gtoreq.1000.degree. C., then casting the melt onto a substrate which is kept at room temperature, and disintegrating the cooled melt block and grinding it into a powder.

Abstract: There is disclosed a method for annealing oxide thin film superconductors having layered structures including at least Cu--O layers in which each oxide thin film superconductor is heated partially by a heating means and the heating portion is moved at a predetermined speed.

Abstract: In accordance this invention, there is provided a process for making a bulk superconductive material. In the first step of this process, a diffusion couple is formed from superconductor oxide and impurity oxide. Thereafter, the diffusion couple is heated to a temperature in excess of 800 degrees Centigrade, cooled at a controlled rate, and annealed.

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: The present invention comprises a high quality, epitaxial thallium-based HTS thin film on MgO and other substrates and methods of providing the same. The present invention is achieved using a nucleation layer which provides a template for subsequent growth. Specifically, YBCO and/or YBCO analog films (films having growth characteristics and physical structures analogous to YBCO) are used as nucleation layer(s) on MgO and other substrates to enable the growth of epitaxial thallium-based HTS films.

Abstract: Mercury-thallium based superconductors with the formula Hg.sub.1-x Tl.sub.x Ba.sub.2 (Ca.sub.1-y Sr.sub.y).sub.2 Cu.sub.3 O.sub.8+.delta. ; change "their preparing method, in particular characterized in that it" to and a method for preparing them. The new superconductors are prepared by reacting respective ternary oxides, such as Ba.sub.2 CuO.sub.3+x and Ca.sub.1-y Sr.sub.y CuO.sub.2, to reduce the formation of an impure phase and by substituting thallium (Ti) a portion of the mercury (Hg) conventionally used in mercury-based superconductors of similar structure, in order to thermally stabilize the superconductor and provide it with a high critical current density characteristic.

Abstract: A method is disclosed for forming polycrystalline thallium system superconductors having high current carrying capacity and high magnetic field behavior. A precursor deposit is formed comprised of silver, in an amount of about 1 to 20 mole percent of total metals in the precursor deposit, and the balance oxides of calcium, barium, and copper in ratios for forming the superconductor. The precursor deposit is annealed in an oxidizing atmosphere, and in the presence of a source of thallous oxide. The source of thallous oxide is heated to a first temperature selected to incorporate thallium into the deposit in an amount of about 6 to 22 mole percent of metals in the superconductor, and the precursor deposit is heated to a second temperature to form the superconductor.

Abstract: Method for the preparation of a precursor for a superconductor, comprising the addition of a condensation product to an aqueous solution of metal salts, the total or partial removal of water from the mixture thus obtained, the subsequent processing of the viscous mass obtained after having removed part of the water or the calcination of the solid gel obtained after having substantially removed all the water, wherein the condensation product is a product of esterification of citric acid with ethylene glycol prepared separately and the solution of metal salts substantially is a solution of acetates in water and acetic acid.

Abstract: The invention relates to a process for producing cylindrical or round parts of high-T.sub.c superconductor material comprising bismuth, strontium, calcium, copper and oxygen. In this process, a pre-prepared finely-divided oxide mixture with organic additives is first introduced at room temperature into a casting mold. The shaped mixture is then converted into the superconducting shaped part by subsequent thermal treatment.

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: Superconducting materials and methods of forming superconducting materials are disclosed. Highly oxidized superconductors are heated at a relatively high temperature so as to release oxygen, which migrates out of the material, and form a non-superconducting phase which does not diffuse out of grains of the material. The material is then reoxidized at a lower temperature, leaving the non-superconducting inclusions inside a superconducting phase. The non-superconducting inclusions act as pinning centers in the superconductor, increasing the critical current thereof.

Abstract: Polycrystalline high-T.sub.c superconductors of the formula M.sub.m E.sub.e RO.sub.x, which contain grains which are crystallographically aligned to the greatest possible extent, where M is at least one trivalent element such as a lanthanide element, E is at least one divalent element such as an alkaline earth element and R is at least one transition metal such as Cu, and x denotes the proportion of oxygen, are obtained by substituting a part of the alkaline earth element by a foreign element, preferably an alkali-metal element, which is no longer present in the product after the reaction sintering and sintering except for contents in the ppm to parts per thousand range and brings about the orientation effect. This produces a material which contains a slight deficit of E and optionally M, has an unaltered critical temperature and is substantially more resistant to external agents than equivalent known materials. A post-treatment in a stream of air or oxygen is unnecessary.

Abstract: To produce a high-temperature superconductor of the composition Bi.sub.2 (Sr,Ca).sub.3 Cu.sub.2 O.sub.8+x having a strontium to calcium ratio of 5:1 to 2:1 and a value of x between 0 and 2, the oxides and/or carbonates of bismuth, strontium, calcium and copper are vigorously mixed in a stoichiometric ratio. The mixture is heated at a temperature of 870.degree. to 1100.degree. C. until a homogeneous melt is obtained. The melt is poured into mold and allowed to solidify in them. The cast bodies removed from the molds are annealed for 6 to 30 hours at 780.degree. to 850.degree. C. Finally, the annealed cast bodies are treated for at least 6 hours at temperatures of 600.degree. to 820.degree. C. in an oxygen atmosphere. The cast bodies can be converted into shaped bodies of the desired sizes by mechanical processes before they are annealed. The shape and size of the shaped bodies may also be determined by the shape and dimensioning of the mold used in producing the cast bodies.

Abstract: A method for manufacturing a Pb-based Cu oxide superconductor. The method includes the steps of mixing powders of a raw material containing at least Pb, Sr, Ce, M, where M is at least one element selected from the group consisting of Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, and Cu in a proportion to have the composition of the formula (I),Pb.sub.a (M.sub.1-x-y Ce.sub.x Sr.sub.y).sub.4 Cu.sub.3-a O.sub.z(I)where M is at least one element selected from the group consisting of Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu, and a, x, y, and z denote the numbers which satisfy 0.3.ltoreq.a.ltoreq.0.7, 0<x.ltoreq.0.25, 0.3.ltoreq.y<0.5, 8.5.ltoreq.z.ltoreq.9.5, respectively, forming the mixed powder into a shaped body, and firing the shaped body at a temperature of 900.degree. to 1150.degree. C. in an oxidizing atmosphere.

Abstract: A ceramic superconductor is produced by close control of oxygen partial pressure during sintering of the material. The resulting microstructure of YBa.sub.2 Cu.sub.3 O.sub.x indicates that sintering kinetics are enhanced at reduced p(O.sub.2) and that because of second phase precipitates, grain growth is prevented. The density of specimens sintered at 910.degree. C. increased from 79 to 94% theoretical when p(O.sub.2) was decreased from 0.1 to 0.0001 MPa. The increase in density with decrease in p(O.sub.2) derives from enhanced sintering kinetics, due to increased defect concentration and decreased activation energy of the rate-controlling species undergoing diffusion. Sintering at 910.degree. C resulted in a fine-grain microstructure, with an average grain size of about 4 .mu.m. Post sintering annealing in a region of stability for the desired phase converts the second phases and limits grain growth.

Abstract: A process for fabricating Thallium-based superconducting tapes comprising the steps of: (1) preparing a powder mixture having a nominal composition of (Tl.sub.1-x-y Bi.sub.y Pb.sub.z)(Ba.sub.2-z Sr.sub.z)Ca.sub.2 Cu.sub.3 O.sub.9 ; (2) placing the powder mixture into a silver tube and drawing and/or swaging the silver tube containing the powder mixture into a wire having a pre-determined diameter, wherein x and y are real numbers between 0.2 and 0.4, and z is a real number between 0 and 2; (3) rolling the wire into a tape having a pre-determined thickness; and (4) subjecting the tape to a two-stage single-sintering process at two respective sintering temperatures. The two-stage single-sintering process of the present invention allows Thallium-based superconducting tapes to be fabricated which exhibit substantially increased critical current density, without causing a substantially increased cost and complexity, as do other prior art processes, such as the double-sintering process.

Abstract: A new class of high temperature superconductive oxides is disclosed. An exemplary member of the class has nominal composition Pb.sub.2 Sr.sub.2 Y.sub.0.5 Ca.sub.0.5 Cu.sub.3 O.sub.8 and has a transition temperature T.sub.c (onset) of about 79K.

Abstract: There is disclosed a process for preparing a thallium-containing superconductive composition. In the first step of the process, a mixture of an inorganic salt (such as potassium chloride) and a powder compositon is provided; the powder composition contains at least three separate compounds which, in combination, correspond to the stoichiometry of the super-conductor to be produced. This mixture is then charged to a closed container, raised to a temperature of from 800-959 degrees Centigrade, and heated for from about 1 to about 12 hours; thereafter, it is cooled to a temperature of 600 degrees Centigrade at a rate of at least 300 degrees Celsius per hour.

Abstract: A method of forming the superconducting body comprises forming a body comprised of a precursor deposit of an oxide superconductor on a substrate formed from a silver alloy comprised of a solute metal from the group consisting of yttrium, aluminum, lithium, zirconium, alkaline earths, lanthanides, and mixtures thereof in an effective amount to form oxide particles that increase the hardness of the substrate, and the balance silver. The body is annealed in an oxidizing atmosphere to form the oxide particles in the substrate, and the deposit into a continuous oxide superconductor.

Abstract: Wire, bulk, film, etc. of a superconductive material is manufactured from a powdery precursor. The superconductive material has a superconductive crystal of 1223 phase and/or 1234 phase as a main component, and the powdery precursor comprises at least 1212 phase as a main component.

Abstract: Unexpected results were obtained when Tl-1223 and Tl=-2223 superconductive materials were annealed at respectively pre-determined annealing temperatures. The optimum annealing temperatures for Tl-1223 and Tl-2223 superconductive materials are found to be 860.degree. C. and 820.degree. C., respectively. By incorporating the optimum annealing temperature and an optimum annealing envirenment, which is expressed in terms of oxygen partial pressure, into the manufacturing process, the present invention presents a method which can substantially increase the critical temperature of thallium based superconductive materials with greatly reduced annealing time and with improved reproducibility, and is thus superior to any method disclosed in the prior art.