Abstract: Composite ceramic mixed ionic and electronic conducting materials having high ambipolar activity which can be fabricated into thin membranes for high efficiency oxygen separation from air at intermediate temperatures. The mixed conducting materials have composite non-homogeneous microstructures of a separate predominantly oxygen ion conductive phase and a predominantly electronic conductive phase. Preferred predominantly oxygen ion conducting phases include bismuth, cerium and zirconium oxide based materials and predominantly electronic conducting phases include at least one metal electronic conductor material.

Abstract: The present invention provides a method for preparing a ceramic mixed-oxide of at least two metals including mixing an alloy with a ceramic oxide. The alloy including a metal selected from the group consisting of aluminum, calcium, lithium, magnesium, silicon, titanium, yttrium, and zirconium. The alloy also includes an element that is to be present in the ceramic mixed-oxide. The element is different from the metal and is selected from the group consisting of aluminum, calcium, lithium, magnesium, a combination of magnesium and silicon, silicon, titanium, yttrium, and zirconium. The ceramic oxide includes a metal that is to be present in the ceramic mixed oxide. The alloy and ceramic oxide are co-milled. The mixed and co-milled alloy and ceramic oxide are reaction-sintered, thereby oxidizing the metal and element of the alloy to produce the ceramic mixed-oxide.

Abstract: A method of forming a highly dispersed ceramic powder slurry is provided prising forming an aqueous based slurry of a ceramic powder and a polyelectrolyte at an acidic pH and adjusting the pH of the slurry to an alkaline value.

Abstract: A self-sintered silicon carbide/carbon-graphite composite material having interconnected pores which may be impregnated, and a raw batch and process for producing the composite material, is provided. The composite material comprises a densified, self-sintered matrix of silicon carbide, carbon-graphite inclusions and small amounts of any residual sintering aids, such as boron and free carbon, and has interconnected pores which may be impregnated with resin, carbon, TEFLON, metal or other compounds or materials selected for their particular properties to achieve desired tribological characteristics for a specific application. The composite material is produced from a raw batch which includes silicon carbide, sintering aids, a temporary filler and coated graphite particles. The raw batch is then molded/shaped into a green body and heated to carbonize any carbonizable materials and to decompose and volatilize the organic filler to form a matrix of interconnected pores.

Abstract: A thermoelectric semiconductor material is disclosed. The material comprises a double oxide which contains antimony and has a trirutile crystal structure.

Abstract: Manganese(III)-containing nickel(II) hydroxide powders produced by coprecipitation carried out by dropping an acidified metal salt solution containing Ni.sup.+2 and Mn.sup.+3 ions into a feed of constant pH value, such that manganese(III) is incorporated into the nickel(II) hydroxide lattice, thereby preventing disproportionation into separate phases and improving performance characteristics of secondary battery electrodes manufactured therefrom.

Abstract: A method for the preparation of tetragonal zirconia polycrystal composite with high toughness and low-temperature degradation resistance. The method comprising adding transformable TZP of ZrO.sub.2 --Y.sub.2 O.sub.3 --Nb.sub.2 O.sub.5 /Ta.sub.2 O.sub.5 system to non-transformable TZP of ZrO.sub.2 --Y.sub.2 O.sub.3 --Nb.sub.2 O.sub.5 /Ta.sub.2 O.sub.5 system in an amount of not more than 60% by weight based on the total weight of the resulting mixture; and sintering the mixture at above 1,500.degree. C. Even though being exposed to a temperature ranging from 100.degree. to 400.degree. C. for a long time in air, the TZP composite prepared by the present method is rarely transformed into monoclinic zirconia and yet exhibits high toughness.

Abstract: A family of mercury-containing Sr-(Ca.cndot.Y)-Cu-O superconducting materials having a zero-resistance temperature, T.sub.c(zero), greater than 90 K so that they can be cooled to and maintain the desired superconducting characteristics using relatively less expensive liquid nitrogen, are disclosed. The high-temperature superconductor is represented by the formula of: (Pb.sub.0.5 Hg.sub.0.5)(Sr.sub.2-x Ba.sub.x)(Ca.sub.0.7 Y.sub.0.3)Cu.sub.2 O.sub.7-.delta. ; wherein the value of x ranges between about 0.1 and about 0.6, preferably between about 0.2 and about 0.3. These superconducting materials are prepared by first grinding and mixing in open air constituent oxide powders of PbO, HgO, SrO.sub.2, BaO.sub.2, CaO, Y.sub.2 O.sub.3, and CuO. After mixing, the powder mixture is pressed under a pressure of about 5 ton/cm.sup.2 to form a pellet having a diameter of 8 mm and a thickness of 3 mm. Thereafter, the pressed pellet is wrapped with a gold foil (with a thickness of 0.

Abstract: A sintering ceramic for stable high-temperature thermistors includes a system of matter containing manganese (IV) and a content of a basic oxide. A method for producing a sintering ceramic for stable high-temperature thermistors includes calcining a mixture of SrCO.sub.3 and Mn.sub.2 O.sub.3 or Mn.sub.3 O.sub.4 ; adding an oxide hydroxide of a dopant in a molar quantity x to an aqueous suspension of the calcined oxide mixture; and then carrying out a compacting densification of the system of matter.

Abstract: Thermodynamically stable ceramic composites are provided for use in high temperature oxidizing environments. A phosphate selected from monazites and xenotimes functions as a weak bond interphase material between the constituents of the composites. Monazite comprises a family of minerals having the form MPO.sub.4, where M is selected from the larger trivalent rare earth elements of the lanthanide series (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, and Tb) and coupled substituted divalents and tetravalents such as Ca or Sr with Zr or Th. Xenotimes are phosphates similar to monazite where M is selected from Sc, Y, and the smaller trivalent rare earth elements of the lanthanide series (Dy, Ho, Er, Tm, Yb, and Lu).

Abstract: Ceramic compositions based on yttrium oxide contain a minor amount of a titanium oxide and are readily sintered into dense ceramic shaped articles well adopted for metallurgical applications.

Abstract: A high temperature superconducting system comprising M--R--Tl--Sr--Cu--O wherein: M is at least one compound selected from the group consisting of Hg, Pb, K, and Al; and R represents rare earth metals. In one embodiment, a composition forms a 93K superconducting phase having the composition: M--R--Tl--Sr--Cu--O wherein: M is selected from the group consisting of Hg and Al; and R is a rare earth metal. In another embodiment, the composition comprises M--R--Tl--Sr--Cu--O wherein: M is selected from the group of Pb and/or K; and R is a rare earth metal.

Abstract: A novel ceramic composite material consisting of single crystal .alpha.-Al.sub.2 O.sub.3 and polycrystal Y.sub.3 Al.sub.5 O.sub.12 and a ceramic composite material consisting of polycrystal .alpha.-Al.sub.2 O.sub.3 and polycrystal Y.sub.3 Al.sub.5 O.sub.12, each having a high mechanical strength and creep behavior particularly at high temperature are provided.

Abstract: A ceramic composite contains one spinel phase and one or more than one oxides phases. The composite is derived from the mixtures of two oxides, A.sub.2 O.sub.3 and BO, with different molar ratio, in which A and B are metallic ions of three and two valences respectively. The oxides are heated at a high temperature to form a composite containing a spinel and residual oxides. The formed spinel and residual oxides also undergo densification under high temperature. After the treatment at high temperature, not only the spinel is formed but also the composite is densified. The performance of the composite is superior in its strength, toughness and high-temperature stability.

Abstract: Oxide-ceramic targets of partially reduced indium oxide-tin oxide mixtures are described. The targets provide high sputter performances, and they exhibit an essentially defined degree of reduction between 0.02 and 0.3, a density between 75 and 98% of the theoretical density and a specific electric resistance between 89.times.10.sup.-3 and 0.25.times.10.sup.-3 .OMEGA. cm. The degree of reduction must not deviate at any point on the target surface by more than 5% from the average degree of reduction of the target. The targets are produced by means of hot-pressing the oxide mixtures which were partially reduced beforehand in a special method step.

Abstract: The strength of a composite sintered body including yttrium oxide is improved. A composite ceramics sintered body includes a matrix of yttrium oxide and silicon carbide particles dispersed within the matrix. A compound oxide phase including yttrium and silicon is present at the surface of the sintered body. A sintered body is obtained by compression-molding mixed powder including yttrium oxide powder and silicon carbide powder in an inert gas atmosphere of at least 1550.degree. C. The sintered body is subjected to a heat treatment for at least 0.5 hour and not more than 12 hours in an atmosphere including oxygen gas in the range of at least 900.degree. C. and less than 1200.degree. C.

Abstract: The invention encompasses a method for manufacturing a high density indium oxide/tin oxide (ITO) sintered body, as well as the ITO sintered body itself. The method produces an ITO sintered body of high homogeneity for use as a sputtering target in manufacturing processes where thin, transparent and electrically conductive ITO layers are deposited over transparent substrates. The method comprises the steps of preparing a slurry whose solid constituents consist of a finely divided mixture of between 99 and 50 weight percent of In.sub.2 O.sub.3 and 1 to 50 weight percent of SnO.sub.2, and between about 0.05 through 0.25 percent of a sintering agent formed from an oxide of, only one of the group consisting of aluminum, magnesium, yttrium, and silicon; forming the resulting slurry into a green body having a density of between about 4.0 and 4.8 gm/c.sup.3 and heating the green body to a sintering temperature of between about 1500 and 1600 C.

Abstract: A porous sintered body composed mainly of lanthanum manganite in which a part of lanthanum atoms at A-sites of the lanthanum manganite are substituted by atoms of a metal selected from the group consisting of alkaline earth metals and rare earth metals. The dimensional shrinkage amount of the porous sintered body in heat cycling between room temperature and 1,000.degree. C. is not more than 0.01% per one heat cycle.

Abstract: A dense, self-sintered silicon carbide/carbon-graphite composite material and a process for producing the composite material is disclosed. The composite material comprises a silicon carbide matrix, between 2 and 30 percent by weight carbon-graphite, and small amounts of sintering aids such as boron and free carbon. The silicon carbide has an average grain size between 2 and 15 .mu.m, and the carbon-graphite has an average grain size between 10 and 75 .mu.m, the average grain size of the carbon-graphite being greater than the average grain size of the silicon carbide. The composite material has a density of at least 80 percent of theoretical density as determined by the rule of mixtures for a composite material. This density is achieved with minimal microcracking at a high graphite loading with large graphite particles. The composite material exhibits good lubricity and wear characteristics, resulting in improved tribological performance.

Abstract: A process for preparing red ceramic molded bodies by rapid firing is disclosed, wherein low Si-content iron oxides are employed. The process produces molded bodies having improved colouristic properties.

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: An ITO sintered body according to the present invention has a density thereof of between 90 and 100% and a sintering particle size of between 1 and 20 .mu.m. A proportion of (In.sub.0.6 Sn.sub.0.4).sub.2 O.sub.3 in the ITO sintered body is 10% or below. Such an ITO sintered body is manufactured by mixing an indium oxide powder, whose BET surface area is between 15 and 30 m.sup.2 /g, a BET size/a crystallite size is 2 or below, and an average primary particle size is between 0.03 and 0.1 .mu.m, with tin oxide whose BET surface area is 3 m.sup.2 /g or below, and then by sintering the mixture.

Abstract: A method for improving the properties of ceramic green bodies is provided. In particular, ceramic green bodies having improved green strength are provided. Incorporating certain acid-containing polymers as binders at a level of at least about 1 to about 15, preferably at least about 3 to about 10 percent by weight based on the weight of ceramic particles improves the green strength of the resulting ceramic green bodies.

Abstract: This invention relates to a shaped fibrous material for use in the manufacture of fiber-reinforced metals comprising a uniform mixture of ceramic fibers and aluminum borate whiskers. The invention also relates to a method for producing the shaped fibrous material comprising the steps of dispersing ceramic fibers and aluminum borate whiskers in a suitable solvent containing a binder to form a slurry, transferring the slurry into a suction molding, aspirating and dehydrating the slurry to form a shaped dehydrated fibrous material, and drying and firing the shaped dehydrated fibrous material to obtain the shaped fibrous material. The shaped fibrous material can be cast efficiently into a fiber-reinforced metal with a high yield. The thus produced fiber-reinforced metal has a high wear resistance combined with a very mild nature of attacking the mating member.

Abstract: A sintered body of silicon nitride base solidly formed of interior and surface portions wherein the rate of decrease of the content Si or Si.sub.3 N.sub.4 and Sialon grains in the surface portion, with respect to that in the interior portion, is not less than 20% by weight or 30-100 vol %, respectively. The grain boundary phase of the surface portion is glassy, or crystallized partly or entirely. Crystallized boundary phase comprises Si.sub.3 N.sub.4 -Y.sub.2 O.sub.3 base compounds Si.sub.3 N.sub.4 -nY.sub.2 O.sub.3 -mX (n=1-5, X=SiO.sub.2, Al.sub.2 O.sub.3, m=0-4) such as mellilite, J phase (mohlerite), K phase (wollastonite), H phase (apatite), or A phase (Si.sub.3 N.sub.4.5Y.sub.2 O.sub.3.Al.sub.2 O.sub.3). Sintering aids of Al.sub.2 O.sub.3, Y.sub.2 O.sub.3, AlN, MgO, CaO, Y.sub.2 O.sub.3 and/or rare earth oxides form boundary phases.

Abstract: A high-Tc oxide superconductor including Bi, Sr, Ca, Cu, O and at least one of Pb and Al, with a high critical temperature than that of liquid nitrogen. A method for producing the high-Tx oxide superconductor is also disclosed, in which Bi.sub.2 O.sub.3, SrCO.sub.3, CaCO.sub.3, CuO and PbO or Al.sub.2 O.sub.3 powders are mixed, calcined, ground, cold-pressed and sintered. The calcined mixture may be melted and annealed to obtain a tape-form superconductor.

Abstract: A substrate material for the preparation of an oxide superconductor includes two different rare earth elements A' and A" in the IIIa group, Ga, and 0, the atomic ratio of these elements being expressed as A'1-xA"xGaO.sub.3 (where 0<x<1), and a mixed crystal material forming a perovskite-type structure having a composition of AGaO.sub.3 with A being at least one of the two rare earth elements A' and A" in the IIIa group, a substrate material for preparing an oxide superconductor includes a mixed crystal material made up of Nd, La, Ga, and O in an atomic ratio of La.sub.1-x Nd.sub.x GaO.sub.3 wherein 0.2.ltoreq.x<1.0, the substrate material forming a GdFeO.sub.3 -type structure; a substrate material for preparing an oxide superconductor includes a mixed material made up of Nd, A.sup.1, Ga, and O in an atomic ratio of A.sup.1.sub.1-x Nd.sub.x GaO.sub.3 where A.sup.1 is a rare earth element excluding La and Nd, and 0.2.ltoreq.x<1.0, the mixed crystal material forming a GdFeO.sub.3 -type structure.

Abstract: A method of growing mixed crystals having at least two lattice sites each having a different number of adjacent oxygen ions from melts of oxidic multi-component systems, homogeneous mixed crystals being grown such that the cations intended to occupy the first lattice site having the highest number of adjacent oxygen ions and to occupy the second lattice site having the next lowest number of adjacent oxygen ions are chosen such that the ratio of the bond length of the cations in the first lattice site to the bond length of the cations in the second lattice site is in the range from 0.7 to 1.5.

Abstract: A lanthanum chromite ceramic powder consisting essentially of 1 mol of LaCr.sub.1-x M.sub.x O.sub.3, where M is a divalent metal selected from the group of zinc, copper and mixtures thereof and x ranges from about 0.02 to 0.2, y mols of B.sub.2 O.sub.3, where y ranges from 0.0005 to 0.04, and z mols of La.sub.2 O.sub.3, where the ratio z/y ranges from 1 to 3, the powder is sintered to high density by firing a compact thereof at a temperature of about 1400.degree. C. in air or other atmosphere, and is particularly suited for use as interconnect material for solid oxide fuel cells.

Abstract: A sinter-reactive lanthanum chromite powder is prepared from the lanthanum chromite precursor LaCr.sub.1-x M.sub.x O.sub.3 (Adsorbate). The powder is crystalline, has the formula LaCr.sub.1-x M.sub.x O.sub.3, where M is selected from the group consisting of zinc, copper and mixtures thereof and x ranges from about 0.02 to 0.2, and sinters to densities higher than about 95% of theoretical density at temperature as low as 1400.degree. C. in oxidizing atmospheres. Sintering to such high density at temperatures in the vicinity of 1400.degree. C. makes the powder particularly suited for use as interconnect material for solid oxide fuel cells.

Abstract: Disclosed are an oxide superconductor, and an optimum process for producing the same. The oxide superconductor comprises a base material phase including an oxide superconducting material, the oxide superconducting material including barium (Ba) at least and being free from grain boundaries, and precipitation phases contained in an amount of 1 to 50% by volume in the base material phase and dotted therein in a manner like islands, the precipitation phases being oxides of a metal selected from the group consisting of silicon (Si), aluminum (Al), zirconium (Zr), magnesium (Mg), titanium (Ti), strontium (Sr), tungsten (W), cobalt (Co) and vanadium (V), and being products of decomposition reaction of the base material phase. In the production process, the constituent materials are treated thermally at a partially melting temperature in order to give the above-described novel structure to the oxide superconductor.

Abstract: A moulding compound is described which contains an inorganic powder together with a binder system. The binder system contains a thermoplast having a melting temperature greater than 180.degree. C. A process is also described for making a sintered molding from the molding compound, which process includes the steps of injection moulding, removal of the binder by heating, and sintering.

Abstract: A method of manufacturing a component of the tape or filament kind out of a material based on a superconducting oxide having a high critical temperature, wherein said material is formed while it is in the vitreous state,the method being characterized by the fact that the material is subsequently crystallized:in a first step under a magnetic field and at a temperature T.sub.l lying between the vitreous transition temperature T.sub.g and the crystallization temperature T.sub.x, during which step isolated microcrystallites of submicroscopic size develop and their c axes orient themselves parallel to one another because of said applied magnetic field; andin a second step at a temperature T.sub.2 close to the crystallization temperature, in which the existing nuclei grow while retaining the texture imparted to them during said first step.

Abstract: The present invention relates to a novel method of manufacturing a composite body, such as a ZrB.sub.2 --ZrC--Zr composite body, by utilizing a post-treatment technique which may improve the oxidation resistance of the composite body. Moreover, the invention relates to novel products made according to the process. The novel process modifies at least a portion of a composite body by exposing said body to a source of second metal.

Abstract: Mixed oxygen ion and electronic conducting bismuth oxide based ceramic materials having high ambipolar activity which can be fabricated into thin membranes for high efficiency oxygen separation from air at intermediate temperatures. The ceramic materials may be homogeneous microstructures in the form of solid solutions or compounds or may be composite non-homogeneous microstructures of a separate substantially continuous oxygen ion conductive phase and a substantially continuous electronic conductive phase.

Abstract: A voltage non-linear resistor element mainly including ZnO, substantially free from internal defects, exhibiting an excellent current impulse withstand capability, can be manufactured by a process wherein an SiC inclusion in the starting ZnO powder is restricted to at most 10 ppm, preferably at most 0.1 ppm, by weight, whereby formation of closed pores in the element is prevented, which is otherwise caused by decomposition of considerable amount of SiC during firing. The starting ZnO powder has an average particle diameter (R) of 0.1-2.0 .mu.m, preferably 0.3-0.8 .mu.m, a particle size distribution within the range of between 0.5R and 2R, of at least 70%, preferably 80%, by weight, needle-like crystals of at most 20%, preferably at most 10%, by weight, and an SiC content as an impurity of at most 10 ppm, preferably at most 0.1 ppm, by weight.

Abstract: A granular abrasive material is produced from a dispersion consisting of raw materials containing alumina, compounds containing silica and other additives. The dispersion is ground to a sinterable slip with a grain size of less than 1 micrometer. The slip is dried and may be pressed before being subjected to a multi-stage heating process to produce sintered corundum crystals.

Abstract: A method of manufacturing ferrite crystals such as single crystal bodies and polycrystal bodies with garnet structure is disclosed, which includes the steps of effecting a composition controlling for raw powders, forming raw powders, sintering formed bodies and effecting hot isostatic press treatment for sintered bodies. Also, a method of producing ferrite powders preferably used for the ferrite crystal manufacturing method mentioned above.The thus obtained ferrite crystal bodies with garnet structure show good magnetooptical properties such as light transmissivity, Faraday rotation angle and Verdet constant, and are preferably used for magnetooptical elements such as optical isolators and optical magnetic field sensors etc.

Abstract: Ceramic binder for forming and processing ceramic ware, comprising a sol-gel of a mixture of highly charged metal hydroxy cations and one or more low charged metal hydroxy cations, which are able to form an aqueous sol.

Abstract: Complex superconducting oxides are fabricated through appropriate selection and use of fundamental superconducting "building blocks." In this fashion, the invention provides a rationalized method of fabricating complex oxides having desirably high T.sub.c values. In another aspect of the invention, novel, 112 and 12 superconducting oxides are described.

Abstract: Self-supporting bodies are produced by reactive infiltration of a parent metal into a boron donor material and a carbon donor material. The reactive infiltration typically results in a composite comprising a boron-containing compound, a carbon-containing compound and residual metal, if desired. The mass to be infiltrated may contain one or more inert fillers admixed with the boron donor material and carbon donor material. The relative amounts of reactants and process conditions may be altered or controlled to yield a body containing a wide ranging varying volume percentage of ceramic, metal, and porosity.

Abstract: 1. In the (Bi,Tl)-Ca-(Sr,Ba)-Cu-O based superconducting ceramics production process, a process for preparing superconducting ceramics characterized by(a) providing powders includingi) a compound of Bi oxide or Tl oxide,ii) a Ca compound,iii) an Sr compound or Ba compound, andiv) a Cu compoundas starting powders;(b) compounding and mixing powders from compounds of the starting powders, the compounds each having lower vapor pressure, i.e., powders from compound ii), compound iii), and compound iv) at a compounding ratio to obtain a mixture, and primarily calcining the mixture at a temperature of 850.degree. to 1050.degree. C., to form a Ca--(Sr,Ba)--Cu--O based oxide; and(c) further mixing the Ca--(Sr,Ba)--Cu--O based oxide with a compound having a higher vapor pressure, that is, the powder of compound i), at a compounding ratio, and secondarily calcining at a temperature of 500.degree. to 820.degree. C.

Abstract: A Bi-Pb-Sr-Ca-Cu-O system superconductor having a composition ofBi.sub.n Pb.sub.m Sr.sub.x Ca.sub.y Cu.sub.2 O.sub..delta.wherein n is a number from 0.76 to 1.05, m is a number from 0.01 to 0.20, x is a number from 0.85 to 1.35 and y is a number larger than 1.00 and not larger than 1.35; or n is a number larger than 1.06 and not larger than 1.15, m is a number from 0.12 to 0.25, x is a number from 1.20 to 1.35 and y is a number from 1.20 to 1.30; or n is a number larger than 0.75 and not larger than 1.15, m is a number from 0.25 to 0.35, x is a number from 1.20 to 1.35 and y is a number from 1.20 to 1.35, when they are normalized with the Cu mole number of 2, which has t.sub.c of at least 110 K.

Abstract: An improved voltage non-linear resistor having a superior voltage-current characteristic property, a superior switching current impulse withstand capability, a superior lightning current impulse withstand capability, and a large discharge voltage V.sub.0.1mA of 230-330 V/mm, a small deterioration rate of the discharge voltage V.sub.0.1mA after applying a lightning current impulse, a prolonged electric life under electrical stress and an improved discharged voltage at a large current area is provided which contains zinc oxide as a main component, and desired amounts of subsidiary components of bismuth oxide, cobalt oxide, manganese oxide, antimony oxide, chromium oxide, silicon oxide, nickel oxide, aluminum oxide, boron oxide and silver oxide. The resistor has a discharge voltage of V.sub.0.1mA of 230-330 V/mm at a current density of 0.1 mA/cm.sup.2 calculated per unit thickness of the sintered resistor, a discharge voltage ration V.sub.10A /V.sub.0.1mA of 1.2-1.45 a current densities of 10 A/cm.sup.2 and 0.

Abstract: A vacuum switch contact material consists essentially of a mixture of Cu and Cr.sub.x O.sub.y (x=1 to 2, y=0 to 3) wherein Cr.sub.x O.sub.y is in a particulate state, the center part of the particles consists of Cr.sub.2 O.sub.3 (x=2, y=3), and the peripheral part of the particles consists of Cr (x=1, y=0). The Cr.sub.x O.sub.y particles having Cr.sub.2 O.sub.3 central part and Cr periphery can be formed by reducing the surface of Cr.sub.2 O.sub.3 particles. Cu may be infiltrated into the open pores of Cr.sub.x O.sub.y particles after a green compact of Cr.sub.2 O.sub.3 is formed. Alternatively, a mixture of Cr.sub.2 O.sub.y particles and Cu particles may be formed into a green compact, which may then be sintered. Still alternatively, a mixture of Cr.sub.2 O.sub.y particles and Cu particles may be hot-pressed.

Abstract: Reactive metals, such as titanium or nickel-chrome superalloys containing rare earths, are cast with mold and/or core surface areas formed from an improved slurry. The improved slurry contains yttria to form an inert surface which is exposed to the molten reactive metal. In order to prevent premature gelation of the slurry, the forming of defects in the mold and/or core surface areas, and the forming of defects in the cast article, the slurry contains a source of hydroxyl ions. The source of hydroxyl ions is sufficient to result in the slurry having a pH of at least 10.2 six days after initially mixing the slurry. The source of hydroxyl ions may be a metal alkali or an organic hydroxide. It is believed that the source of hydroxyl ions functions as a hydration suppressant for the yttria to prevent premature gelation of the slurry. The slurry contains a silicon oxide (SiO.sub.2) to alkali ratio which is equivalent to a silicon oxide to sodium oxide (Na.sub.

Abstract: The present invention provides a composition of dielectric ceramic composition to be used in the frequency region of microwaves.The composition contains lead oxide, calcium oxide, iron, oxide, tantalum oxide and niobium oxide, and is represented by (Pb.sub.1-x Ca.sub.x).sub.1+a {Fe.sub.178 (Ta.sub.1-y Nb.sub.y).sub.178 }O.sub.3+a wherein x, y and a satisfy, respectively, 0.44.ltoreq.x.ltoreq.0.63, 0.0.ltoreq.y.ltoreq.1.0 and 0.0.ltoreq.a.ltoreq.0.08.

Abstract: The present invention provides an oxide superconductor which has a relatively high transition temperature T.sub.c. This superconductor has the chemical formula (R.sub.1-x Ca.sub.x)(Ba.sub.1-y Sr.sub.y).sub.2 Cu.sub.3 O.sub.7-z wherein R is at least one rare earth element selected from the group consisting of Tm, Yb and Lu, x is with in the range of 0.1.ltoreq..times.0.5, y is within the range of 0.1.ltoreq. y .ltoreq.0.4 and z is within the range of 0.05 .ltoreq. z .ltoreq.(x/2+0.5). The invention further provides a method for producing the oxide superconductor which comprises firing a composition of the formula (R.sub.1-x Ca.sub.x)(Ba.sub.1-y Sr.sub.y).sub.2 Cu.sub.3 O.sub.7-z wherein R is at least one rare earth element selected from the group consisting of Tm, Yb and Lu, x is within the range of 0.1 .ltoreq..times..ltoreq.0.5 and y is within the range of 0.1 .ltoreq.y .ltoreq.0.4 at a temperature of from 750.degree. C. to the melting temperature of the composition under an oxygen partial pressure P(O.sub.

Abstract: Novel superconducting oxide compositions of the formulas (YBa.sub.2 Cu.sub.3.25).sub.a O.sub.z and Y.sub.2 Ba.sub.4 Cu.sub.8 O.sub.20-x (248) are provided which can have an ordered defect structure stacked on one axis. MiThis invention was made with Government support under contracts DMR-8616055 awarded by the National Science Foundation and F49620-88C-0004 awarded by the United States Air Force. The Government has certain rights in this invention.

Abstract: A machinable high Tc ceramic superconductor is formed by weighing and mixing appropriate stoichiometric amounts of Bi.sub.2 O.sub.3, SrCO.sub.3, CaCO.sub.3, and CuO (BSCCO), removing carbonates from the mixture, melting the mixture, casting the melted mixture into a mold, and inducing superconductivity and growth of randomly oriented platelets in the cast.