Abstract: An improved polycrystalline semiconducting ceramic composition comprises an alkaline earth metal titanate doped with a hexavalent metal oxide such as (MO.sub.3)(Bi.sub.2 O.sub.3).sub.x where M is tungsten or molybdenum, and x ranges from 0 to 7, which is liquid phase sintered with lead germanate to produce internal insulating boundaries. The composition is fine grained and provides thin-layer, multi-layer capacitors that exhibit high dielectric constant values, low dissipation factors, and low temperature and voltage coefficients of capacitance.

Abstract: A method for producing piezoelectric ceramics of a Pb(Sn.sub..alpha. Sb.sub.1-.alpha.)O.sub.3 -PbTiO.sub.3 system is disclosed which comprises providing a piezoelectric ceramic composition expressed by the general formula:xPb(Sn.sub..alpha. Sb.sub.1-.alpha.)O.sub.3 -PbTiO.sub.3wherein subscripts .alpha., x and y are mole fractions of the respective components and have the following values, x+y=1.00, 1/4.ltoreq..alpha..ltoreq.3/4, 0.01.ltoreq.x.ltoreq.0.40, and 0.60.ltoreq.y.ltoreq.0.99, forming powder of the composition into forming bodies, and firing the forming bodies in an oxygen atmosphere containing not less than 80 vol % of oxygen. The firing in the oxygen atmosphere is effected at a temperature not less than 1000.degree. C. A part of lead in the composition may be replaced with not more than 20 atomic percent of at least one metal selected from the group consisting of Ba, Ca, Sr and Cd. The composition may contain a small amount of Mn, Mg and/or Cr.

Abstract: Multilayer capacitors of good electrical properties can be made by firing, in air at low temperatures, certain modified lead titanate dielectric compositions. The dielectric compositions have the formula(Sr.sub.x Pb.sub.1-x TiO.sub.3).sub.a (PbMg.sub.0.5 W.sub.0.5 O.sub.3).sub.bwhereinx is 0-0.10,a is 0.35-0.5,b is 0.5-0.65, anda plus b equals one.

Abstract: A dielectric ceramic composition consists essentially of strontium titanate, magnesium titanate, bismuth oxide, titanium oxide, and lead oxide, these components being present in the following compositional proportion when expressed by the formulas, SrTiO.sub.3, MgTiO.sub.3, Bi.sub.2 O.sub.3, TiO.sub.2 and Pb.sub.3 O.sub.4, respectively:______________________________________ SrTiO.sub.3 30.0-60.0 wt % MgTiO.sub.3 2.0-32.0 wt % Bi.sub.2 O.sub.3 10.0-34.0 wt % TiO.sub.2 3.0-15.0 wt % Pb.sub.3 O.sub.4 2.0-20.0 wt % Pb.sub.3 O.sub.4 /MgTiO.sub.3 0.625-10.0 (weight ratio) ______________________________________The composition exhibits high permittivity, small dielectric loss, small dependency of permittivity on temperature, and high dielectric breakdown voltage in combination, so that it makes it possible to produce physically small capacitors with large capacity and high rating voltage. The process for production of the composition is characterized by the use of MgTiO.sub.3 and Pb.sub.3 O.sub.

Abstract: Method for producing a dielectric having perowskite structure comprising stoichiometric alkaline earth titanates, alkaline earth zirconates, alkaline earth stannates and mixed crystals thereof, wherein an admixture of eutectic-forming compounds which are capable of forming CuO.MeO.sub.x when sintered in an oxygen atmosphere, which cannot in practice be built into the perowskite lattice, are added to the stoichiometric perowskite structure and wherein the mixture of compounds is sintered at a partial oxygen pressure of 0.2 to 1 Bar in the temperature range from 1000.degree.-1250.degree. C., MeO.sub.x in the above-mentioned formula being the oxide of at least one element of group III, V, VI or VII of the Periodic System of Elements (P.S.E.).

Abstract: The product and process of making an in-vivo body implant pharmaceutical carrier of a resorbable ceramic crystalline structure of interconnecting pores capable of the critical controlled time release of pharmaceutical preparations such as proteins, polypeptides, hormones, and other small molecular weight active materials. The ceramic is comprised of aluminum oxide (Al.sub.2 O.sub.3), calcium oxide (CaO), and phosphorous pentoxide (P.sub.2 O.sub.5) in a controlled weight percent mixture. In the process of making, the mixture is calcined. The calcined mixture is again ground and sieved through screens of two different mesh sizes to obtain desired sizes and mixed with a binder. This mixture is compressed and sintered at a predetermined temperature. The particle sizes of the sieved calcined compound and the sintering temperatures are interrelated to provide a ceramic of a desired pore size for the controlled release of the pharmaceutical.

Abstract: The ductility of sintered bodies of alumina and like hard substances can be improved without loss in mechanical strength by uniformly distributed individual particles of tetragonal zirconia or hafnia in amounts of 1%-50% by volume if the dispersed particles have an average size of 0.05 to 2 .mu.m.

Abstract: High purity, fine Si.sub.3 N.sub.4 powder produced by the vapor phase reaction of SiCl.sub.4 with NH.sub.3 is amorphous. The crystallization rate of the amorphous powder is enhanced by heating the powder while in intimate contact with a titanium containing material, for example, TiN codeposited with the Si.sub.3 N.sub.4 by the simultaneous reaction of TiCl.sub.4 with NH.sub.3.

Abstract: Titanates of zinc and/or alkaline earth metals are produced by simultaneously adding to a suspension of finely divided TiO.sub.2, maintained at a substantially constant pH above about 8, a solution of a salt of zinc and/or alkaline earth metal and alkali to form a hydroxide precipitate. Filtration produces a filter cake mixture of TiO.sub.2 and hydroxide and calcination at above 500.degree. C. produces the desired titanate of narrow particle size distribution and desirable optical properties. Non-simultaneous addition results in a non-filterable material. Zinc, magnesium and/or calcium are preferred and doping elements such as aluminum, phosphorus, boron and/or silicon may also be present.

Abstract: Solid, shaped and fired refractory articles, such as fibers and microspheres, of titanium dioxide are made by shaping, gelling, and firing titania sols. Said fibers can be made by extruding in air a viscous aqueous titania sol, and heating and firing the resulting green fiber to remove water, decompose and volatilize undesired constituents, and form a refractory fiber of polycrystalline titanium dioxide, which is useful, for example, to form refractory fabrics or as reinforcement for composites. Said microspheres can be made by dispersing droplets of an aqueous titania sol in an organic dehydrating liquid, separating the resulting green microspheres from the dehydrating liquid, and heating and firing the green microspheres to form solid refractory microspheres of polycrystalline titanium dioxide, which are useful, for example, in reflective signs or traffic marking surfaces.

Abstract: Dielectrics without any residual magnetization, produced by the technique of ceramics sintered at high temperatures, usable in devices operating at very high frequencies, such as X band. They are obtained by sintering at lower temperatures than for known dielectrics suitable for those applications and correspond to two possible general formulae:Y.sub.3-x-z Ca.sub.x+z Zr.sub.x Fe.sub.5-x-y-z Al.sub.y Me.sub.z O.sub.12where:Me= Ge, Si or Ti;x is of the order of 20.ltoreq. y.ltoreq. 20.ltoreq. z.ltoreq. 1And (1+ Y)Li.sub. 2 O; 2xZnO; (2x+ 4y)TiO.sub.2 with: 1- 0.4x- 0.6y= 0.

Abstract: Sodium chloride and/or potassium chloride is added to an aqueous suspension of the oxides of lead, titanium, zirconium and cationic modifier and stirred until the suspension converts to a gel which is then heated, evaporating the water and melting said chloride in which the oxides dissolve and react precipitating modified lead zirconium titanate.

Abstract: Sodium chloride and/or potassium chloride is added to an aqueous suspension of the oxides of lead, titanium and zirconium and stirred until the suspension converts to a gel which is then heated evaporating the water and melting said chloride in which the oxides dissolve and react precipitating lead zirconate titanate.

Abstract: Printed circuits are produced on an insulating substrate by electroless metal plating according to a method comprising steps of:(I) forming a plating resist on a negative pattern of circuit with a masking material having an effect upon reducing the deposition of an initiator for electroless metal plating, and depositing the initiator onto the entire surface of the insulating substrate,(II) removing the initiator from the surface of said resist, and(III) dipping the insulating substrate in an electroless metal plating solution, thereby forming an electroless metal plating on a positive pattern of circuit, wherein a thermosetting resin containing a rutile type solid solution of metal oxides of titanium, nickel and antimony is employed as the masking material in said step (I), and the initiator is removed from the surface of the resist through contact with a hydrochloric acid solution of ammonium persulfate in said step (II).

Abstract: A polycrystalline article is densified to provide either a nonporous body or a body with controlled interconnected porosity. A mixture of fine powders of the polycrystalline material and a sintering aid is compacted and outgassed under reduced pressure. The outgassed compact is then subjected to a permeation anneal step in which it is heated in a closed chamber to a temperature sufficient to form a liquid of the sintering aid, but under pressure conditions which inhibit evaporation of the sintering aid. The sintering aid can then be leached out to provide a densified article having interconnected porosity. Alternatively, the sintering aid can be leached out at elevated temperature, further densifying the compact to form a substantially nonporous body. Alternatively, the sintering aid can be removed by subjecting the densified article to an evaporation anneal step in which the article is heated to evaporate the sintering aid, further densifying the compact to form a substantially nonporous article.

Abstract: High purity, fine Si.sub.3 N.sub.4 powder produced by the vapor phase reaction of SiCl.sub.4 with NH.sub.3 is amorphous. The crystallization rate of the amorphous powder is enhanced by heating the powder while in intimate contact with a titanium containing material, for example, TiN codeposited with the Si.sub.3 N.sub.4 by the simultaneous reaction of TiCl.sub.4 with NH.sub.3.

Abstract: A composition consisting of 5 to 95 mol% of bismuth oxide (Bi.sub.2 O.sub.3) and 95 to 5 mol% of copper oxide (Cu.sub.2 O), or a composition consisting of 50 to 95 mol% of copper oxide (Cu.sub.2 O) and 50 to 5 mol% of manganese dioxide (MnO.sub.2), or a composition consisting of 5 to 95 mol% of bismuth oxide (Bi.sub.2 O.sub.3) and 95 to 5 mol% of manganese dioxide (MnO.sub.2), is thermally diffused in the grain boundaries of semiconductor ceramics composed mainly of strontium titanate (SrTiO.sub.3) to form highly insulating layers in the grain boundaries to thereby provide semiconductive ceramics wherein the rate of change of dielectric constant with temperature as well as the dielectric loss (tan .delta.) are smaller than in the conventional barium titanate type semiconductor products. Further, the insulation resistance is higher than in the conventional product.

Abstract: A sintered compact of boron nitride with high density form having high oxidation resistance, water resistance, compressive strength and hardness can be obtained by sintering wurtzite-structured boron nitride together with a boride of titanium, zirconium or hafnium, or with mixtures thereof under a condition of high temperature and high pressure.

Abstract: Strengthened and densified ceramic bodies are produced by hot pressing lead itanate powder into a lead titanate ceramic at a pressure from 1000 to 5000 psi and at a temperature from 700 to 1100.degree. C if the atmosphere is reducing or from 700 to 1200.degree. C if the atmosphere is oxidizing and by annealing the lead titanate ceramic at a temperature from 600 to 1100.degree. C in an oxidizing atmosphere for at least four hours.

Abstract: Powders of barium titanate, of an alkaline-earth-zirconate and of a cadmium containing glass are mixed with an organic binder to form a body that is subsequently fired at from 1800.degree. F to 2050.degree. F to make a glass-reacted-ceramic dielectric having a glass phase intermixed with a single titanate-zirconate phase. The omission of the conventional calcining step to obtain the single phase titanate-zirconate results in a substantial cost saving.

Abstract: A pulse generator comprising an induction element, and a nonlinear condenser whose dielectric material portion is made of ferroelectric ceramics represented by a general formula of (Pb.sub.1-x-y, Ba.sub.x, Sr.sub.y)(Ti.sub.z, Zr.sub.1-z)O.sub.3.

Abstract: A ceramic dielectric composition is provided including 35 to 93.5% by weight of SrTiO.sub.3, 4 to 40% by weight of Bi.sub.2 O.sub.3, at least 2.5% but less than 60% by weight of TiO.sub.2, and 0.1 to 5.0% by weight, of an alkali metal oxide based on the total amount of SrTiO.sub.3, Bi.sub.2 O.sub.3 and TiO.sub.2. The ceramic dielectric composition has a high dielectric constant and low dielectric loss and exhibits reduced variations of dielectric constant and the dielectric loss with respect to variation of an applied voltage.

Abstract: A sealing composition which can be suitably used for sealing a panel and a funnel of a color television tube is disclosed. The composition consists essentially of 60 - 99 wt.% of low melting devitrifiable glass powder, 1 - 35 wt.% of lead titanate powder and 0 - 5 wt.% of zircon powder. The glass powder has a composition of 77 - 83 wt.% of PbO, 7 - 10 wt.% of B.sub.2 O.sub.3, 7 - 12 wt.% of ZnO and 1 - 3 wt.% of SiO.sub.2.

Abstract: A ceramic capacitor operatively connected to a piezoelectric oscillator for compensating for the temperature dependence of the oscillator frequency is provided for thereby optimizing the accuracy of an electronic timepiece.

Abstract: Refractory metal diboride articles having an overall density of 50-90 percent of theoretical and a matrix of near theoretical density, e.g., 95-99 percent are described. They may be made by cold pressing and sintering an intimate mixture of submicron Group IVb metal diboride powder and finely divided solid hydrocarbon, e.g., microcrystalline petroleum wax. The hydrocarbon remains particulate in the cold pressed piece but is driven out by heat at the beginning of the sintering operation, thereby leaving voids which remain as gross pores surrounded by a dense matrix in the sintered article. Submicron boride powders capable of forming the dense matrix contain a minor proportion of a sintering or densifying aid such as carbon or a metal carbide such as titanium carbide, tungsten carbide, or boron carbide. The articles so produced are lighter in weight than non-porous articles of the same size, have high electrical conductivity and, by virtue of the dense matrix, have excellent resistance to chemical attack.

Abstract: The invention concerns a densely sintered ceramic dielectric with a loss factor less than or equal to 1.times.10.sup.-3 and a substantially linear temperature dependence of the capacitance based on TiO.sub.2 and/or ZrO.sub.2, and/or the compounds of TiO.sub.2, ZrO, Nb.sub.2 O.sub.5 and/or Ta.sub.2 O.sub.5 with oxides of the alkali metals, alkaline earth metals or rare earth metals in the form generally used for the production of ceramic dielectrics.

Abstract: A process for producing ceramics to be used as substrates and packages of semiconductor devices, which having a thermal expansion coefficient close to that of silicon used as chip or wafer material of large scale integrations and a mechanical strength and thermal conductivity equal to those of alumina, wherein zircon and clays such as kaolin, ball clay and the like and an additive of one of Li.sub.2 O, TiO.sub.2 and ZnO and another of CoO, Co.sub.2 O.sub.3, Co.sub.3 O.sub.4 and MgO are mixed, molded and fired.

Abstract: A dielectric ceramic composition for high frequencies consisting essentially of 83 to 99.8 wt% of a basic composition composed of 22 to 43 wt% of titanium dioxide, 38 to 58 wt% of zirconium dioxide and 9 to 26 wt% of stannic oxide, and 0.2 to 17 wt% of one or two addditives selected from the group consisting of lanthanum oxide, cobaltic oxide and zinc oxide. The dielectric ceramic composition has high permittivity and high Q and is suitable for use as dielectric resonators in microwave bandpass filters, or as antennas employed at microwave frequencies, or as substrates for microwave circuits.

Abstract: The method including blending 90 parts by weight titanium diboride and 10 parts by weight boron nitride, cold isostatically pressing the blend to a shape at 60,000 pounds per square inch pressure, and sintering the shape at 1975.degree. C in an inert atmosphere.

Abstract: A magnesia ceramic for high-frequency electric insulation is produced by using, as the principal component, magnesia and adding thereto a calcium-magnesium-phosphate and at least one member selected from the group consisting of the oxides of aluminum, silicon, beryllium and tungsten.

Abstract: An improved reduction-reoxidation type semiconducting ceramic capacitor and the method for producing the same are disclosed. The main components of the substrate of the capacitor are CaTiO.sub.3, SrTiO.sub.3 and Bi.sub.2 O.sub.3 .multidot.xTiO.sub.2. Said substrate also contains at least one member selected from the group consisting of manganese, cobalt, nickel, chromium, vanadium, niobium, tantalum, lanthanum and cerium ions in total amounts of 0.025 to 0.4% by weight. The capacitor according to the present invention excels, in the temperature independency of the capacitance and tan .delta., etc.

Abstract: Dielectricpowder compositions of magnesium titanate plus a glass, useful for forming dielectric layers in multilayer electrode/dielectric structures on an alumina substrate. Also, dispersions of such compositions in a vehicle and the resultant multilayer structures.

Abstract: A method for forming a cadmium-containing glass-reacted-ceramic body is described. This material is advantageously employed as the dielectric material in a capacitor. The method comprises mixing a barium-titanate alkaline-earth-metal-zirconate powder with glass powder, forming a cake or layer of the powder mix and firing the cake at from 1600.degree. to 2050.degree. F in a controlled cadmium containing atmosphere to sinter and densify the material. The cake is buried in an inert powder to which has been added a cadmium oxide powder to supply a source of cadmium external of the cake and to control the cadmium containing atmosphere during firing. Cadmium ions diffuse, during sintering, into the glass and further, into the ceramic grains to promote grain growth and to downwardly shift the Curie temperature.

Abstract: An integrally sintered ceramic complex which is suitable for use as a substrate of a surface acoustic wave device and can effectively reduce unnecessary ultrasonic waves.The method of manufacturing the integrally sintered ceramic complex is also disclosed.The disclosed ceramic complex comprises a first ceramic portion made of densely sintered piezoelectric ceramic material and a second ceramic portion made of porously sintered ceramic material. Both the ceramic portions are sintered integrally, and the second portion surrounds the first portion.The operating area of the surface acoustic wave device is formed on the surface of the first ceramic portion.

Abstract: An improved high dielectric constant ink useful in making thick film capacitors is disclosed in which a dielectric material is combined with a glass bonding agent having at least one electropositive element therein which is common with the powdered, high dielectric material which is one selected from the group consisting of chemically pure barium titanate and chemically pure barium titanate modified with from about 0.125% to about 5.0% by weight of a metal oxide additive. The glass bonding agent is an alkali-free binder comprising from 3 percent to 7 percent by total weight of the dielectric and binder materials.

Abstract: Sub-micron metal oxide powders, such as barium titanate, are prepared by mixing a carbohydrate material with solution of barium and titanium compounds, and in some instances other metal compounds, followed by ignition and calcining of the mixture to give sub-micron size particles of barium titanate loosely held together in friable aggregates. For economic reasons as well as their commercial availability, inorganic chlorides are suitable for use as one or more of the starting compounds. However, the presence of a chloride compound greatly influences the thermal stability of that compound in the mixture and hence its rate of decomposition was found to be slow. Accordingly, after the ignition step any chlorides present in the mixture are removed before calcination. The process provides a means for the direct formation of barium titanate free of unwanted phases and which is chemically pure. Barium titanate can also be prepared as an intimate mixture or as a solid solution with other oxides.

Abstract: A ceramic dielectric composition is provided which consists essentially of bismuth titanate with substituents, expressed by the formula:Bi.sub.4-x Me.sub.x Ti.sub.3-y R.sub.y O.sub.12where R is at least one divalent metal selected from strontium, barium and lead, Me is at least one pentavalent metal selected from tantalum, niobium and antimony, and both x and y are numbers falling within the range of 0.4 to 2.0 and the ratio of x/y is within the range of 0.9 to 1.1. This composition may contain specified metal oxide additives. The ceremic dielectric composition is sintered at a relatively low temperature, and exhibits a dielectric constant having a reduced dependence upon temperature variations over a wide use range, a reduced dielectric loss, enhanced resistivity and breakdown voltage.

Abstract: Finely divided dielectric powder compositions having the formula (Sr.sub.x Pb.sub.1-x TiO.sub.3).sub.a (PbMg.sub.0.5 W.sub.0.5 O.sub.3).sub.b whereinx is 0-0.10,a is 0.35-0.5,b is 0.5-0.65, anda plus b equals one,Said compositions having been calcined in air at 750.degree.-900.degree. C. for at least 5 minutes. These powder compositions may be formed into the desired shape and sintered in air at reduced temperatures to produce dielectric bodies of improved properties.

Abstract: A negative interseparator for use as a component in a separator system for alkaline rechargeable batteries comprises about 50% to 95% by weight of a titanate material such as potassium titanate, a matrix-forming fibrous material, and a thickening agent for use in forming the interseparator. The negative interseparator is interposed between the negative electrode and "main separator" in the aforementioned batteries.

Abstract: A ceramic dielectric material according to the present invention has a composition consisting essentially of La.sub.2 Ti.sub.2 O.sub.7, Sr.sub.2 Nb.sub.2 O.sub.7, and 1/2Mg.sub.2x --Ti.sub.2.sub.-2x O.sub.4.sub.-2x, where x lies in a range of 0 to 1.0. This material has a relatively large dielectric constant, a very stable temperature coefficient of the dielectric constant over a wide temperature range, a widely controllable value of the temperature coefficient of the dielectric constant, and a small dielectric loss. The temperature coefficient of the dielectric constant can be determined optionally in a wide range of value by simply changing the ratios among the three constituents of the composition.

Abstract: The cylinder and piston of an injection pump which are severely corroded by molten aluminum or the like are made of a composite sintered body containing two or more of the compounds selected from the group consisting of boron carbide, titanium diboride, zirconium diboride and boron nitride, and having excellent corrosion resistant, wear resistant and heat shock properties and high mechanical strength. One or more of the compounds selected from the group consisting of borides of tantalum, molybdenum and tungsten; carbides of silicon, zirconium, tantalum, vanadium,chromium, tungsten and molybdenum; nitrides of titanium, aluminum, silicon and zirconium; and oxides of aluminum and beryllium may be incorporated.

Abstract: A polishing composition suitable for polishing semi-conductive materials, e.g. silicon and germanium, comprises an aqueous slurry containing as a polishing agent a finely divided calcium-titanium-zirconium-oxygen product having the empirical formula CaTiZr.sub.3 O.sub.9. Additional materials that may be present include sodium hypochlorite, sodium metasilicate, potassium hydroxide, and glycerine.

Abstract: Very porous conductive ceramic substances constituted of diborides and a certain percentage of disilicides of metals in groups IVa, Va, VIa of the periodical classification of elements. Preparing of ceramic substances by sintering of fine powders and of grains of a mixture of diborides and disilicides of metals in groups IVa, Va, VIa in the periodic classification of elements in presence of a fluoride.

Abstract: A ceramic dielectric composition is provided including 30 to 94% by mol of SrTiO.sub.3, 1 to 22% by mol of Bi.sub.2 O.sub.3 and 5 to 69% by mol of TiO.sub.2, and further including 0.1 to 20% by weight of MgO with respect to the total weight of the above-mentioned three compounds SrTiO.sub.3, Bi.sub.2 O.sub.3 and TiO.sub.2, whereby the ceramic dielectric composition has a high dielectric constant and a low dielectric loss and further the variations of the dielectric constant and the dielectric loss with respect to the variation of an applied voltage, are respectively, very small.

Abstract: The invention relates to the production of inorganic fibers comprising a metal oxide phase and a finely divided disperse phase distributed throughout the oxide phase, the disperse phase constituting about 0.5 to 50% by weight of the fiber. The process involves preferably dry spinning a solution in water or an organic solvent of fiber forming components which, when heated to temperature of from 500.degree. to 1600.degree. C either in an inert or in a reactive atmosphere, form at least two phases with a miscibility gap, of which one phase is an oxide phase containing the other phase in very finely disperse form. Preferably, the solution contains a metal salt, the anion of which contains carbon so that upon heating there is formed an oxide phase comprising the oxide of said metal having carbon dispersed therein; if carbon is not in the anion, its precursor may be an organic compound, such as a polymer, present in the solution.

Abstract: For hydrostatically hot pressing bodies of borides, carbides or nitrides of titanium, zirconium or chromium from a powder having an excess of boron, carbon or nitrogen, the power is enclosed in a sealed container of a material which forms compounds with boron, carbon or nitrogen which have a melting point at least equal to that of the material of the container. Container materials may be for example metals from Group IVb of the Periodic System, particularly titanium and zirconium or their alloys in the case of titanium or chromium compounds and zirconium or zirconium base alloys in the case of zirconium compounds. This allows pressing at temperatures of up to 1700.degree.-1800.degree. C, which is high enough to cause bonding between the powder grains.

Abstract: A silicon nitride based ceramic is formed of silicon nitride and at least two metal oxides of such a type that when the metal oxides are heated separately they form a spinel. Combination of said metal oxides and said silicon nitride as fine powders and sintering same at a specified temperature for a specified period of time results in a silicon nitride based ceramic having improved mechanical and chemical properties.

Abstract: Method for adjusting index of refraction of optical coating by heat treating. PLZT ceramic can be sputtered to form a thin film optical coating material for various optical applications. The fact that its refractive index can be adjusted by diffusion makes it particularly useful for antireflection coating or reflection coating on optical surfaces.

Abstract: A ceramic material, which consists of lead zirconate with not greater than 20 atomic per cent of bismuth substituted for the lead, according to the formula Pb.sub.1.sub.-3x/2 Bi.sub.x ZrO.sub.3. Titanium to a concentration of not more than 50 atomic per cent can be substituted for the zirconium according to the formula Pb.sub.1.sub.-3x/2 Bi.sub.x Zr.sub.1.sub.-y Ti.sub.y O.sub.3. Potassium to a concentration of 2 to 20 atomic per cent can also be substituted for the lead in any of these materials, according to either the formula Pb.sub.1.sub.-3x/2.sub.-z/2 Bi.sub.x K.sub.z SrO.sub.3 or the formula Pb.sub.1.sub.-3x/2.sub.-z/2 Bi.sub.x K.sub.z Zr.sub.1.sub.-y Ti.sub.y O.sub.3. Uranium can also be included in any one of these ceramic materials to a concentration of not more than 10 atomic per cent. All of the ceramic materials can be produced by ceramic processes and sintering techniques.

Abstract: An improved reduction-reoxidation type semiconducting ceramic capacitor and the method for producing the same are disclosed. The main components of the substrate of the capacitor are CaTiO.sub.3, SrTiO.sub.3 and Bi.sub.2 O.sub.3.xTiO.sub.2. Said substrate also contains at least one member selected from the group consisting of manganese, cobalt, nickel, chromium, vanadium, niobium, tantalum, lanthanum and cerium ions in total amounts of 0.025 to 0.4% by weight. The capacitor according to the present invention excels, in the temperature independency of the capacitance and tan .delta., etc.