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4400427 |
Sintered silicon nitride ceramic articles having surface layers of controlled composition
Sintered silicon nitride-silica-yttria ceramic articles having silica-rich or yttria-rich casing layers are disclosed. The surface layers are formed by sintering pre-compacted bodies in a powder...
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4388414 |
Thermally stable silicon nitride material
A thermally stable, oxidation resistant ceramic Si 3 N 4 material is disclosed. The material has a substantially pure primary phase formed of substantially pure silicon nitride. A substantially...
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4386022 |
Voltage non-linear resistance ceramics
A voltage non-linear resistance ceramics having a larger voltage non-linear coefficient and a superior protection ability against the overvoltage is prepared by firing an essential component of...
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4384909 |
Bonding Si.sub.3 N.sub.4 ceramics
Compositions are disclosed for securing Si 3 N 4 parts together, these compositions being in the β'-Y 2 Si 2 O 7 --Y 3 Al 5 O 12 tetrahedron, e.g. compositions in mole % comprising (1) 15%...
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4383958 |
Method of producing dense silicon nitride ceramic articles having controlled surface layer composition
Dense, composite, polycrystalline ceramic articles comprising silicon nitride, silicon dioxide, and yttrium oxide and having thin surface layers of controlled composition are formed by sintering...
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4376742 |
Fugitive liquid phase densification of silicon nitride
Dense silicon nitride bodies are fabricated using conventional hot-pressing techniques using cerium oxide as a densification aid. The bodies are then further treated in a flowing inert atmosphere...
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4364859 |
Method for producing oxide powder
A method for the heat treatment of a radioactive substance by microwave power comprising preparing a nitrate solution of uranium, thorium, plutonium or a mixture thereof, and applying to the...
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4365011 |
Process for preparing pieces composed of solid electrolyte based on stabilized zircon and to pieces obtained by this process
The invention relates to a process for preparing pieces of solid electrolyte based on stabilized zircon having an improved conductivity due to the addition of Al 2 O 3 . According to the process,...
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4360598 |
Zirconia ceramics and a method of producing the same
Zirconia ceramics consisting mainly of ZrO 2 and Y 2 O 3 in a molar ratio of Y 2 O 3 /ZrO 2 of 2/98.about.7/93 and consisting of crystal grains having a mixed phase consisting essentially of...
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4357426 |
Humidity sensitive ceramics
A humidity sensitive ceramics comprises a sintered body consisting essentially of a semiconductive compound oxide with a perovskite structure and a compound oxide, said semiconductive compound...
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4357427 |
Economic preparation of alumina suitable for isostatic pressing and sintering
Method for preparing finely divided high purity alumina doped with a small predetermined percentage of magnesia. In the preparation, there is first formed a mixed clear solution of aluminum...
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4356272 |
Sintered bodies Al.sub.2 O.sub.3 -TiC-TiO.sub.2 continuing yttrium (y)
Sintered bodies having improved sinterability and toughness consist essentially of: (1) 100 parts by weight of titanium carbide, titanium oxide and aluminum oxide, the titanium carbide and titanium...
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4356136 |
Method of densifying an article formed of reaction bonded silicon nitride
A method of densifying an article formed of reaction bonded silicon nitride is disclosed. The reaction bonded silicon nitride article is packed in a packing mixture consisting of silicon nitride...
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4354964 |
Cermet materials
An electrically conducting cermet comprises a sintered compact of refractory oxide granules such as alumina granules having diameters of from 50 to 800 microns and a conductive network extending...
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4347167 |
Fine-grain semiconducting ceramic compositions
A semiconducting internal boundary layer ceramic composition having a fine grain structure suitable for use in thin-layer multilayer capacitors is made in one step by firing a mixture comprising a...
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4338403 |
Dielectric ceramics
A dielectric ceramic consisting essentially of at least 88 weight % of a main component and up to 12 weight % of stannic oxide (SnO 2 ), said main component consisting essentially of 34.5 to 82...
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4331627 |
Alumina sintered products and process for their production
A process for producing an alumina sintered product is disclosed wherein the starting alumina mixture contains about 0.01 to 0.55% by weight of MgO and 0.5 to 5.5% by weight of Y 2 O 3 . The...
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4330633 |
Solid electrolyte
A solid electrolyte having high electron conductivity and high oxide ion conductivity, which is composed of a sintered body consisting substantially of (a) an oxide of cobalt, (b) an oxide of at...
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4325710 |
Sintered ceramics for cutting tools and manufacturing process thereof
A sintered ceramics for cutting tools having a relative apparent density of not less than 98% is obtained by sintering a mixture substantially consisting of 80-95% by volume alumina and the balance...
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4323325 |
ethod of using Si.sub.3 N.sub.4.Y.sub.2 O.sub.3.SiO.sub.2 ceramic system for machine cast iron
A process for machine cutting of cast iron with a shaped tool which is a ceramic having as constituent ingredients about 4 to about 12% by weight Y 2 O 3 and a balance consisting essentially of...
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4322249 |
Process for the preparation of dispersion ceramics
In a process for the production of dispersion ceramics by sintering or hot pressing of a mixture of a matrix-forming ceramic material and of at least one ceramic embedment material dispersible...
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4310402 |
Gas tight sealant for zirconia sensors
In a high temperature gas measuring device consisting of a zirconia oxide solid electrolyte cell bonded to a support member, a sealant exhibiting a thermal coefficient of expansion comparable to...
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4309467 |
Composition for use in high-temperature hydrogen-fluorine environments and method for making the composition
The present invention relates to a composition particularly suitable for as structural components subject to high-temperature environments containing gaseous hydrogen and fluorine. The composition...
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4305848 |
Method of producing high conductive sinters
This application is directed to a method of manufacturing high conductive sinters of a conductive lanthanum, chromium composite oxide material in which the specific resistance is extremely reduced...
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4303447 |
Low temperature densification of zirconia ceramics
Addition of from about 1.0 to about 15% by weight of a vanadium oxide or boric oxide promoter to a zirconia (ZrO 2 ) powder promotes rapid densification at temperatures below about 1300° C. For...
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4302362 |
Stable pyrochlore resistor compositions
Thick film resistors, based on pyrochlore conductive phase, glass, and refractory fillers having a thermal expansion coefficient range of 40×10 -7 -60×10 -7 /° C. and low solubility in the...
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4296608 |
Cryogenic ceramic and apparatus
Ceramic material, and cryogenic refrigeration apparatus containing thermal energy absorbing elements made of the ceramic material, which is a dielectric insulator and has values of specific heat at...
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4293356 |
Method for adhesion of ceramics
A method for providing strong adhesion of two ceramic articles to each other or one ceramic article to an article of metallic copper, which method comprises applying, in the former adhesion, a...
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4292209 |
Ceramic component for MHD electrode
A ceramic component which exhibits electrical conductivity down to near room temperatures has the formula: Hf x In y A z O 2 where x=0.1 to 0.4, y=0.3 to 0.6, z=0.1 to 0.4 and A is a...
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4292081 |
Boride-based refractory bodies
The invention provides a novel class of sintered refractory and abrasive ies composed mainly of one or a combination of metal diborides such as titanium diboride TiB 2 , chromium diboride CrB 2 ,...
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4285732 |
Alumina ceramic
A particulate dispersion of α-alumina, magnesium oxide and an additive selected from the group consisting of zirconium oxide, hafnium oxide and mixtures thereof, is formed into a green body and...
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4284686 |
Spectacle lenses to reduce discomfort from aphakia and certain eye diseases
This invention is concerned with producing glasses suitable for use as spectacle lenses for aphakics or for persons subject to photoretinitis or retinitis pigmentosa. The glasses exhibit near-zero...
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4266978 |
Synthesis of mixed oxide composition
A non-aqueous gel of at least two metal oxides which is a precursor for glassy amorphous or crystalline mixed oxides is produced by reacting an alkoxide of one metal and a halide of another metal...
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4265666 |
Boron carbide La, Sr and/or Ba hexaboride ceramic material for a low temperature direct heating electric gun cathode
Ceramic material for a low temperature direct heating electron gun cathode, wherein it is constituted by a mixed ceramic material of a hexaboride of a refractory material consisting of at least one...
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4261753 |
Lanthanum-hexaboride carbon composition for use in corrosive hydrogen-fluorine environments
The present invention relates to a structural composition useful in corrosive hydrogen-fluorine environments at temperatures in excess of 1400° K. The composition is formed of a isostatically...
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4248440 |
Titania-alumina-yttria piston ring facing
Disclosed is a coating for bearing faces of piston rings and a powder composition for plasma spray application of such coating. The plasma spray powder comprises 94%-98% by weight of aluminum oxide...
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4244743 |
Sulfur containing refractory for resisting reactive molten metals
Improved refractories for resisting attack of molten titanium aluminum and similar metals are provided by the inclusion of sulfur. Metal, oxygen, and sulfur combinations, wherein sulfur is present...
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4229322 |
Ceramic component for electrodes
A ceramic component suitable for preparing MHD generator electrodes having the compositional formula: Y x (Mg y Cr z ) w Al (1-w) O 3 where x=0.9 to 1.05, y=0.02 to 0.2, z=0.8 to 1.05 and w=1.0...
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4225459 |
Glasses having a low non-linear refractive index for laser applications
Glass composition ranges are described which permit the introduction of laser activators into fluorphosphate glass with exceptionally high fluorine content while forming glasses of high...
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4222760 |
Preparation of oxynitride glass-ceramics
The instant invention is directed to the production of glass-ceramic articles from thermally crystallizable glass compositions containing, by weight, about 40-85% SiO 2 and 2.5-17% N as basic...
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4219359 |
Sintered body of zirconia for oxygen concentration sensor
A sintered body of zirconia material for an oxygen concentration sensor exhibiting an electromotive force in accordance with the difference in the concentration of oxygen between a gas tested and a...
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4216021 |
High strength silicon nitride sintered material
A high strength silicon nitride sintered material having a modulus of rupture of about 100 kg/mm 2 or more, which is prepared by sintering a mixture of about 88.7 to 98% by weight of silicon...
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4214666 |
Tubular discharge envelope composed of a polycrystalline transparent alumina and a high-pressure vapor discharge lamp using the same
A tubular discharge envelope and a high-pressure vapor discharge lamp using the same are disclosed. The envelope is composed of a polycrystalline transparent alumina having an average crystal grain...
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4211758 |
Ceramic compositions and articles prepared therefrom
A transparent or translucent article of manufacture such as a discharge tube for a metal vapor arc lamp is formed from a high density ceramic composition having a perovskite structure and having...
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4198244 |
Fluorescing agents for dental porcelain
A dental porcelain composition which includes, as fluorescing agents, 0.05 to 2% by weight of CeO 2 and 0.1 to 0.5% by weight of Tb 2 O 3 .
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4194917 |
Fired ceramic having dense and low thermal expansion characteristics
A fired ceramic having dense and low thermal expansion characteristics comprises 0.3 to 8 wt. % of at least one of rare earth oxides and has a thermal expansion coefficient of less than 0.3% and a...
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4191721 |
Making ceramic articles having a high degree of porosity and crushability characteristics
A method for increasing the porosity and crushability characteristics thereof embodies the firing of a ceramic compact comprising a reactant fugitive filler material and a ceramic material in a...
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4182972 |
Transparent polycrystalline alumina and high pressure vapor discharge lamp
A polycrystalline alumina has at least 50% unit surface area provided by crystals of at least 60 μm, and preferably 100 μm size. This improves the in-line transmission value and hence lamp...
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4181532 |
Production of colloidal dispersions
A colloidal dispersion is disclosed in which colloidal particles of an inorganic substance, and a compound of a Group IIA, or of a Group IIIA, or of a lanthanide (rare earth) element are dispersed...
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4179486 |
Method of protecting Si.sub.3 N.sub.4 ceramic alloy during heating
Articles made from Si 3 N 4 ceramic alloy powders are protected during heating by loosely packing them in Si 3 N 4 before heating. Compacts made from Si 3 N 4 ceramic alloys are protected...
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