Abstract: An insert may include a sintered silicon nitride including ?-Si3N4 as a main component. The area up to 0.5 mm deep from a surface of the sintered silicon nitride is a first region. The first region may include an oxygen content of less than 0.8% by mass. The first region may include ReMgSi2O5N (Re is at least one of Yb and Y). A cutting tool may include a holder that extends from a first end toward a second end and includes a pocket on a side of the first end, and the insert located at the pocket.

Abstract: A dielectric composition includes a main phase and segregation phases each including RE (at least one rare earth element). The main phase includes a main component having a perovskite crystal structure of ABO3 (A is one or more selected from Ba, Sr, and Ca, and B is one or more selected from Ti, Zr, and Hf). The segregation phases are classified into first segregation phases whose atomic ratio of Si to RE is 0 or more and 0.20 or less and second segregation phases whose atomic ratio of Si to the RE is more than 0.20. 0?S1/S2?0.10 is satisfied on a cross section of the dielectric composition, where S1 is an area ratio of the first segregation phases, and S2 is an area ratio of the second segregation phases. An atomic ratio of Si to RE in the second segregation phases is 0.80 or less on average.

Abstract: A structure includes: a ? silicon nitride crystal phase; and a Y2MgSi2O5N crystal phase. The structure gives a X-ray diffraction pattern by a ?-2? method, the pattern having a ratio of a peak intensity of a (22-1) plane of the Y2MgSi2O5N crystal phase to a peak intensity of a (200) plane of the ? silicon nitride crystal phase, the peak intensity of the (200) plane being determined at a position of 2?=27.0±1°, the peak intensity of the (22-1) plane being determined at a position of 2?=30.3±1°, and the ratio being 0.001 or more and 0.01 or less.

Abstract: A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m·K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/mm or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

Abstract: A ceramic material for radome is illustrated comprising: —about 80-95% (% wt) of Si3N4; about 5-15% (wt %) of magnesium aluminosilicates including 2.5-12.5% (wt %) of Si02, 0.5-3% (wt %) of MgO and 2-6% (wt %) of Al203; and having a density not lower than 2.5 g/cm3 and a dielectric constant not exceeding 6.5. A process for producing a radome is also illustrated.

Abstract: The invention concerns a sintered ceramic component of silicon nitride or sialon suitable as rolling element in a bearing and a manufacturing method for making such ceramic components. The ceramic component has high density and a homogeneous and fine microstructure, giving the component excellent mechanical properties. Manufacturing of the sintered ceramic component by SPS is cost-effective and rapid.

Abstract: A composite article having a body including a first phase that includes a nitride material, a second phase that includes a carbide material, and a third phase having one of an amorphous phase material with a nitrogen content of at least about 1.6 wt % or an amorphous phase material comprising carbon.

Abstract: A silicon nitride material is disclosed which has properties necessary for efficient operation of a corona discharge igniter system in an internal combustion gas engine allowing an increase in fuel efficiency of over 10%. The material is disclosed in a range of compositions, all of which exhibit high dielectric strengths, high mechanical strength, thermal shock resistance and fracture toughness, low dielectric constant and loss tangent and electrical resistivity, all of which significantly increase the efficiency of the igniter system over current state of the art alumina insulators. Moreover, the materials retain their dielectric strength and structural integrity at elevated temperatures, up to 800° C.-1000° C. One embodiment comprises a sintered silicon nitride process comprising powder batching, binder removal and sintering. In the preferred embodiment the method of manufacture for silicon nitride is an SRBSN process comprising powder batching, powder pressing, binder removal, nitriding and sintering.

Abstract: Silicon nitride materials with high strength, fracture toughness values, and Weibull moduli simultaneously, due to unique large grain reinforcing microstructures and well engineered grain boundary compositions. The invention demonstrates that, surprisingly and contrary to prior art, a silicon nitride material can be made which simultaneously has high strength above about 850-900 MPa, a Weibull above about 15 and high fracture toughness (above about 8 and 9 MPa·m1/2), and has reinforcing grains longer than 5 ?m, typically longer than 10 ?m in the microstructure without compromising its properties and reliability. The product of this invention can be processed using a variety of densification methods, including gas-pressure sintering, hot pressing, hot isostatic pressing, but is not limited to these, and does not require multiple heat treatments for all of these features to be achieved.

Abstract: A silicon nitride sintered body, wherein in a silicon nitride substrate consisting of crystal grains of ?-type silicon nitride and a grain boundary phase containing at least one type of rare earth element (RE), magnesium (Mg) and silicon (Si), the grain boundary phase consists of an amorphous phase and a MgSiN2 crystal phase. The X-ray diffraction peak intensity of any crystal plane of a crystal phase containing the rare earth element (RE) is less than 0.0005 times the sum of the diffraction peak intensities of (110), (200), (101), (210), (201), (310), (320) and (002) of the crystal grains of the ?-type silicon nitride; and the X-ray diffraction peak intensity of (121) of the MgSiN2 crystal phase is 0.0005 to 0.003 times the sum of the X-ray diffraction peak intensities of (110), (200), (101), (210), (201), (310), (320) and (002) of the crystal grains of the ?-type silicon nitride.

Abstract: A silicon nitride cutting tool comprising a sintered product is disclosed. The sintered product comprises silicon nitride, at least one rare earth element compound, and a magnesium compound. The silicon nitride cutting tool further comprises a surface region and an inside region comprising the sintered product with varying content ratios of component compounds to provide enhanced wear and fracture resistance.

Abstract: An insert includes a silicon nitride sintered body including ?-Si3N4 as a main component, Mg, and a rare-earth element Re (Y, La, Ce, Er, Dy, Yb). A content of Mg in terms of MgO is 1.0-7.0 mol %, a content of Re in terms of an oxide thereof is 0.4-1.0 mol %, and a total content of Mg and Re is from 1.7 to less than 7.5 mol %. The insert has a graded composition in which oxygen content increases from a surface of the sintered body toward an inside thereof such that 0.8-1.5 mass % of oxygen is contained in a region of less than 0.5 mm inside from the surface, 1.1-2.3 mass % of oxygen is contained in a region of 0.5 mm or more inside from the surface, and a difference in oxygen content between the regions is 0.1-1.0 mass %.

Abstract: A wear resistant member formed of silicon nitride sintered body having a volume of 4000 mm3 or more, the silicon nitride sintered body containing 1 to 5 mass % of a rare earth component in terms of rare earth element, 1 to 6 mass % of an Al component in terms of Al element, 10 to 3500 ppm of an Fe component in terms of Fe element, and 10 to 1000 ppm of a Ca component in terms of Ca element, wherein a ?-phase ratio of silicon nitride crystal grains is 95% or more, a maximum longer diameter of the silicon nitride crystal grains is 40 ?m or less, and each of dispersions in Vickers hardness and fracture toughness of an inner portion of the wear resistant member is within a range of ±10%. According to this structure, the wear resistant member can be manufactured with a low cost, and there can be provided a wear resistant member comprising a silicon nitride sintered body excellent in reliability and the dispersion in characteristics is effectively suppressed.

Abstract: Silicon nitride materials with high strength, fracture toughness values, and Weibull moduli simultaneously, due to unique large grain reinforcing microstructures and well engineered grain boundary compositions. The invention demonstrates that, surprisingly and contrary to prior art, a silicon nitride material can be made which simultaneously has high strength above about 850-900 MPa, a Weibull above about 15 and high fracture toughness (above about 8 and 9 MPa·m1/2), and has reinforcing grains longer than 5 ?m, typically longer than 10 ?m in the microstructure without compromising its properties and reliability. The product of this invention can be processed using a variety of densification methods, including gas-pressure sintering, hot pressing, hot isostatic pressing, but is not limited to these, and does not require multiple heat treatments for all of these features to be achieved.

Abstract: Provided are a silicon nitride substrate made of a silicon nitride sintered body that is high in strength and thermal conductivity, a method of producing the silicon nitride substrate, and a silicon nitride circuit substrate and a semiconductor module that use the silicon nitride substrate. According to the silicon nitride sintered body, in a silicon nitride substrate consisting of crystal grains 11 of ?-type silicon nitride and a grain boundary phase containing at least one type of rare earth element (RE), magnesium (Mg) and silicon (Si), the grain boundary phase consists of an amorphous phase 12 and a MgSiN2 crystal phase 13; the X-ray diffraction peak intensity of any crystal plane of a crystal phase containing the rare earth element (RE) is less than 0.0005 times the sum of the diffraction peak intensities of (110), (200), (101), (210), (201), (310), (320) and (002) of the crystal grains of the ?-type silicon nitride; and the X-ray diffraction peak intensity of (121) of the MgSiN2 crystal phase 13 is 0.

Abstract: A high-strength, fracture-resistant silicon nitride ceramic material that includes about 5 to about 75 wt-% of elongated reinforcing grains of beta-silicon nitride, about 20 to about 95 wt-% of fine grains of beta-silicon nitride, wherein the fine grains have a major axis of less than about 1 micron; and about 1 to about 15 wt-% of an amorphous intergranular phase comprising Si, N, O, a rare earth element and a secondary densification element. The elongated reinforcing grains have an aspect ratio of 2:1 or greater and a major axis measuring about 1 micron or greater. The elongated reinforcing grains are essentially isotropically oriented within the ceramic microstructure. The silicon nitride ceramic exhibits a room temperature flexure strength of 1,000 MPa or greater and a fracture toughness of 9 MPa-m(1/2) or greater. The silicon nitride ceramic exhibits a peak strength of 800 MPa or greater at 1200 degrees C.

Abstract: High-volume, fully dense, multi-component monoliths with microstructurally indistinguishable joints that can be used as refractory, corrosion and wear resistant components in the non-ferrous metal industry. The Si3N4 monoliths according to the invention comprise at least 90% by weight ?-type Si3N4 and up to 10% by weight of a predominantly amorphous binder phase, said binder phase being formed from compositions of the rare earth metal —Al—Si—O—N, rare earth metal —Mg—Si—O—N or Mg—Si—O—N systems. Preferably the rare earth metal is yttrium (Y). The monoliths have a volume of greater than 250 cm3. A method of making the multi-component monoliths is achieved by simultaneously joining and uniaxially hot pressing an assembly of reaction bonded silicon nitride bodies (RBSN bodies). RBSN bodies are placed in contact with each other in the substantial absence of any interlayer or ceramic paste in between.

Abstract: A sintered product of silicon nitride includes a crystal phase mainly having silicon nitride crystal grains and an amorphous grain-boundary phase located on the grain boundaries of the silicon nitride crystal grains. The grain-boundary phase contains lanthanum, aluminum, magnesium, silicon, and oxygen. The sintered product described above contains 0.1% by mass or more of lanthanum on an oxide basis, 0.05 to 0.6% by mass of aluminum on an oxide basis, 0.3% by mass or more of magnesium on an oxide basis, and 2.5% by mass or less of oxygen. The total amount of lanthanum on an oxide basis, aluminum on an oxide basis, and magnesium on an oxide basis is 3.5% by mass or less.

Abstract: A refractory composition having excellent erosion resistance and infiltration resistance to a molten metal and a formed article and a sintered article produced from the refractory composition are provided. The refractory composition comprises for 100 parts by mass of at least one compound selected from the group consisting of silicon nitride, boron nitride, and silicon carbide, 5 to 40 parts by mass of at least one compound selected from the group consisting of calcium fluoride, magnesium fluoride, calcium oxide or its precursor, magnesium oxide or its precursor, barium oxide or its precursor, and barium sulfate. The content of the silicon nitride, boron nitride, and silicon carbide in the composition is 20 mass % or more.

Abstract: An insert includes a silicon nitride sintered body including ?-Si3N4 as a main component, Mg, and a rare-earth element Re (Y, La, Ce, Er, Dy, Yb). A content of Mg in terms of MgO is 1.0-7.0 mol %, a content of Re in terms of an oxide thereof is 0.4-1.0 mol %, and a total content of Mg and Re is from 1.7 to less than 7.5 mol %. The insert has a graded composition in which oxygen content increases from a surface of the sintered body toward an inside thereof such that 0.8-1.5 mass % of oxygen is contained in a region of less than 0.5 mm inside from the surface, 1.1-2.3 mass % of oxygen is contained in a region of 0.5 mm or more inside from the surface, and a difference in oxygen content between the regions is 0.1-1.0 mass %.

Abstract: A composition and method for fabricating high-density Ta—Al—O, Ta—Si—N, and W—Si—N sputtering targets, having particular usefulness for the sputtering of heater layers for ink jet printers. Compositions in accordance with the invention comprise a metal component, Si3N4, and a sintering aid so that the targets will successfully sputter without cracking, etc. The components are combined in powder form and pressure consolidated under heated conditions for a time sufficient to form a consolidated blend having an actual density of greater that about 95% of the theoretical density. The consolidated blend may then be machined so as to provide the final desired target shape.

Abstract: To provide a sintered silicon nitride with conductivity and densification, an oxide of titanium group elements, such as titanium oxide, hafnium oxide, zirconium oxide and the like, aluminum oxide and/or aluminum nitride is added as needed to silicon nitride-oxidant of rare-earth elements-aluminum oxide system or silicon nitride-oxide of rare-earth elements-magnesia system, and then specified quantity of carbon nonotube (CNT) is added to the above mixture. CNT generates silicon carbide after the reaction with contiguous or proximal silicon nitride and the like depending on the sintering duration at high temperature. Since silicon carbide is generated along with nanotubes, the silicon carbide functions as conductor with excellent heat resistance, corrosion resistance and the like.

Abstract: A silicon nitride abrasion resistant member is formed of silicon nitride sintered body containing 2% to 4% by mass of a rare earth element in terms of oxide thereof as a sintering aid, 2% to 6% by mass of an Al component in terms of oxide thereof, and 2% to 7% by mass of silicon carbide. The silicon nitride sintered body has a porosity of 1% or less, a three-point bending strength of 800 to 1000 MPa, and a fracture toughness of 5.7 to 6.5 MPa·m1/2. According to this structure, even when an inexpensive silicon nitride powder manufactured by metal nitriding method is used, there can be provided a silicon nitride abrasion resistant member having a mechanical strength, high abrasion resistance, and a rolling life, equal to or higher than those of conventional silicon nitride sintered bodies, and excellent workability, and a method for manufacturing the member can be provided.

Abstract: A nitride glass with the general formula ?x?y?z is provided wherein ? is a glass modifier comprising at least one electropositive element. ? comprises Si, B, Ge, a and/or Al. ? is N or N together with O, whereby the atomic ratio of O:N is in the interval from 65:35 to 0:100.

Abstract: High-volume, fully dense, multi-component monoliths with microstructurally indistinguishable joints that can be used as refractory, corrosion and wear resistant components in the non-ferrous metal industry. The Si3N4 monoliths according to the invention comprise at least 90% by weight ?-type Si3N4 and up to 10% by weight of a predominantly amorphous binder phase, said binder phase being formed from compositions of the rare earth metal —Al—Si—O—N, rare earth metal —Mg—Si—O—N or Mg—Si—O—N systems. Preferably the rare earth metal is yttrium (Y). The monoliths have a volume of greater than 250 cm3. A method of making the multi-component monoliths is achieved by simultaneously joining and uniaxially hot pressing an assembly of reaction bonded silicon nitride bodies (RBSN bodies). RBSN bodies are placed in contact with each other in the substantial absence of any interlayer or ceramic paste in between.

Abstract: A sintered product of silicon nitride includes a crystal phase mainly having silicon nitride crystal grains and an amorphous grain-boundary phase located on the grain boundaries of the silicon nitride crystal grains. The grain-boundary phase contains lanthanum, aluminum, magnesium, silicon, and oxygen. The sintered product described above contains 0.1% by mass or more of lanthanum on an oxide basis, 0.05 to 0.6% by mass of aluminum on an oxide basis, 0.3% by mass or more of magnesium on an oxide basis, and 2.5% by mass or less of oxygen. The total amount of lanthanum on an oxide basis, aluminum on an oxide basis, and magnesium on an oxide basis is 3.5% by mass or less.

Abstract: A process for making a sintered ceramic medical device, comprising providing an unsintered ceramic composition, forming the unsintered ceramic composition into a green body that comprises unsintered ceramic, irradiating the green body with microwave radiation, and cooling the sintered body. The microwave radiation has a frequency capable of heating the unsintered ceramic to a temperature sufficient to sinter the green body, thereby preparing a sintered ceramic medical device. A medical device comprising volumetrically sintered ceramic, and a volumetrically sintered ceramic are also disclosed.

Abstract: A sintered ceramic material comprises a crystalline phase and an intergranular phase comprising a glass phase. The material is manufactured from a starting powder being mixed with an additive comprising one or more metal from a group of Li, Na, Mg, Ca, Sr, Ba, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Th, Pa or U. The additive is in non oxide form, or in a form which transforms to a metal or nitride during a synthesis in nitrogen atmosphere and the resulting glass phase having a high nitrogen content with a N:O ratio higher than 35:65 and a glass transition temperature above 950° C.

Abstract: In hexaboride particles having particles of a hexaboride of at least one element (X) selected from Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sr and Ca, or a dispersion of such particles, the surfaces of the hexaboride particles have physically been coated with a surface treatment agent containing silicon, selected from a silazane type treatment agent, a chlorosilane type treatment agent, an inorganic treatment agent having at least one alkoxyl group in the molecular structure, and an organic treatment agent having at least one alkoxyl group at a molecular terminal or in the side chain, or have been coated with the surface treatment agent, having chemically combined with hexaboride particles on the surfaces of the hexaboride particles.

Abstract: A silicon nitride sintered body exhibiting a high heat conductivity, the silicon nitride sintered body includes a rare earth element in an amount of 2 to 17.5 mass % in terms of the oxide thereof, Fe in an amount of 0.07 to 0.5 mass % in terms of the oxide thereof, Ca in an amount of 0.07 to 0.5 mass % in terms of the oxide thereof, Al in an amount of 0.1 to 0.6 mass % in terms of the oxide thereof, Mg in an amount of 0.3 to 4 mass % in terms of the oxide thereof, and Hf in an amount not larger than 5 mass % (including 0 mass %) in terms of the oxide thereof.

Abstract: A silicon nitride based ceramic, that is highly effective for use as a cutting tool for the high speed machining of cast irons, that is essentially a homogeneous mixture consisting of both crystalline and whisker forms of beta silicon nitride that are interstitially bonded by a stoichiometrically balanced glass mixture of magnesia, silica, yttria and zirconia, where the ratios of each have been controlled to increase the eutectic point and refractoriness of the mixed glass.

Abstract: The present invention provides a wear resistant member composed of silicon nitride sintered body containing 2–10 mass % of rare earth element in terms of oxide thereof as sintering agent, 2–7 mass % of MgAl2O4 spinel, 1–10 mass % of silicon carbide, and 5 mass % or less of at least one element selected from the group consisting of Ti, Zr, Hf, W, Mo, Ta, Nb and Cr in terms of oxide thereof, wherein a porosity of said silicon nitride sintered body is 1 vol. % or less, a three-point bending strength is 900 MPa or more, and a fracture toughness is 6.3 MPa·m1/2 or more. According to the above structure of the present invention, there can be provided a silicon nitride wear resistant member and a method of manufacturing the member having a high strength and a toughness property, and particularly excellent in rolling and sliding characteristics.

Abstract: A silicon nitride porous body (5) obtained by nitriding a molded body having metallic silicon (3) as a main component, the porous body having a porous structure with an average pore diameter of 3 ?m or above, and wherein the total content of silicon and nitrogen is 95% or above and the nitridation ratio of silicon is 90% or above. The silicon nitride porous body has a porous structure with a large average pore diameter, with a test specimen cut out from the porous body exhibiting large thermal conductivity and a small thermal expansion coefficient, and can be suitably used in a component for purifying gas and/or solution such as a ceramic filter.

Abstract: Sintered silicon nitride and a silicon nitride tool. The mean major axis length, the mean minor axis length, and the aspect ratio, represented by (mean major axis length/mean minor axis length) of constituent sintered silicon nitride grains in a silicon nitride tool are controlled, and the thermal conductivity and/or fracture toughness Kc thereof are enhanced, thereby providing a tool having a cutting edge which is not prone to chipping.

Abstract: A silicon nitride porous body which is obtained by nitriding a molded body having metallic silicon as a main component and by performing a high temperature heating treatment at a temperature higher than the nitriding temperature, and which has a porous structure with an average pore diameter of 3 ?m or above, and contains at least one kind of element selected from the group consisting of the groups 2A, 3A, 3B inclusive of lanthanoid elements, and 4B. The silicon nitride porous body has a porous structure with a large average pore diameter, a test specimen cut out from the porous body exhibiting a high thermal conductivity and a small thermal expansion coefficient, and can be suitably used in a component for purifying gas and/or solution such as a ceramic filter.

Abstract: The object of the present invention is to provide a ceramic body that can support a required amount of a catalyst component, without lowering the characteristics such as strength, being manufactured without forming a coating layer and providing a high performance ceramic catalyst that is excellent in practical utility and durability. A noble metal catalyst is supported directly on the surface of the ceramic body and the second component, consisting of compound or composite compound of element having d or f orbit in the electron orbits thereof such as W, Co, Ti, Fe, Ga and Nb, is dispersed in the first component made of cordierite or the like that constitutes the substrate ceramic. The noble metal catalyst can be directly supported by bonding strength generated by sharing the d or f orbits of the second component, or through interaction with the dangling bond that is generated in the interface between the first component and the second component.

Abstract: The present invention provides a silicon nitride wear resistant member composed of silicon nitride sintered body containing 1-10 mass % of rare earth element in terms of oxide thereof as sintering agent, wherein a total oxygen content of the silicon nitride sintered body is 6 mass % or less, a porosity of the silicon nitride sintered body is 0.5 vol. % or less, and a maximum size of pore existing in grain boundary phase of the silicon nitride sintered body is 0.3 &mgr;m or less. According to the above structure of the present invention, there can be provided a silicon nitride wear resistant member and a method of manufacturing the member having a high strength and a toughness property, and particularly excellent in sliding characteristics.

Abstract: A corrosion-resistive member is provided, including a corrosion-resistive face that is exposed to a corrosive gas causing ion bombardmemt. At least a part of the corrosion-resistive member is composed of a sintered silicon nitride body having an open porosity of not more than 5%. The sintered silicon nitride body constitutes the corrosion-resistive face, and if two auxiliary planes are formed by cutting the corrosion-resistive member to intersect vertically with the corrosion-resistive face and to be located vertically with respect to each other, the orientation index between the two auxiliary planes is in a range of 0.8 to 1.2, and the orientation index between the corrosion-resistive face and each of the auxiliary faces is at least 1.5.

Abstract: Sintered silicon nitride containing silicon nitride substantially as a primary component and containing substantially no Al2O3. The sintered silicon nitride further contains at least one element selected from among a Group 4 element of the periodic table, a rare earth element and Mg. The amount of the selected element as converted to its oxide is at least 0.5 mol % and less than 2.6 mol % based on the entirety of the sintered silicon nitride. Also disclosed is a cutting tip, a wear-resistant member, a cutting tool and a method for producing the sintered silicon nitride.

Abstract: Corrosion-resistive ceramic materials include a silicon based ceramic, wherein a percentage of respective metal elements other than metal elements constituting sintering agents and silicon is not more than 10 weight ppm. The corrosion-resistive ceramic materials show a high corrosion resistance with respect to corrosive substances and suppress particle generation due to an exposure to corrosive substances. Therefore, chippings and cracks do not occur easily during machining work.

Abstract: A Si3N4 composite substrate which manifests no generation of cracking on the substrate even by mechanical shock or thermal shock, and is excellent in heat radiation property and heat-cycle-resistance property is obtained by using a Si3N4 substrate as a ceramic substrate. A Si3N4 substrate having a thermal conductivity of 90 W/m·K or more and a three-point flexural strength of 700 MPa or more is used, and the thickness tm of a metal layer connected on one major surface of the substrate and the thickness tc of the Si3N4 substrate are controlled so as to satisfy the relation formula: 2 tm≦tc≦20 tm. When metal layers are connected to both major surfaces of the Si3N4 substrate, the thickness tc and the total thickness ttm of the metal layers on both major surfaces are controlled so as to satisfy the relation formula: ttm≦tc≦10 ttm.

Abstract: Metal oxides particularly useful for the manufacture of catalytic membranes for gas-phase oxygen separation processes having the formula: AxA′x′A″2-(x+x′)ByFey′B″2-(y+y′)O5+z where: x and x′ are greater than 0; y and y′ are greater than 0; x+x′ is equal to 2; y+y′ is less than or equal to 2; z is a number that makes the metal oxide charge neutral; A is an element selected from the lanthanide elements; A′ is an element selected from Be, Mg, Ca, Sr, Ba and Ra; A″ is an element selected from the f block lanthanides, Be, Mg, Ca, Sr, Ba and Ra; B is an element selected from the group consisting of Al, Ga, In or mixtures thereof and B″ is Co or Mg, with the exception that when B″ is Mg, A′ and A″ are not Mg. The metal oxides are useful for preparation of dense membranes which may be formed from dense thin films of the mixed metal oxide on a porous metal oxide element.

Abstract: A low-thermal-expansion, rigid and wear-resistant ceramic is provided.

Abstract: Sintered silicon nitride and a silicon nitride tool. The mean major axis length, the mean minor axis length, and the aspect ratio, represented by (mean major axis length/mean minor axis length) of constituent sintered silicon nitride grains in a silicon nitride tool are controlled, and the thermal conductivity and/or fracture toughness Kc thereof are enhanced, thereby providing a tool having a cutting edge which is not prone to chipping.

Abstract: A sensor material for measuring physical parameters capable of configuring a sensor capable of directly measuring a high value of physical parameters such as high stress or high pressure without employing a pressure resistance container. The sensor material for measuring static and dynamic physical parameters includes a matrix made of an electrically insulating ceramic material, and piezoresistance materials which are dispersed in the matrix so as to be electrically continuous to each other.

Abstract: A dry refractory composition having superior insulating value. The dry refractory composition also may have excellent resistance to molten metals and slags. The composition includes filler lightweight material, which may be selected from perlite, vermiculite, expanded shale, expanded fireclay, expanded alumina silica hollow spheres, bubble alumina, sintered porous alumina, alumina spinel insulating aggregate, calcium alumina insulating aggregate, expanded mulllite, cordierite, and anorthite, and matrix material, which may be selected from calcined alumina, fused alumina, sintered magnesia, fused magnesia, silica fume, fused silica, silicon carbide, boron carbide, titanium diboride, zirconium boride, boron nitride, aluminum nitride, silicon nitride, Sialon, titanium oxide, barium sulfate, zircon, a sillimanite group mineral, pyrophyllite, fireclay, carbon, and calcium fluoride.

Abstract: A ceramic material which is an orthorhombic boride of the general formula: AlMgB14:X, with X being a doping agent. The ceramic is a superabrasive, and in most instances provides a hardness of 40 GPa or greater.

Abstract: A slurry Si-base composition comprising an Si powder having a thickness of a surface oxide film ranging from 1.5 to 15 nm, 50 to 90% by weight of water, 0.2 to 7.5% by weight, in terms of oxide, of a sintering aid and 0.05 to 3% by weight of a dispersant, the Si-base composition having a pH value adjusted to 8-12. This slurry Si-base composition is produced by a process which comprises subjecting Si powder to oxidation treatment at 200 to 800° C. in air, adding 50 to 90% by weight of water, 0.2 to 7.5% by weight, in terms of oxide, of a sintering aid and 0.05 to 3% by weight of a dispersant to the oxidized Si powder and performing such a pH adjustment that the resultant mixture has a pH value of 8 to 12. The slurry Si-base composition not only enables producing a ceramic of Si3N4 at a lowered cost without the need to install explosionproof facilities but also allows the obtained Si3N4 ceramic having a relative density of at least 96% and a flexural strength of at least 800 MPa can be obtained.

Abstract: A sintered Si3N4 material, valves and components made with the material, and methods for making same.

Abstract: A method of producing the silicon nitride sintered body includes the steps of forming a compact of molding materials including silicon nitride powder, a Mg component and a sintering aid, and sintering the molding materials at 1,800 to 2,000° C. under a nitrogen atmosphere. The materials at least include an oxide of Mg in a range of 0.3 to 10 wt. %. A constant temperature is kept for at least 0.5 hours in a temperature range of 1,400 to 1,700° C. before the temperature is increased to the sintering temperature. A silicon nitride body having high thermal conductivity and excellent electrical insulation properties at high temperature can thus be provided.