Abstract: A member for hydrogen production includes a ceramic composite in which a plurality of ceramic particles having an average particle diameter ranging from 5 nm to 200 nm are dispersed in a porous insulator having a different component from the ceramic particles. The ceramic particles comprise at least one substance selected from the group consisting of AXO3±? (where 0???1, A: at least one of rare earth elements, alkaline earth elements, and alkali metal elements, X: at least one of transition metal elements and metalloid elements, and O: oxygen), cerium oxide, and zirconium oxide as a main component.

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 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/rum 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 sintered compact contains cubic sialon, ?-sialon, and at least one of a first component and a second component. The first component is at least one element selected from the group consisting of iron, cobalt, nickel, and group 4 elements, group 5 elements, and group 6 elements of the periodic table. The second component is at least one compound containing at least one element selected from the group consisting of group 4 elements, group 5 elements, and group 6 elements and at least one element selected from the group consisting of carbon, nitrogen, and boron.

Abstract: The present invention relates to a method of manufacturing a porous pre-sintered granule for a sintered reaction-bonded silicon nitride, to which a pressure forming technology can be applied to obtain a porous sintered reaction-bonded silicon nitride having high porosity and having a structure in which macropores and micropores coexist with each other, and to a porous pre-sintered granule manufactured by the method. The method includes the steps of: granulating a raw material comprising silicon and sintering additives including yttrium, aluminum and at least one alkali earth metal compound; and pre-sintering the granulated raw material at a temperature of 1300˜1375° C. under an inert atmosphere. According to the present invention, a porous pre-sintered granule for porous sintered reaction-bonded silicon nitride, which can increase the air permeability and trapping efficiency by controlling the size of a pore channel such that macropores and micropores coexist, can be manufactured.

Abstract: A silicon nitride material is disclosed which has properties beneficial for efficient operation of a corona discharge igniter system in an internal combustion gas engine.

Abstract: A ceramic sintered body according to the present invention comprises: silicon carbide and aluminum nitride, wherein a weight ratio of the aluminum nitride relative to a total weight ratio of the silicon carbide and the aluminum nitride is greater than 10% and 97% or smaller, and a bulk density is greater than 3.18 g/cm3.

Abstract: Methods for improving the antibacterial characteristics of a biomedical implant. In some implementations, the method may comprise providing a biomedical implant material block. The biomedical implant material block may comprise a silicon nitride ceramic material. The surface chemistry of the biomedical implant material block may be altered to improve the antibacterial characteristics of the biomedical implant material block. In some implementations, the surface chemistry may be altered by firing the biomedical implant material block in a nitrogen-rich environment or otherwise increasing the nitrogen content in the transitional oxide layer of at least a portion of the biomedical implant material block. The surface of the biomedical implant material block may also, or alternatively, be roughened to improve antibacterial characteristics of the implant.

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: A duplex eutectic silicon alloy including 30-70 weight % silicon, 10-45 weight % nitrogen, 1-40 weight % aluminum, and 1-40 weight % oxygen has a eutectic structure comprising a ??-sialon phase and an ??-sialon phase. The alloy is produced by controlling cooling at a rate of 50° C. or less per minute in combustion synthesis. A ductile sintered product capable of replacing steel in various applications can be produced by placing a compact composed of a powder of the alloy in a sintering furnace which can supply a heat quantity at least ten times the heat capacity of the compact; and sintering the compact at a pressure at least as great as atmospheric pressure, within a nitrogen atmosphere in which the silicon gas mole fraction is 10% or more, and at a temperature within the range from 1400° C. to 1700° C.

Abstract: In a method for producing jewelry articles, forming a predetermined shape from a plurality of sinterable materials, heating the plurality of sinterable materials to a first temperature and for a first time period sufficient to produce a substrate that retains the predetermined shape during manipulation, cooling the substrate to a second temperature at which the substrate is manipulable, manipulating the substrate to incorporate at least one design feature in the substrate, heating the substrate to a third temperature and for a second time period sufficient to sinter the substrate, and cooling the substrate to obtain the jewelry article.

Abstract: A deposition technique for forming an oxynitride film is provided. A highly reliable semiconductor element is manufactured with the use of the oxynitride film. The oxynitride film is formed with the use of a sputtering target including an oxynitride containing indium, gallium, and zinc, which is obtained by sintering a mixture of at least one of indium nitride, gallium nitride, and zinc nitride as a raw material and at least one of indium oxide, gallium oxide, and zinc oxide in a nitrogen atmosphere. In this manner, the oxynitride film can contain nitrogen at a necessary concentration. The oxynitride film can be used for a gate, a source electrode, a drain electrode, or the like of a transistor.

Abstract: The fluorescent substance according to the embodiment is generally represented by (M1?xECx)aSibAlOcNd, and is a kind of the Sr2Si7Al3ON13 phosphors. The substance is in the form of crystals having a mean grain size of 20 to 100 ?m, and the aspect ratio thereof is in the range of 2 to 4. This substance emits luminescence having a peak in the wavelength range of 580 to 660 nm when excited by light of 250 to 500 nm. The embodiment also provides a light-emitting device comprising this substance in combination with a light-emitting element and a green light-emitting fluorescent substance.

Abstract: A method and product made by using a polymeric ceramic precursor to synthesize dense, crack-free bulk ceramics in a technique using a sacrificial mold provides a ceramic structure for many technical, medical and industrial applications. The novel process uses an open cell material as a sacrificial mold to shape a ceramic precursor during curing. The cured ceramic green body can be machined and shaped to form the desired ceramic structure prior to final pyrolysis. The open cell material forms gas release paths to release large amount of gases generated during the pyrolysis of the cured ceramic precursor. After pyrolysis, an intact, dense, crack-free ceramic structure with high purity, strength and durability is obtained. Uses of the present invention include, but are not limited to, bulk ceramic parts, ceramic crucibles, a replacement material in some applications involving glass, silicon carbides, silicon nitrides, hafnium carbide and the like.

Abstract: A sintered material based on silicon carbide (SiC) reactively sintered between 1,100° C. and 1,700° C. to form a silicon nitride binder (Si3N4), intended in particular for fabricating an aluminum electrolysis cell, including 0.05% to 1.5% of boron, the Si3N4/SiC weight ratio being in the range 0.05 to 0.45.

Abstract: A sintered refractory block based on silicon carbide (SiC) with a silicon nitride (Si3N4) bond, for the manufacture of a aluminium electrolysis vessel, characterized in that it comprises, expressed in percentage by weight, at least 0.05% boron and/or between 0.05 and 1.2% calcium.

Abstract: A silicon nitride substrate having appropriately adjusted warpage and surface roughness can be obtained by mixing magnesium oxide of 3 to 4 wt % and at least one kind of rare-earth element oxide of 2 to 5 wt % with silicon nitride source material powder to form a sheet-molded body, sintering the sheet-molded body, and performing a heat treatment at a temperature of 1,550 to 1,700 degree C. with a pressure of 0.5 to 6.0 kPa with a plurality of substrates being stacked. Also, a silicon nitride circuit board and a semiconductor module using the same are provided.

Abstract: In the silicon nitride substrate concerning an embodiment of the invention, degree of in-plane orientation fa of ? type silicon nitride is 0.4-0.8. Here, degree of in-plane orientation fa can be determined by the rate of the diffracted X-ray intensity in each lattice plane orientation in ? type silicon nitride. As a result of research by the inventors, it turned out that both high fracture toughness and high thermal conductivity are acquired, when degree of in-plane orientation fa was 0.4-0.8. Along the thickness direction, both the fracture toughness of 6.0 MPa·m1/2 or higher and the thermal conductivity of 90 W/m·K or higher can be attained.

Abstract: A new composition and medical implant made there from comprises a thick diffusion hardened zone, and layered ceramic surface. Orthopedic implants comprising the new composition, methods of making the new composition, and methods of making orthopedic implants comprising the new composition are disclosed.

Abstract: The invention relates to a process for the production of a molded porous ceramic article containing ?-SiC, which process comprises the following steps: the preparation of a molded article containing silicon and carbon and the subsequent pyrolysis and siliconization of the article containing silicon and carbon to form SiC. The invention further relates to a molded porous ceramic article containing SiC which has been produced from a molded article containing silicon and carbon.

Abstract: A silicon nitride sintered material includes a silicon nitride crystal and a grain boundary layer that contains at least two of a first metal silicide (a metal silicide having, as a first metal element, at least one selected from the group consisting of Fe, Cr, Mn and Cu), a second metal silicide (a metal silicide having, as a second metal element, at least one of W or Mo) and a third metal silicide (a metal silicide having a plurality of metal elements including the first metal element and the second metal element), wherein the grain boundary layer has neighboring phase where at least two of the first through third metal silicides exist in contact with each other.

Abstract: The present invention provides methods for making a microporous ceramic material using a metal silicon powder and including a reaction sintering process of the silicon. A material for forming a microporous ceramic material used in these methods includes a metal silicon powder, a silicon nitride powder and/or a silicon carbide powder, and if desired, a yttrium oxide powder and/or an aluminum oxide powder. These methods can make a microporous ceramic material that can be used preferably as a gas or liquid filter, a catalyst carrier or a support of a gas separation membrane.

Abstract: The invention provides Al2O3 dispersion-strengthened Ti2AlN composites, wherein Ti2AlN matrix and Al2O3 strengthening phase both are reactively formed in situ. The volume fraction of Al2O3 is 5% to 50%; the particle size of Al2O3 ranges from 500 nm to 2 ?m, with the mean size of Al2O3 particles about 0.8 ?m to 1.2 ?m; the shape of Ti2AlN grain is plate-like about 80 nm to 120 nm thick and 0.5 ?m to 2 ?m long. The composites exhibit excellent deformability at high temperature under compression and flexure stresses, and possess excellent oxidation resistance at 1100° C. to 1350° C. for long time (100 h). The composites show typical metallic conductor behavior and the electrical resistivity at room temperature is 0.3 to 0.8 ??·m. The invention also provides a method for preparing the same: First, nanoparticles in Ti—Al binary system were prepared in continuous way by hydrogen plasma-metal reaction (HPMR) using Ti—Al alloy rods with Al content 20% to 60% by atom, or pure Al rods and pure Ti rods.

Abstract: A method for producing a silicon nitride filter, which comprises heat-treating in nitrogen a green body comprising from 60 to 95 mass % of metal silicon particles having an average particle diameter of from 10 to 75 ?m, wherein particles having particle diameters of from 5 to 100 ?m are at least 70 mass % in the entire metal silicon particles, and from 5 to 40 mass % of a pore-forming agent, to convert metal silicon substantially to silicon nitride. More preferably, the green body contains at least one member selected from the group consisting of an inorganic acid salt, an organic acid salt and a hydroxide containing at least one metal element selected from the group consisting of Mg, Ca, Fe and Cu.

Abstract: After an alloy powder including W, Cr, at least one of Ti, Zr, and Hf, and at least one of V, Nb, and Ta is produced, the alloy powder, a powdery carbon material, and a catalyst are heat-treated in the presence of a nitrogen gas. The alloy powder is carbonitrided into a multicomponent ceramics powder, and sintered into a sintered body. Alternatively, a powder of a first substance including at least two of Ti, Al, V, Nb, Zr, Hf, Mo, Ta, Cr, and W is molded into a molded body. Then, the surface of the molded body is surrounded by a second substance including a metal element which is not contained in the powder of the first substance, and the molded body is heat-treated in an atmosphere in which N is present. A porous sintered body thus produced is crushed into a multicomponent ceramics powder.

Abstract: A die comprises metal-rich sections which form an inner wall and an outer wall of the die, respectively. Gradient sections are disposed adjacent to the metal-rich sections, respectively. Further, a ceramics-rich section is disposed between the gradient sections. A punch comprises an inner ceramics-rich section, a gradient section, and an outer metal-rich section. In the die, the composition ratio of metal gradually decreases from the metal-rich sections to the ceramics-rich section. Similarly, in the punch, the composition ratio of the metal gradually decreases from the metal-rich section to the ceramics-rich section.

Abstract: A method for producing a silicon nitride honeycomb filter, which comprises heat-treating in a nitrogen atmosphere a green body comprising from 50 to 85 mass % of metal silicon particles having an average particle diameter of from 5 to 50 ?m, from 5 to 30 mass % of glass hollow particles having a softening temperature of from 400 to 1000° C. and from 10 to 20 mass % of an organic binder to convert metal silicon substantially to silicon nitride.

Abstract: A method for sealing a silicon nitride filter having a generally columnar outer shape and a plurality of through-holes mutually parallel to one another, extending between the opposing end surfaces, which comprises selectively packing a composition containing metal silicon particles in the vicinity of the opening of the through-holes to be sealed on each end surface, subjecting the silicon nitride filter to a heat treatment in a nitrogen atmosphere so that the metal silicon particles contained in the composition are nitrided and formed into silicon nitride for sealing.

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: A method for producing a silicon nitride filter including heat-treating in nitrogen a green body containing from 40 to 90% of metal silicon particles having an average particle diameter of from 1 to 200 ?m and from 10 to 60% of a pore-forming agent, where the total amount of the metal silicon particles and the pore-forming agent is at least 90%, forms a porous product made substantially of silicon nitride.

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 invention provides a process for the production of sialon ceramic (and a sialon ceramic produced by such a process) comprising or including the steps of: (I) preparing a sialon reactant mixture including or comprising: a) silicon metal; b) clay; and c) a secondary aluminium source; (II) heating the reactant mixture in an atmosphere containing nitrogen gas to a temperature sufficient to substantially react the silicon metal, the secondary aluminium source and the nitrogen with the clay to form or to contribute to the forming of the sialon product; wherein the clay participates in the reaction as a source of aluminium and silicon. Further, the invention provides a method for preparing a sialon ceramic in a predetermined shape.

Abstract: After an alloy powder including W, Cr, at least one of Ti, Zr, and Hf, and at least one of V, Nb, and Ta is produced, the alloy powder, a powdery carbon material, and a catalyst are heat-treated in the presence of a nitrogen gas. The alloy powder is carbonitrided into a multicomponent ceramics powder, and sintered into a sintered body. Alternatively, a powder of a first substance including at least two of Ti, Al, V, Nb, Zr, Hf, Mo, Ta, Cr, and W is molded into a molded body. Then, the surface of the molded body is surrounded by a second substance including a metal element which is not contained in the powder of the first substance, and the molded body is heat-treated in an atmosphere in which N is present. A porous sintered body thus produced is crushed into a multicomponent ceramics powder.

Abstract: A process for forming a silicon nitride-bonded silicon carbide honeycomb monolith by a) forming a plasticizable mixture which includes (1) about 60% to 85% by weight, powdered silicon carbide with a median particle size of about 10-40 micrometers; (2) about 15% to 40% by weight, powdered silicon metal with a median particle size of about 5-20 micrometers; and, (3) organic components; b) extruding the plasticizable mixture to form a green honeycomb monolith; c) drying the green honeycomb monolith; and, d) heating the honeycomb monolith to 1450° C. with a hold of 1 hour in an atmosphere of argon; and, e) nitriding the honeycomb monolith between 1450° C. to 1600° C. for a time sufficient to obtain a silicon nitride-bonded silicon carbide body.

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 &mgr;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: A silicon nitride sintered product comprising silicon nitride grains and a grain boundary phase, wherein the grain boundary phase consists essentially of a single phase of a Lu4Si2O7N2 crystal phase, and the composition of the silicon nitride sintered product is a composition in or around a triangle ABC having point A: Si3N4, point B: 28 mol % SiO2-72 mol % Lu2O3 and point C: 16 mol % SiO2-84 mol % Lu2O3, as three apexes, in a ternary system phase diagram of a Si3N4—SiO2—Lu2O3 system. Also disclosed is a silicon nitride sintered product comprising silicon nitride grains and a grain boundary phase of an oxynitride, wherein the composition of the sintered product is a composition in a triangle having point A: Si3N4, point B: 40 mol % SiO2-60 mol % Lu2O3 and point C: 60 mol % SiO2-40 mol % Lu2O3, as three apexes, in a ternary system phase diagram of a Si3N4—SiO2—Lu2O3 system.

Abstract: A process for forming a silicon nitride-bonded silicon carbide honeycomb monolith by a) forming a plasticizable mixture which includes (1) about 60% to 85% by weight, powdered silicon carbide with a median particle size of about 10-40 micrometers; (2) about 15% to 40% by weight, powdered silicon metal with a median particle size of about 5-20 micrometers; and, (3) organic components; b) extruding the plasticizable mixture to form a green honeycomb monolith; c) drying the green honeycomb monolith; and, d) heating the honeycomb monolith to 1450° C. with a hold of 1 hour in an atmosphere of argon; and, e) nitriding the honeycomb monolith between 1450° C. to 1600° C. for a time sufficient to obtain a silicon nitride-bonded silicon carbide body.

Abstract: The present invention provides a silicon nitride filter which is a filter excellent in heat resistance, thermal shock resistance, corrosion resistance, acid resistance and mechanical strength and suitable for dust arresting or dust removing, and which is particularly useful as a filer for particulates, and a method for its production.

Abstract: A method for sealing a silicon nitride filter having a generally columnar outer shape and a plurality of through-holes mutually parallel to one another, extending between the opposing end surfaces, which comprises selectively packing a composition containing metal silicon particles in the vicinity of the opening of the through-holes to be sealed on each end surface, subjecting the silicon nitride filter to a heat treatment in a nitrogen atmosphere so that the metal silicon particles contained in the composition are nitrided and formed into silicon nitride for sealing.

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 zirconia based article having a core of ZrO2 and/or partially reduced ZrO2, is characterized in that it includes, over at least part of its surface, a superficial layer integral with the article, the thickness of the superficial layer including a plurality of regions of which one external region is formed of zirconium nitride having a gold metallic appearance.

Abstract: A plasticizable raw material batch mixture for forming a silicon carbide honeycomb structure comprising the following components: (1) powdered silicon metal; (2) a carbon precursor comprising a water soluble crosslinking thermoset resin having a viscosity of less than about 1000 centipoise (cp), and preferably less than about 500 cp; (3) a powdered silicon-containing filler; and, (4) a water soluble thermoplastic binder. Optionally, the batch mixture can include either, or both, an organic fibrous filler and a pore-forming filler comprising either a graphitic or a thermoplastic pore-forming filler.

Abstract: An alumina-based composite sintered material comprising alumina as a main ingredient and containing one or more carbonitridation products of groups IVa, Va and VIa of the periodic table and/or two or more carbonitridation products of solid solutions of groups IVa, Va and VIa of the periodic table. The content of nitrogen solid solute in the carbonitridation product increases from the interior to the surface of the sintered material, and the Vickers hardness at the surface of the sintered material is 19.5 GPa or more.

Abstract: An Si3N4 sintered body produced by reactive sintering of silicon, wherein a compound of at least one element selected from the group consisting of Y, Yb and Sm is contained by 0.6 to 13% by weight as Ln2O3 (wherein Ln=Y, Yb or Sm), an oxygen content in Si3N4 crystal grains is not more than 1% by weight, a ratio of Si and Ln in the Si3N4 sintered body is within a range of 0.1 to 0.8 in a molar ratio of SiO2/Ln2O3 of the Si in terms of SiO2 to the oxide Ln2O3, and the sintered body has a relative density of 85 to 99.9%, a thermal conductivity of at least 70 W/m.K or more and a three-point bending strength of at least 600 MPa. The Si3N4 sintered body is produced by mixing 80 to 99% by weight of silicon powder and 1 to 20% by weight of powder of oxide of at least one element of Y, Yb and SM, by nitriding a molded body of the powder mixture in an atmosphere containing nitrogen at 1400° C.

Abstract: The invention concerns a process for manufacturing a part made of high temperature-resistant, ceramic material based on aluminum nitride and reaction sintering. The process comprises the steps of preparing a homogeneous mixture of boron nitride powder, aluminum powder and a paste-like binder, capable of solidifying by chemical reaction and by solvent loss through drying. The mixture is formed by mold casting and then pressed and heated, to a temperature not exceeding approximately 70° C., to harden the binder and to obtain a solid and manipulable unfired part. The binder is eliminated by heating to a temperature of approximately 300° C. Pores of the unfired part are impregnated by immersing the part in a bath of molten aluminum or aluminum alloy to form an impregnated preform. Thereafter, the impregnated preform is removed from the bath, cooled, and machined to the final dimensions of the part. A ceramic is obtained by reaction sintering the machined part at a temperature of 900 to 1000° C.

Abstract: A multi-layered heat distributor system is provided for use in a microwave process. The multi-layered heat distributors includes a first inner layer of a high thermal conductivity heat distributor material, a middle insulating layer and an optional third insulating outer layer. The multi-layered heat distributor system is placed around the ceramic composition or article to be processed and located in a microwave heating system. Sufficient microwave energy is applied to provide a high density, unflawed ceramic product.

Abstract: Molybdenum disilicide/&bgr;′-Si6-zAlzOzN8-z, wherein z=a number from greater than 0 to about 5, composites are made by use of in situ reactions among &agr;-silicon nitride, molybdenum disilicide, and aluminum. Molybdenum disilicide within a molybdenum disilicide/&bgr;′-Si6-zAlzOzN8-z eutectoid matrix is the resulting microstructure when the invention method is employed.

Abstract: There is disclosed a silicon nitride sintered body produced by sintering a molded article which comprises a mixture of a silicon nitride powder as the main component and plural kinds of sintering additives, wherein said silicon nitride powder is set to be 0.1 to 1.0 &mgr;m in average grain size, and said plural kinds of sintering additives includes first and second sintering additives, said first sintering additive comprising oxide powders of at least one element of Group 3a element, said second sintering additive comprising oxide powders of at least one element selected from Zr (zirconium), Hf (hafnium), Nb (niobium), Ta (tantalum) and W (tungsten), said first sintering additive having the average grain size set to be 0.1 to 10 times as large as the average grain size of said silicon nitride powder and being incorporated in an amount ranging from 0.

Abstract: This invention relates to a method of joining silicon nitride having on its surface a thin layer of active silicon metal to carbon steel, wherein the active silicon layer is formed through the thermal dissociation of silicon nitride(Si3N4) into silicon(Si) and nitrogen gas(N2). The active silicon layer is directly joined to carbon steel via an induced eutectic melting reaction between the silicon (Si) an iron (Fe) of carbon steel, or via brazing of two materials Ag—Cu alloys. This joining process does not require the use of expensive Ag—Cu—Ti active brazing alloys containing an active metal (Ti) or a sputtering method designed to coat the active metals on surface of silicon nitride.

Abstract: A high thermal conductive silicon nitride base sintered body which comprises a phase comprising crystal grains of silicon nitride and a grain boundary phase containing a compound of at least one element selected from the group consisting of yttrium and the lanthanide elements in an amount of 1 to 20% by weight in terms of oxide amount, and contains free silicon dispersed therein in an amount of 0.01 to 10% by weight based on the whole. This high thermal conductive silicon nitride base sintered body has high strength coupled with high thermal conductivity and thus is useful not only as various parts for semiconductor devices, such as radiating insulating substrates, but as various structural parts for machines, OA apparatuses, etc.