Abstract: An anode active material for lithium ion batteries includes one or more unaggregated silicon particles having a mass-based chlorine content of from 5 to 200 ppm and a volume-weighted particle size distribution having diameter percentiles d50 of from 0.5 ?m to 10.0 ?m.

Abstract: A silicon nitride-based sintered body containing silicon nitride-based grains, which are silicon nitride grains or sialon grains. In the silicon nitride-based sintered body, when the size of each silicon nitride-based grain is represented by its maximum grain size, the ratio of the number of silicon nitride-based grains having a maximum grain size of 1 ?m or less to the number of the entire silicon nitride-based grains is 70% or higher. Furthermore, in the distribution profile of no. % of silicon nitride-based grains with respect to maximum grain size, the maximum value of no. % (i.e., maximum no. %) of silicon nitride-based grains is 15 no. % or higher. Also disclosed is a cutting insert, which is formed of the silicon nitride-based sintered body.

Abstract: A low-cost, durable silicon carbide member for a plasma processing apparatus. The silicon carbide member for a plasma processing apparatus can be obtained by processing a sintered body which is produced with a method in which metal impurity is reduced to more than 20 ppm and 70 ppm or less, and an ?-structure silicon carbide power having an average particle diameter of 0.3 to 3 ?m and including 50 ppm or less of an Al impurity is mixed with 0.5 to 5 weight parts of a B4C sintering aid, or with a sintering aid comprising Al2O3 and Y2O3 with total amount of 3 to 15 weight parts, and then a mixture of the ?-structure silicon carbide power with the sintering aid is sintered in an argon atmosphere furnace or a high-frequency induction heating furnace.

Abstract: A gettered polycrystalline group III metal nitride is formed by heating a group III metal with an added getter in a nitrogen-containing gas. Most of the residual oxygen in the gettered polycrystalline nitride is chemically bound by the getter. The gettered polycrystalline group III metal nitride is useful as a raw material for ammonothermal growth of bulk group III nitride crystals.

Abstract: The invention relates to a shaped body comprising a substrate with a firmly adhering separating layer, wherein the separating layer comprises 92-98 wt. % silicon nitride (Si3N4) and 2-8 wt. % silicon dioxide (SiO2) and wherein the separating layer has a total oxygen content of ?8 wt. % and a hardness of at least 10 HB 2.5/3 according to DIN EN ISO 6506-1. The invention further relates to a process for producing such a shaped body, a coating suspension for use in such a process and the use of a shaped body according to the invention in the field of corrosive nonferrous metal melts.

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: An article including a monolithic crucible body comprising silicon oxynitride (SixNyO, wherein x>0 and y>0), wherein the silicon oxynitride extends throughout the entire volume of the monolithic crucible body.

Abstract: Methods of forming an insulating material comprising combining a polysilazane, a cross-linking compound, and a gas-generating compound to form a reaction mixture, and curing the reaction mixture to form a modified polysilazane. The gas-generating compound may be water, an alcohol, an amine, or combinations thereof. The cross-linking compound may be an isocyanate, an epoxy resin, or combinations thereof. The insulating material may include a matrix comprising one of a reaction product of a polysilazane and an isocyanate and a reaction product of a polysilazane and an epoxy resin. The matrix also comprises a plurality of interconnected pores produced from one of reaction of the polysilazane and the isocyanate and from reaction of the polysilazane and the epoxy resin. A precursor formulation that comprises a polysilazane, a cross-linking compound, and a gas-generating compound is also disclosed.

Abstract: A process for manufacturing a sintered ceramic composite, based on silicon nitride and ?-eucryptite, includes a step of producing a first powder blend, consisting of a powder of silicon nitride in crystalline form and a powder of a first lithium aluminosilicate in crystalline form, the composition of which is the following: (Li2O)x(Al2O3)y(SiO2)z, the lithium aluminosilicate composition being such that the set of molar fractions (x,y,z) is different from the set (1,1,2).

Abstract: The invention provides a vessel for molten metal comprising a vessel body formed of an alumina-silica-based material, and a protective layer formed of a silicon nitride- alumina-based material provided on the inner surface of the vessel body, wherein the material for the vessel body is adjusted to have an alumina content x of 72 to 95 parts by weight per 100 total parts by weight of alumina and silica, and the material for the protective layer is adjusted to have a silicon nitride content y per 100 total parts by weight of silicon nitride and alumina in such a manner that y applies to the following formulae: (1) y<?1.1x+128 and (2) y>?0.5x+62.5. The present invention provides a vessel for molten metal having excellent durability and corrosion resistance against hot molten metal.

Abstract: Disclosed are cement compositions for applying to honeycomb bodies. The cement compositions can be applied as a plugging cement composition, segment cement, or even as after applied artificial skins or coatings. The cement compositions generally include an inorganic powder batch mixture consisting essentially of inorganic particles having a particle size greater than 100 nm. The cement compositions can further include an organic binder, a liquid vehicle, and one or more optional processing aids. Also disclosed are honeycomb bodies having the disclosed cement compositions applied thereto and methods for making same.

Abstract: It is intended to provide a taphole mix capable of forming SiC bonds with minimum of an excess and a deficiency in components thereof, and excellent in drillability. A fine particle fraction having a particle diameter of 75 ?m or less is comprised of three components consisting of a silicon nitride-based material, a carbon-based material, and roseki, or comprised of the three component, and one or more selected from the group consisting of an alumina-based material, a silicon carbide-based material, a rare-earth element oxide-based material, clay, a high-purity silica-based material containing SiO2 in an amount of 80 mass % or more, a boron compound-based material in an amount of less than 0.3 mass % with respect to 100 mass % of the silicon nitride-based material, and a metal powder in an amount of less than 10 mass % with respect to 100 mass % of the carbon-based material.

Abstract: A silicon nitride sintered compact contains silicon nitride grains, and a sintering aid component in a range of 2 to 15 mass %. The silicon nitride grains include needle crystal grains each having a long diameter L of 10 ?m or less and a ratio (L/S) of the long diameter L to a short diameter S of 5 or more, by 50% or more in area ratio in a crystalline structure of the silicon nitride sintered compact. The silicon nitride sintered compact is used as a sliding member like a bearing ball (2).

Abstract: Isopipes (13) for making a glass or a glass-ceramic using a fusion process are provided. The isopipes are made from a silicon nitride refractory material that is: (a) produced in block form in an atmosphere having a pO2 of less than 0.1 using less than 10 weight percent of one or more sintering aids, (b) machined into an isopipe configuration, and (c) exposed to a partial pressure of oxygen equal to or greater than 0.1 for a period of time and at a temperature sufficient to form a SiO2 layer (31) which exhibits substantially only a passive oxidation mechanism. The SiO2 layer (31) serves as a protective barrier for further oxidation of the silicon nitride during use of the isopipe (13). The isopipes (13) exhibit less sag during use than isopipes composed of zircon.

Abstract: Process for the preparation of a ceramic wherein: 50% to 75% by weight of a compound intended to form a conductive phase, and 25% to 50% by weight of one or more materials allowing the formation of insulating phases composed of silicon nitride and modified silicon oxynitride are mixed in a receptacle containing a liquid after a thermal treatment leading to sintering of the ceramic; this mixture is subjected to grinding, drying and sieving operations; this mixture is pressed; and this mixture is sintered so as to obtain a ceramic with a porosity of between 0 and 30%. The sintering is carried out under a pressure of at least 50 bar of a gas which is inert towards the constituents of the mixture. Ceramic thus obtained and spark plug comprising it.

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: The invention relates to a fired refractory ceramic product. According to the invention, this generic term encompasses both shaped and unshaped products. Shaped products are ones which have a defined shape so that they can be manufactured in finished form on the premises of the manufacturer. Shaped products include: bricks, nozzles, tubes, stoppers, plates, etc. The term unshaped products includes ones which are usually produced by the user from a corresponding composition. They include bases for furnaces which are cast from a composition but also repair compositions, etc.

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 method of forming a preceramic polymer includes treating a silane precursor having a vinyl moiety of ammonia to produce the preceramic polymer. For example, the silane precursor is trichlorovinylsilane. The preceramic polymer may then be cross-linked at a relatively low temperature by using a cross-linking agent.

Abstract: A refractory material used in refractory furnace liners, combustion chambers, baffles and artificial fire logs includes alumina silicate; an additive comprising at least one of silicon carbide, silicon nitride, boron carbide, boron nitride and silicon carbo-nitride; and a binder. The refractory material is light weight, has a high noise reduction capacity, is fire resistant and has a reduced silica content. In a most preferred embodiment, the additive makes up 50.0% to 55.0% of the material by weight, the binder makes up 4.5% to 5.0% of the material by weight and the linear shrinkage of the material is no greater than 3.5% at 2600° F. A preferred binder is colloidal silica although many others are suitable. Preferably, the material is free of cellulose fiber and sodium silicate.

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: A method of forming a nanoscale ceramic composite generally includes modifying a polymeric ceramic precursor, mixing the modified polymeric ceramic precursor with a block copolymer to form a mixture, forming an ordered structure from the mixture, wherein the modified polymeric ceramic precursor selectively associates with a specific type of block of the block copolymer, and heating the ordered structure for a time and at a temperature effective to form the nanoscale ceramic composite.

Abstract: A ceramic material for an optical member which shows black, wherein the ceramic material comprises a reaction-sintered sintered ceramic body prepared by synthesizing a formed body of a mixture comprising a ceramic raw material and a component that accelerates blackening, making use of a reaction sintering; and wherein the ceramic material is a porous body.

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: A novel process for the preparation of boron carbide, boron nitride and silicon carbide powders comprises carbidization or nitrization step of boron oxide or silicon oxide respectively, using nanoparticles substrates.

Abstract: A silicon nitride sintered compact contains silicon nitride grains, and a sintering aid component in a range of 2 to 15 mass %. The silicon nitride grains include needle crystal grains each having a long diameter L of 10 ?m or less and a ratio (L/S) of the long diameter L to a short diameter S of 5 or more, by 50% or more in area ratio in a crystalline structure of the silicon nitride sintered compact. The silicon nitride sintered compact is used as a sliding member like a bearing ball (2).

Abstract: Preparation for producing refractory materials, characterized in that it comprises one or more particulate, refractory components and one or more binders, where—the particulate, refractory component has a mean particle diameter of >0.3 m and—the binder is selected from among—from 0.05 to 50% by weight of a very finely particulate binder having a mean particle diameter of from 10 nm to 0.3 m selected from the group consisting of aluminium oxide, titanium dioxide, zirconium dioxide and/or mixed oxides of the abovementioned oxides, —from 0 to 20% by weight of an inorganic binder, from 0 to 20% by weight of a hydraulically setting binder, —from 0 to 15% by weight of an organic, silicon-free binder—and the preparation additionally contains from 0 to 35% by weight of water, where—the proportion of the particulate, refractory component is equal to 100 and the percentages of the further materials in the preparation are based on the particulate component.

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: Provided are a silicon nitride substrate and a silicon nitride circuit board with excellent electrical characteristics, and power control parts utilizing them. A silicon nitride substrate comprises a silicon nitride sintered body obtainable by sintering a silicon nitride powder in the presence of a sintering aid comprising MgO, Y2O3 and SiO2 in a proportion of (1) MgO/(MgO+SiO2)=34-59 mol %, and (2) Y2O3/(Y2O3+SiO2)=50-66 mol %, and a silicon nitride circuit board utilizes it.

Abstract: A method for forming porous ceramic objects is provided, in which a suspension of ceramic precursor particles in a solution of gelatin is allowed to gel in the desired shape, and is then dried and sintered to the desired level of porosity.

Abstract: The present invention relates to refractory articles in general having improved surface properties. The objective of the invention is to propose an improvement of the refractory articles comprised of a fused silica matrix which will overcome the some of the defects while keeping the excellent known properties of the fused silica matrix. This objective is reached when a sintered ceramic phase is present in the porosity of at least a portion of at least a surface of the matrix. The present invention also relates to a process for producing such an article.

Abstract: There is disclosed a pre-sintering process for reducing non-uniformities in the density of a sintered material comprising (a) providing a mixture of (i) a first sinterable material containing a contaminant the presence of which during sintering of the first sinterable material results in a higher vapor pressure than would occur during sintering of pure first sinterable material and (ii) a second material having a higher affinity for the contaminant than does the first sinterable material; and (b) heating the mixture at a temperature and for a time sufficient to allow the second material to at least partly mitigate the propensity of the contaminant to raise the vapor pressure during the sintering of the first sinterable material. Other embodiments are also disclosed.

Abstract: A process for producing a silicon nitride compound is presented. A starting solution comprising fluorosilicic acid is provided. The starting solution is derived from a silicon, etching process wherein silicon is etched with a solution comprising hydrofluoric acid and where silicon powder has been removed. The starting solution is heated to yield a vapor solution comprising silicon tetrafluoride, hydrogen fluoride, and water. The hydrogen fluoride is separated from the vapor solution wherein a pure stream of silicon tetrafluoride and water vapor remain. The silicon tetrafluoride and water vapor are hydrolyzed to yield a concentrated fluorosilicic acid solution. The fluorosilicic acid is reacted with a base to yield a fluorosilicic salt. The fluorosilicic salt is heated to yield anhydrous silicon tetrafluoride. The anhydrous silicon tetrafluoride is reacted with a metal hydride to yield a monosilane. The monosilane is reacted to form a silicon compound and a silicon nitride compound.

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: The present invention is characterized in that a base material is coated with a ceramic thin film comprising a composite phase composed of a first phase mainly formed of a silicon ceramic component and a second phase mainly formed of a ceramic component other than the silicon ceramic component of the first phase, in which the amount of fine crystal particles of at least one ceramic component that constitutes the second phase slopingly increases toward a surface layer. According to the present invention, there are provided a ceramic thin film coating material having a slope constitution, which not only has an excellent function such as a photocatalyst function, an electrical function, a thermal catalyst function or a catalyst-supporting function or environment resistance such as oxidation resistance, alkaline resistance or wear resistance but also has excellent dynamic properties, and a process for the production thereof.

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 refractory material used in refractory furnace liners, combustion chambers, baffles and artificial fire logs includes alumina silicate; an additive comprising at least one of silicon carbide, silicon nitride, boron carbide, boron nitride and silicon carbo-nitride; and a binder. The refractory material is light weight, has a high noise reduction capacity, is fire resistant and has a reduced silica content. In a most preferred embodiment, the additive makes up 50.0% to 55.0% of the material by weight, the binder makes up 4.5% to 5.0% of the material by weight and the linear shrinkage of the material is no greater than 3.5% at 2600° F. A preferred binder is colloidal silica although many others are suitable. Preferably, the material is free of cellulose fiber and sodium silicate.

Abstract: A method for improving surface thermal shock resistance of a member made of ceramics to which thermal shock resistance is required comprising, forming homogeneously distributed linear dislocation structure on the surface of the member made of ceramics to which thermal shock resistance is required by blasting abrasives composed of fine particles whose average particle size is from 5 ?m to 200 ?m and whose surface shape is convex, wherein Vickers hardness (HV) of said fine particles is 800 or more and equal to or less than the hardness of the member made of ceramics to which thermal shock resistance is required.

Abstract: Multiphase ceramic nanocomposites having at least three phases are disclosed. Each of the at least three phases has an average grain size less than about 100 nm. In one embodiment, the ceramic nanocomposite is substantially free of glassy grain boundary phases. In another embodiment, the multiphase ceramic nanocomposite is thermally stable up to a temperature of at least about 1500° C. Methods of making such multiphase ceramic nanocomposites 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: A ceramic material for an optical member which shows black, wherein the ceramic material comprises a reaction-sintered sintered ceramic body prepared by synthesizing a formed body of a mixture comprising a ceramic raw material and a component that accelerates blackening, making use of a reaction sintering; and wherein the ceramic material is a porous body.

Abstract: A slip-casted article former containing ternary ceramics, particularly of carbide and nitride materials, having the formula M.sub.n+1AX.sub.n (MAX), where M is a transition metal, A is an element from Groups IIIA and IVA of the periodic table, X is nitrogen or carbon and n is 1, 2, or 3. The ternary ceramic article may be a glove or condom former. A process for making a ternary ceramic article employing a slip cast method.

Abstract: The present invention provides a method for making a microporous ceramic material and includes the steps of (a) preparing a starting material for firing comprising a nonoxide ceramic precursor containing silicon as an essential component; (b) heating the starting material for firing in an atmosphere containing at least 1 mol % of hydrogen so as to form microporous ceramic product; and (c) cooling the microporous ceramic product.

Abstract: A method of making nanoscale ordered composites of covalent ceramics through block copolymer-assisted assembly. At least one polymeric precursor is mixed with a block copolymer, and self-assembly of the mixture proceeds through an annealing process. During the annealing step, the polymeric precursor cross-links to form a structure robust enough to survive both the order-disorder transition temperature the block copolymer and the pyrolysis process, yielding ordered nanocomposites of high temperature ceramic materials. The method yields a variety of structures and morphologies. A ceramic material having at least one ceramic phase that has an ordered structure on a nanoscale and thermally stable up to a temperature of at least about 800° C. is also disclosed. The ceramic material is suitable for use in hot gas path assemblies, such as turbine assemblies, boilers, combustors, and the like.

Abstract: The invention provides porous silicon nitride ceramics that having uniform, fine closed pores and a manufacturing method thereof. Metal Si powder is mixed with a sintering additive, followed by thermal treatment, which is a pre-process for forming a specific grain boundary phase. Two-stage thermal treatment is thereafter performed by microwave heating at a temperature of 1000° C. or more. The metal Si powder is thereafter subjected to a nitriding reaction from its surface, the metal Si is thereafter diffused to nitride formed on the outer shell thereof such that porous silicon nitride ceramics having uniform, fine closed pores can be produced. Having a high ratio of closed pores and being superior in electrical/mechanical characteristics, the porous silicon nitride ceramics can display excellent characteristics if used, for example, for an electronic circuit board that requires an anti-hygroscopicity, a low dielectric constant, a low dielectric loss, and mechanical strength.

Abstract: The present invention provides a silicon nitride-based sintered body having excellent mechanical properties from room temperature to a medium-low temperature range, a low friction coefficient and excellent wear resistance; a raw material powder for the sintered body; a method of producing the raw material powder; and a method of producing the sintered body. The sintered body of the present invention comprises silicon nitride, titanium compounds and boron nitride, or else silicon nitride, a titanium-based nitride and/or carbide, silicon carbide and graphite and/or carbon; and it has a mean particle diameter of 100 nm or less, and a friction coefficient under lubricant-free conditions of 0.3 or less, or else 0.2 or less.

Abstract: A large amount of spinel type silicon nitride powders of a high-pressure phase is produced by mixing raw powders having a particle size of 10 ?m or less of ?-, ?- or amorphous silicon nitride, each of which is a low pressure phase, with non-nitrified metal powders at a ratio of 50 weight % or more, preferably copper powders with a particle size of 100 ?m or less, forming a compact with porosity of 50% or less and 10% or more, preferably around 30%, by pressing mixture powders obtained, and subjecting the compact to shock wave compression treatment at a pressure of 20 GPa or more, preferably around 60 GPa.

Abstract: When a sintered body of ceramic is shot-blasted at normal temperatures to plastically deform the crystal structure of the shot-blasted surface to apply residual stress and is heat-treated to recrystallize fine cracks, dislocated cells in the grain boundary are formed, crystals are finely divided, and the fracture toughness is significantly improved. When the sintered body of ceramic is a thin product, an effective toughening can be attained by shot blasting both the front and back sides. After heat treatment, mechanical strength is significantly improved by removing a part of the modified surface layer by an abrasion treatment.

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 silicon nitride member, a method for manufacturing the silicon nitride member and a cutting tool are disclosed. A cutting tool 1 includes a substrate 3 formed through sintering of a silicon nitride material, and a hard film 5 composed of a plurality of hard-component layers. The cutting tool 1 is characterized in that: when the amount of a grain boundary phase as measured at a central portion (for example, the barycenter) of the substrate 3 is taken as 100% by volume, the amount of the grain boundary phase at a depth of 300 ?m from the surface of the substrate 3 is 50% to 70% by volume; when the strength of the substrate 3 as measured before coating with the hard film 5 is taken as 100%, the hardness as measured after coating with the hard film 5 is 70% to 95%; and a change in weight of the substrate 3 associated with sintering is 1.5% to 3.5% by weight.