Abstract: Disclosed is a molding method for powder particles, which is excellent in molding performance, and which makes it possible to obtain a preliminary molded product excellent in strength by enhancing mutual bonding between particles in the preliminary molded product. A molding apparatus for powder particles includes an outer frame die having a mold space with a lower punch and an upper punch to be slidably fitted thereto. Slight clearances exist between the outer frame die and the lower and upper punches. A mixture is prepared by mixing a powdery raw material with a liquid additive to cause an exothermic reaction therewith.

Abstract: Disclosed is a ceramic cutting tool comprising in its essential part a ceramic material comprising, in one aspect, a titanium carbonitride-based hard phase and an alumina-based phase, wherein the ceramic material satisfies the following relationships: 10 wt %≦weight of Al2O3≦45 wt %; 51 wt %≦weight of TiCN≦89.5 wt %; and 96 wt %≦weight of Al2O3+weight of TiCN≦99.5 wt % wherein the weight of Al2O3 indicates the weight content of aluminum as calculated in terms of Al2O3; and the weight of TiCN indicates the weight content of said titanium carbonitride hard phase,with the proviso that the weight of TiCN is defined by the weight of Ti+ the weight of C+ the weight of N, in which weight of Ti, C, and N are the weight contents of the titanium component, carbon component, and nitrogen component, respectively.

Abstract: In one aspect, the invention includes a method of forming a material containing carbon and boron, comprising: a) providing a substrate within a chemical vapor deposition chamber; b) flowing a carbon and boron precursor into the chamber, the precursor being a compound that comprises both carbon and boron; and c) utilizing the precursor to chemical vapor deposit a material onto the substrate, the material comprising carbon and boron. In another aspect, the invention includes a method of forming a catalyst, comprising: a) providing a substrate within a chemical vapor deposition chamber; b) flowing a carbon and boron precursor into the chamber, the precursor being a compound that comprises both carbon and boron; c) utilizing the precursor to chemical vapor deposit a first material onto the substrate, the first material comprising carbon and boron; and d) coating the first material with a catalytic material.

Abstract: High-temperature, lightweight, ceramic carbon insulation is prepared by coating or impregnating a porous carbon substrate with a siloxane gel derived from the reaction of an organodialkoxy silane and an organotrialkoxy silane in an acid or base medium in the presence of the carbon substrate. The siloxane gel is subsequently dried on the carbon substrate to form a ceramic carbon precursor. The carbon precursor is pyrolyzed, in an inert atmosphere, to form the ceramic insulation containing carbon, silicon, and oxygen. The carbon insulation is characterized as a porous, fibrous, carbon ceramic tile which is particularly useful as lightweight tiles for spacecraft.

Abstract: A molybdenum carbide compound is formed by reacting a molybdate with a mixture of hydrogen and carbon monoxide. By heating the molybdate powder from a temperature below 300° C. to maximum temperature 850° C., a controlled reaction can be conducted wherein molybdenum carbide is formed. A high surface area, nanograin, metastable molybdenum carbide can be formed when the reaction temperature is below 750° C. The metastable molybdenum carbide is particularly suitable for use as a catalyst for the methane dry reforming reaction.

Abstract: A ceramic composition produced by the consolidation of a blend of starting components. The composition comprises a matrix with one or more of the carbides, nitrides and carbonitrides of hafnium, molybdenum, zirconium, tantalum, niobium, vanadium and tungsten, titanium nitride, and titanium carbonitride in an amount that is greater than 50 volume percent of the matrix. The matrix comprises between 60 and 99.8 volume percent of the composition. Ceramic whiskers are uniformly dispersed throughout the matrix wherein the ceramic whiskers comprises between 0.2 and 40 volume percent of the composition.

Abstract: A cermet or hard metal body is formed from elemental metal, carbon and a nitrogen source such as a metal nitride or an organic nitrogen source by microwave sintering such that chemical reaction occurs with the formation of carbides and/or carbonitrides. The elemental metal, carbon and nitrogen source are mixed together and prepressed to form the green body which is subjected to the microwave radiation in reaction sintering.

Abstract: A heat insulating molded body made of inorganic material and inorganic reinforcement fibers is disclosed, as well as a process for producing the same and its use. The molded body is characterized by the following composition: (a) 30-70 wt. % blown vermiculite; (b) 15-40 wt. % inorganic binder; (c) 0-20 wt. % infrared opacifier; (d) 15-50 wt. % microporous material; (e) 0.5-8 wt. % reinforcement fibers which contain maximum 2 wt. % B2O3 and at most 2% alkalimetal oxide, based on the weight of the reinforcing fibers.

Abstract: A tungsten carbide surface is finished to an RMS surface roughness of about 25 nm (1.0 microinch) or less by abrasion using diamond grit particles. The tungsten carbide surface is abraded by a sequence of grit particle-containing abrasive members, such as abrasive films, pastes, or slurries, at least one of the members having an average grit particle diameter of about 2 &mgr;m or less. The finish is enhanced by oscillating the abrasive member back and forth over the tungsten carbide surface. A different speed is used for at least two consecutive films in the series, thereby generating scratches at different angles which can be distinguished. A superfinish, corresponding to a lack of visible scratches at 100× magnification, can be obtained by abrading the tungsten carbide surface with a diamond slurry or paste having grit particles with an average diameter of about 1 &mgr;m or less.

Abstract: The production of open-celled porous inorganic sintered products comprises the stepsa) introducing a flowable mixture comprising an aqueous polymer dispersion, sinterable inorganic powder and dispersant into a precipitation bath in which the polymer precipitates or coagulates to form a non-flowable product comprising polymer, inorganic powder and dispersant,b) removing the product from the precipitation bath and drying the product,c) heating the product to remove polymer and dispersant and sintering the product.The porous open-celled sintered products comprising sintered inorganic powder have a pore volume of from 50 to 95%, a surface area of from 0.1 to 50 m.sup.2 /g and an at least bimodal pore size distribution having maxima in the ranges from 0.02 to 5 .mu.m and from 20 to 500 .mu.m.

Abstract: A nuclear medical drug for localize radiotheraphy of a tumor and methods for its preparation. The drug includes a radioactive ceramic or glass particle having biocompatiblity. Ceramic or glass particles prepared by traditional processes become radioactive particles with pure .beta.-particle-emitting radionuclides after being irradiated with an appropriate flux of neutrons. The radioactive particle with suitable particle size can then be dispersed into a contrast medium for injection or can be implanted by operation.

Abstract: The polycrystalline cubic boron nitride cutting tool has a particle size in the range of from 10-17 microns. In addition to CBN, the tool has from 2%-15% by weight of a refractory compound selected from the group consisting of titanium carbonitride, titanium aluminum carbonitride, titanium carbide, titanium nitride, titanium diboride and aluminum diboride. When using one of the carbonitrides, the carbon to nitrogen proportion is preferably in the range of from 30 atomic percent carbon and 70 atomic percent nitrogen to 70 atomic percent carbon and 30 atomic percent nitrogen, and preferably is about 50 atomic percent carbon and 50 atomic percent nitrogen. In addition, there is an infiltrant containing aluminum and/or silicon. The cutting tool is not formed on a cemented tungsten carbide substrate so is substantially free of cobalt.

Abstract: This invention provides an alumina base ceramic sintered body excellent in wear resistance with high hardness, also with high strength and high toughness, and particularly suitable for a cutting tool or wear resistant member. This sintered body contains 5-70 % by volume of WC and 5-70% by volume of Ti (C,N) solid solution having a C/N mole ratio ranging from 1:9 to 9:1, the WC and Ti (C,N) having particle sizes of 5 .mu.m or less, respectively.

Abstract: This invention relates generally to a novel directed metal oxidation process which is utilized to produce self-supporting bodies. In some of the more specific aspects of the invention, a parent metal (e.g., a parent metal vapor) is induced to react with at least one solid oxidant-containing material to result in the directed growth of a reaction product which is formed from a reaction between the parent metal and the solid oxidant-containing material. The inventive process can be utilized to form bodies having substantially homogeneous compositions, graded compositions, and macrocomposite bodies.In a preferred embodiment, the reaction product may be chemically modified or a different reaction product may be coated thereon. Specifically, once a first reaction product is formed on a solid oxidant-containing material, the formed body may be exposed to a vapor-phase parent metal different from the first parent metal.

Abstract: The present invention relates to a method for the formation of amorphous boron silicon oxycarbide fibers and crystalline boron-doped silicon carbide fibers wherein the method comprises preparing a blend of a siloxane resin and a carborane-siloxane oligomer, forming the blend into green fibers, and then curing and pyrolyzing the fibers.

Abstract: High emissivity molybdenum silicide-containing ceramic and metal-ceramic products are provided, especially for use as heaters in rapid solidification processing (RSP) and rapid thermal processing (RTP). Novel designs incorporating such heaters are also provided.

Abstract: An aluminum-boron-carbon abrasive article is comprised of at least three phases selected from the group consisting of: B.sub.4 C; AlB.sub.2 ; AlB.sub.12 ; AlB.sub.12 C.sub.2 ; Al.sub.4 C.sub.3 ; AlB.sub.24,C.sub.4 ; Al.sub.4 B.sub.1-3 C.sub.4 ; AlB.sub.24 C.sub.4 and Al.sub.4 BC. At least a portion of the surface of the abrasive article is comprised of abrasive grains of at least one phase selected from the group consisting of AlB.sub.24 C.sub.4, Al.sub.4 BC and AlB.sub.2, where the abrasive grains have an average grain size that is at least about two times greater than the average grain size of the grains containing boron and carbon within the abrasive article. The aluminum-boron-carbon abrasive article of claim 1 is prepared by heating, under a vacuum or inert atmosphere, a body comprised of at least one boron containing phase and at least one carbon containing phase in the presence of a separate source of aluminum, such as aluminum metal or alloy thereof.

Abstract: A wear resistant coating for journals, journal sleeves and bushings on submerged rolls in a molten metal coating bath, comprising a laser-melted tungsten carbide containing overlay.

Abstract: A sintered hard material according to the invention comprises 0.02 to 0.10 wt % of one or more metals selected from the group consisting of Fe, Co and Ni, 0.3 to 3.0 wt % of one or more compounds selected from the group consisting of carbides, nitrides and carbonitrides of transition metals of the IVa, Va and VIa groups of the periodic table and a residue of tungsten carbide component having an average particle size of 0.5 .mu.m or less, the tungsten carbide component containing WC and W.sub.2 C in a proportion W.sub.2 C/(WC+W.sub.2 C) of between 0.01 and 0.15, the W.sub.2 C in the tungsten carbide component having a lattice constant reduced by 0.3 to 1.5 %.

Abstract: A ceramic formed body containing a) 5 to 70 vol % of at least on intermetallic aluminide phase which additionally may contain aluminum or/and aluminum alloy, and b) 30 to 95 vol % of one or more ceramic phases which form a solid interconnecting skeleton and wherein the intermetallic phase or phases consist of predominantly interconnected areas with average sizes of 0.1 to 10 .mu.m, is obtained by sintering, in a non-oxidizing atmosphere, of a powder metallurgically green body which consists of a mixture of finely dispersed powder of aluminum, one or more ceramic substances and maybe further metals such that the mixture contains at least one oxide ceramic or/and metallic powder which, during sintering, reacts with aluminum thereby forming an aluminide and maybe Al.sub.2 O.sub.3.

Abstract: The present invention is ceramic article of stabilized zirconia wherein the stabilized zirconia has a molar ratio of rare earth oxide:zirconia of from 1:99 to 15:85, at a weight percent of from about 97 to 75. The ceramic article includes smectite clay from about 3 to 25 weight percent wherein the article is a mass of sintered particles having a continuous tetragonal phase having dispersed therein monoclinic phase particles having size of less than 100 nm.

Abstract: Metal carbide-containing refractory materials are prepared by pyrolysing blanks comprising reactive metal sources and carbon-containing precursors under fluid pressure, e.g., using hot isostatic pressing techniques. Refractory composites containing ceramic fillers, reinforcing materials such as carbon fillers, excess carbon or excess metal are readily prepared thereby.

Abstract: A pigmented silicon nitride composition suitable for hot pressing into near shape articles of manufacture having a cosmetically uniform color. The composition comprises high purity, sub-micrometer, alpha silicon nitride powder mixed with a sintering aid and a pigmenting material. In a preferred embodiment the pigmenting material comprises molybdenum carbide, although carbides of other elements are applicable as well. The resulting hot pressed article is cosmetically superior to non-pigmented silicon nitride. Such articles are especially useful for processing semiconductor components where appearance in the form of color uniformity is a strict requirement for the manufacturer and the customer.

Abstract: A hard sintered body for a tool contains 25 to 47 vol. % of cBN, 40 to 70 vol. % and especially less than 45 vol. % in total of a carbo-nitride, and a boride of Ti, and 2 to 20 vol. % in total of a boride and a nitride of Al. In the carbo-nitride of Ti, the ratio of carbon to nitrogen is in the range of 60:40 to 30:70. In this hard sintered body, cBN particles are bonded to each other through binder phases. The obtained hard sintered body for a tool is excellent in wear resistance and chipping resistance for high-speed cutting of hardened steel.

Abstract: A sintered body consists of high-pressure phase boron nitride, a residual binder phase and an unavoidable impurity, and contains high-pressure phase boron nitride powder which is previously coated with a binder before sintering. The coating binder consists of an element belonging to the group 4a, 5a or 6a of the periodic table or the like, and has an average thickness of 5 to 300 nm. Binder powder other than the coating binder consists of an element belonging to the group 4a, 5a or 6a of the periodic table or the like, and a contact ratio of high-pressure phase boron nitride particles in surface-to-surface contact with each other is at least 20% and less than 50%. The resulting high-pressure phase boron nitride-based hard and tough sintered body for a cutting tool is improved in wear resistance and chipping resistance.

Abstract: A sintered ceramic body which can be worked by electrical discharge machining, has high mechanical strength, and can be worked into sintered ceramic tools which have long life is disclosed. Further, sintered ceramic tools which have long life and scarcely cause flaws in work pieces are provided. The sintered ceramic body comprises ceramic particles having specific particle diameter and particle distribution.

Abstract: The present invention is embodied in a ceramic foam made by mixing a liquid pre-ceramic resin and a liquid phenolic resin, allowing the resultant mixture to chemically foam, curing the mixture for a time and at a temperature sufficiently to convert the mixture to a polymeric foam, and then heating the resultant polymeric foam for a time and at a temperature sufficient to break-down polymers of the polymeric foam and convert the polymeric foam to a ceramic foam. The ceramic foam of the present invention contains residual decomposed components of the liquid phenolic resin and/or liquid pre-ceramic resin.

Abstract: Methods for the manufacture of nanostructured metals, metal carbides, and metal alloys are presented, such metals including nanostructured aluminum, chromium, iron, molybdenum, vanadium, and steel. Preferably, the nanostructured steel is of the M50 type, and comprises iron, molybdenum, chromium, vanadium and carbon. Synthesis of M50 steel further comprising nanostructured aluminum, aluminum oxide, or aluminum nitride is also described. In accordance with an important feature of this invention, the grain size of the metals and metal alloys is in the nanometer range. In accordance with the method of the present invention, the nanostructured metals, metal carbides, and metal alloys are prepared via chemical synthesis from aluminum, iron, molybdenum, chromium and vanadium starting materials. Decomposition of metal precursors or co-precipitation or precipitation of metal precursors is followed by consolidation of the resulting nanostructured powders.

Abstract: A ceramic composition produced by the consolidation of a blend of starting components. The composition comprises a matrix with one or more of the carbides, nitrides and carbonitrides of hafnium, molybdenum, zirconium, tantalum, niobium, vanadium and tungsten, titanium nitride, and titanium carbonitride in an amount that is greater than 50 volume percent of the matrix. The matrix comprises between 60 and 99.8 volume percent of the composition. Ceramic whiskers are uniformly dispersed throughout the matrix wherein the ceramic whiskers comprises between 0.2 and 40 volume percent of the composition.

Abstract: Oxide-based ceramic cutting inserts for chipforming machining of steel, comprising a ceramic oxide-based matrix of alumina and less than 10% by volume zirconia and 5-40% by volume of homogeneously dispersed whiskers based upon (Ta.sub.x Hf.sub.y Ti.sub.1-x-y)C.sub.1-z N.sub.z where 0<x<0.75 and 0<y<0.75, x+y>0.25 and 0.ltoreq.z<1.

Abstract: A hardfacing material for shirttail and gage surfaces of a rock bit cone and a gage row of rock bit teeth comprises steel in the range of from 20 to 40 percent by weight, and tungsten carbide particles in the range of from 60 to 80 percent by weight which contains single crystal monotungsten carbide particles having a particle size primarily less than about 200 mesh with a preferred average particle size in the range of from 30 to 70 microns. According to further embodiments, carburized tungsten carbide particles and/or spherical cast carbide particles are mixed with the single crystal monotungsten carbide in the hardfacing. The carburized tungsten carbide particles have a particle size in the range of from about 10 to 50 microns. The spherical cast tungsten carbide particles have a particle size in the range of from about 20 to 150 microns. The particle size distributions of the tungsten carbide particles are bimodal or trimodal for improved weldability and wear resistance in the hardfacing.

Abstract: A powdered mixture of chemicals for forming a refractory composition, including a filler consisting of refractory particles, metal particles and metal peroxide containing particles, wherein the metal peroxide containing particles have a calcium peroxide content of at most 75 wt %, a magnesium peroxide content of at most 30 wt %, a barium peroxide content of at most 92 wt %, and/or a strontium peroxide content of at most 90 wt %. A refractory composition prepared from said mixture, a method for forming said composition and a method for using same are also disclosed.

Abstract: A composite ceramic coating having abrasive properties for application to a metallic substrate is provided which includes a ceramic matrix and a plurality of ceramic abrasive particles disposed within said ceramic matrix. The abrasive particles have a shear strength substantially greater than that of the ceramic matrix and possess an angular geometry. A method for providing an abrasive coating on a metallic article is also provided.

Abstract: The invention concerns a zirconia based ceramic article having a core of ZrO2 and/or partially reduced ZrO2, characteriZed in that it includes, over at least part of its surface, a superficial layer integral with said article, the thickness of said superficial layer including a plurality of regions of which one external region is formed of zirconium carbide having a metallic appearance.

Abstract: In order to provide cemented carbide, provision is made about tungsten carbide powder which has a grain size not smaller than 1 .mu.m and which is mixed with carbon powder and chromium powder to form raw powder. The tungsten carbide powder is formed by fine primary crystal particles of tungsten carbide and satisfies an inequality given by:Y>0.61-0.33 log (X),where Y denotes a half-value width of (211) crystal planes in tungsten carbide (JCPDS-card 25-1047, d=0.9020) measured by a X-ray diffraction method and where X denotes a grain size measured by the FSSS method. There is also provided a method of producing the composite carbide powder having tungsten carbide powder as a main element, the method comprising the steps of preparing tungsten powder which has a mean grain size not smaller than 1 .mu.m, mixing the tungsten powder with carbon powder and chromium powder into a mixture, and processing the mixture in a predetermined atmosphere into fine primary crystal particles of tungsten carbide.

Abstract: A sintered ceramic body which can be worked by electrical discharge machining, has high mechanical strength, and can be worked into sintered ceramic tools which have long life is disclosed. Further, sintered ceramic tools which have long life and scarcely cause flaws in work pieces are provided. The sintered ceramic body comprises ceramic particles having specific particle diameter and particle distribution.

Abstract: To provide a substrate material having characteristics suitable to a magnetic head for attaining high recording density. A substrate material for a magnetic head comprising a matrix phase of a carbide of one or more of Ti, W and Ta and a dispersion phase of an oxide of one or more of Al.sub.2 O.sub.3, CrO.sub.3, and ZrO.sub.2, in which the material comprises 60 to 95 vol % of the matrix phase of the carbide. Further, a single phase in which the ingredients of carbides as the matrix phase comprise (Ti.sub.j W.sub.m Ta.sub.n)C.sub.x is preferred. Further, oxygen and/or nitrogen may be solid-solubilized in the carbide MeC of the matrix phase wherein Me is one or more of Ti, W, and Ta.

Abstract: This invention relates to a sintered silicon nitride ceramic material comprising:a) at least 80 wt % silicon nitride grains, andb) between 0.1 and 5 wt % additive grains characterized by at least one of:i)a Knoop hardness of at least 25 GPa,ii) a coefficient of thermal expansion of at least 6.times.10.sup.-6 /K, andiii) a modulus of elasticity of at least 600 GPa,wherein the maximum detectable grain size of the additive grains is no more than 4 um, as determined by a photomicrograph of a polished 75 mm.sup.2 microstructure of the silicon nitride material.

Abstract: A coated hard metal for a cutting tool is excellent in wear resistance and chipping resistance. The coated hard metal includes a hard coating layer on a surface of a base material of cemented carbide or cermet. The hard coating layer includes an inner layer (2) on the base material (1), an intermediate layer (3) on the inner layer (2) and an outer layer (4) on the intermediate layer (3). The inner layer (2) consists of a carbide, a nitride, a carbo-nitride, a carbo-oxide, a carbonitrogen oxide or a boronitride of Ti. The intermediate layer (3) consists of Al.sub.2 O.sub.3 or ZrO.sub.2. The outer layer (4) consists of a carbide, a nitride, a carbo-nitride, a carbo-oxide, a carbonitrogen oxide or a boronitride of Ti. The thickness of the inner layer (2) is 0.1 to 5 .mu.m, the thickness of the intermediate layer (3) is 5 to 50 .mu.m in the case of it being an Al.sub.2 O.sub.3 layer and 0.5 to 20 .mu.m in the case of it being a ZrO.sub.2 layer, and the thickness of the outer layer (4) is 5 to 100 .mu.m.

Abstract: The present invention provides for amorphous, nanoporous, ceramic material having a surface area in excess of 70 m.sup.2 /gm and characterized by a high content of open microporous cell structure wherein the micropores have a mean width of less than 20 Angstroms and wherein said microporous structure comprises a volume of greater than about 0.03 cm.sup.3 /gm of the ceramic. The invention also provides a process for the preparation of such nanoporous ceramics wherein a ceramic precursor polymer or oligomer is gradually heated in the presence of an inert gas or vacuum up to a maximum temperature in the range of greater than 400.degree. C. up to about 650.degree. C. Optionally, the process may also include a crosslinking step conducted prior to the heating step wherein the precursor polymer or oligomer is heated in the presence of a crosslinking agent capable of undergoing addition or substitution reactions with backbone atoms present in said precursor material, at an intermediate temperature of about 100.

Abstract: A process for producing high purity silicon carbide uses a high purity tetraethoxysilane or the like as the silicon source and a novolak-type phenol resin or the like as the carbon source. The process comprises a step of forming silicon carbide in which silicon carbide powder is prepared by calcining a mixture of these sources in a non-oxidizing atmosphere, and a step of post-treating silicon carbide in which the silicon carbide powder thus obtained is treated by heating at a temperature of 2000.degree. to 2100.degree. C. for 5 to 20 minutes at least once while the silicon carbide powder is kept at a temperature of 1700.degree. or higher to lower than 2000.degree. C., to obtain silicon carbide powder having an average particle diameter of 10 to 500 .mu.m and a content of impurity elements of 0.5 ppm or less. The high purity silicon carbide powder is advantageously used as a material for producing an excellent silicon carbide single crystal having a decreased number of crystal defects.

Abstract: Castable refractory for a slide gate plate is mainly formed of alumina raw material and amorphous carbon raw material of 2 to 15 wt %, and contains silicon carbide and/or boron carbide, the total content thereof being equal to 0.5 to 10 wt % (the content of boron carbide is equal to or less than 3 wt %, and when the content of boron carbide is less than 0.5 wt %, silicon carbide is set to 3 wt % or more), 2 to 10 wt % magnesia of 1 mm or less in particle size, 0.2 to 3 wt % silica fine powder of 5 micrometers or less in particle size, and 0.1 to 5 wt % salt of condensate of formalin and aromatic sulfonate.

Abstract: A mixed metal powder for hard metal alloys comprising cobalt, 1 to 10 parts per weight tungsten and 1 to 10 parts by weight of aluminum and a hard metal alloy containing the mixed metal powder binder in an amount of from 2 to 12 parts by weight per about 100 parts by weight of a metal carbide for corrosion resistant hard metal tools.

Abstract: Mesoporous desigels are fabricated as nitrides, carbides, borides, and silicides of metals, particularly transition metals, and most particularly early transition metals. The desigels are prepared by forming a gel of a metallic compound, and removing solvent from the gel. In some instances, the thus produced desigel may be further reacted to change its composition, while preserving its mesoporous structure. The materials are particularly suited as electrodes for capacitors, including ultracapacitors, and for batteries.

Abstract: A polycrystalline cubic boron nitride cutting tool is from 50 to 85% by weight cubic boron nitride crystals bonded together as a polycrystalline mass. A supporting phase commingled with the polycrystalline cubic boron nitride is made from 15 to 40% by weight of a refractory material which is preferably titanium carbonitride or titanium aluminum carbonitride. The starting composition also comprises from 4 to 10% by weight of Co.sub.2 Al.sub.9. Mixed powders of these ingredients are treated in ammonia at a temperature in the range of from 1000.degree. to 1250.degree. C., which significantly increases the nitrogen content and reduces carbon content of titanium carbonitride. Instead of mixed powders of the starting materials, coated particles may be used such as cubic boron nitride coated with titanium carbonitride, or titanium carbonitride coated with cobalt, aluminum or cobalt aluminide. Hexagonal boron nitride may be substituted as a starting material for a portion of the cubic boron nitride.

Abstract: Zirconium dioxide containing 2 to 40 vol. % of stabilizing oxides is embedded in the matrix material of a sintered molding consisting of an aluminum oxide/chromium oxide mixed crystal. The quantity of stabilizing oxides added is chosen so that the zirconium dioxide is predominantly tetragonal. The molar ratio of the zirconium dioxide containing the stabilizing oxides to the chromium oxide is between 1000:1 and 20:1 and the zirconium dioxide has a maximum particle size of 2 .mu.m.

Abstract: A hard drive disk substrate is formed of a multi-phase ceramic-based material having at least two phases with amorphous phases being present in an amount less than about 1 volume percent based on the volume of the ceramic-based material or at least one phase being free metal. A process for producing the ceramic-based disk substrate is produced by forming a flat disk of a porous ceramic and then infiltrating the porous ceramic with a metal whereby a multi-phase ceramic-based computer hard drive disk is produced. Additionally, a step of passivating the porous ceramic by elevating it to a temperature of about 1300.degree. to about 1800.degree. C. before the infiltrating step may be performed, such that the surfaces are passivated and the reaction kinetics can be controlled during the infiltrating step. A preferred composite material is made of a multi-phase boron carbide composite material including grains having peaks with an average roughness value, Ra, of between about 1 to about 200.ANG.

Abstract: The working surfaces of dental and surgical instruments are coated with a ceramic material formed by plasma spraying of a composition including a cemented carbide matrix and a ceramic dispersion to form a hardened surface with improved gripping ability. The cemented carbide matrix preferably contains tungsten and/or chromium carbide and/or cobalt. The ceramic dispersion preferably consists of alumina or other oxides.

Abstract: The present invention provides a process for preparing a molybdenum, molybdenum silicide or molybdenum carbide/ceramic admixture, comprising dissolving molybdenum trioxide powder with an alkaline solvent to obtain an aqueous solution of molybdate; incorporating ceramic powder with or without silicon and/or carbon powder into the aqueous solution of molybdate to obtain a slurry; and subjecting the slurry to spray drying and reduction to obtain the admixture. The obtained admixture can be formed and sintered into a nanometer-sized and uniformly dispersed molybdenum, molybdenum silicide or molybdenum carbide/ceramic sintered composites.

Abstract: Provided is a heat sink which has excellent processability and is economical, even though it employs diamond, as well as, a process for producing the same. The heat sink is molded using a composition obtained by adding a diamond powder of 0.1 to 100 .mu.m high-purity diamond particles to cemented carbide primarily of WC and a balance of at least one metal selected from Co, Ni and Fe along with impurities. The proportion of the diamond powder admixed relative to the cemented carbide is preferably 5 to 90%, and the diamond heat sink is produced by sintering the particulate mixture of diamond, WC, Co, etc. at a temperature of 1200.degree. to 1500.degree. C. under a pressure of 3 to 6 GPa.