Abstract: A re-usable alumina-magnesia graphite refractory suitably used for a refractory for continuous casting, such as a long nozzle used for pouring a molten metal from a ladle capable of re-use or intermittent use to a tundish, an immersion nozzle used for charging a molten metal from a tundish to a mold and a long stopper for controlling the flow rate of the molten steel; and produced by blending 3 to 60 wt % of magnesia having a particle size of 0.02 to 1.0 mm to a compound comprising mainly alumina and graphite, and kneading, molding, and baking the compound. The raw material compound comprising mainly alumina and graphite can contain spinel or zirconia.

Abstract: A ceramic matrix nanocomposite having enhanced mechanical behavior is made up of a nanotube filler composed of at least one nanotube material, and a ceramic matrix composed of a nanocrystalline ceramic oxide. A method for producing ceramic articles having improved fracture toughness includes combining of a nanotube filler made up of a nanotube material and a ceramic matrix made up of a nanocrystalline ceramic oxide, forming an article therefrom, and sintering the article under elevated pressure at elevated temperature.

Abstract: A method of forming fiber reinforced aluminum phosphate bonded material having improved strength at elevated temperatures. The method comprises the steps of: (a) preparing a slurry by blending alumina and alumina phosphate solution, the slurry being substantially free of silica; (b) providing a fiber substrate; (c) infiltrating the solution into the fiber substrate; and (d) curing the infiltrated substrate to form a fiber reinforced aluminum phosphate bonded composite material. In a preferred embodiment of the present invention, the fiber substrate is made from SiC fibers.

Abstract: A graphite-containing monolithic refractory material comprises at least one component selected from alumina and alumina-magnesia spinel, which are divided into selected particle size regions, artificial graphite having a selected average particle size, and pitch powder. The refractory material may optionally comprise a selected amount of silicon carbide having a selected average particle size. The graphite-containing monolithic refractory material exhibits excellent casting workability at a low moisture content, and both excellent corrosion resistance and spalling resistance. The refractory material is suitable as a casting monolithic refractory material for lining a topedo ladle car.

Abstract: The invention relates to a method of producing refractory compositions and more particularly to a method for producing castable refractory compositions which comprises combining appropriate quantities of bulk particulate refractory aggregates substantially without pre-mixing; separately adding to the aggregate system an appropriate quantity of a pre-blended binder composition; mixing the aggregate system and the pre-blended binder composition in a mixer; and discharging the refractory composition from the mixer.

Abstract: The invention relates to refractory waste materials and in particular to waste materials removed from furnace linings. Refractory waste materials often have hydrolysable contaminants making the material unsuitable for use in making new products. The invention provides an economical treatment process that renders such materials suitable for reuse. The process includes maintaining a particulate feedstock created from the waste material at a temperature in the range 275-500° C. and applying superheated steam to the material.

Abstract: Disclosed is a taphole plugging composition for metal melting apparatus, the composition comprising (a) a refractory aggregate having a maximum particle size of 5 mm or less, (b) graphite and silicon nitride each having a maximum particle size of 0.2 mm or less, (c) a refractory clay, (d) a compatibilized binder mixture comprising a phenolic resin, a ketone compound and a pitch, and (e) an organic fine fiber.

Abstract: A sintered material includes a polycrystalline substance of MgAl2O4 and/or Al2O3; and 3 to 90 weight percent of Cr2O3 and/or CeO2. Furnace material, furnace wall block, high temperature protection tube, and high temperature protecting member are made of such sintered material, and have higher heat resistance and corrosion resistance.

Abstract: An insulation material which is substantially free of fibers and which has a density of less than about 2.5 g/cc and a thermal conductivity of less than about 5 W/Km is formed from a composition comprising at least about 2%, by weight, carbon. The insulation material is resistant to thermal shock and is easily machined.

Abstract: There is provided a sintered silicon carbide with graphite added thereto having excellent lubrication characteristics. The sintered silicon carbide with graphite added thereto contains 10-30 wt. % of natural graphite flakes having an average grain size of 8-100 .mu.m and the remainder silicon carbide and a sintering aid, and having a relative density of 80-92%.

Abstract: Flexible graphite sheet having embedded ceramic fibers extending from its surfaces into the sheet to increase the permeability of the sheet to resin. The resin impregnated sheet is formed into a sealing gasket.

Abstract: A carbon-graphite/silicon carbide composite article is provided. The composite article includes a carbon-graphite body intimately bonded to a dense silicon carbide body by a transition/bonding region which links the two bodies. The transition/bonding region between the carbon-graphite body and the silicon carbide body typically includes a layer rich in silicon metal and a small silicon carbide/silicon metal/carbon graphite area where some of the carbon-graphite from the carbon-graphite body has been converted to silicon carbide. The carbon-graphite body may also include a variety of impregnants.

Abstract: The object of the present invention is to provide a taphole mix for use in a molten metal taphole which has improved resistance to both wear and corrosion and enables prolonged tapping of iron and reduces difficult drilling. The taphole mix of the present invention is characterized in that it comprises a refractory base material in an amount of 65 to 92 wt % and a binder in an amount of 8 to 35 wt %, the binder consisting of an anhydrous coal tar having a fixed carbon content of 32.5 wt % or above.

Abstract: Hydrofluoric acid-resistant ceramic mortar compositions containing a hydrofluoric acid-resistant grog having a particle size distribution imparting a high particle packing fraction to the mortar composition and a binding phase containing a metal salt having a particle size distribution imparting plasticity to the mortar composition selected from hydrofluoric acid-insoluble fluoride salts, metal salts capable of forming hydrofluoric acid-insoluble fluoride salts upon reaction with a fluorinating reagent and mixtures thereof. Methods for forming hydrofluoric acid-resistant ceramic mortar compositions from non-fluoride metal salts are also disclosed as well as methods for bonding refractory bricks into a brickwork unit with the ceramic mortars of the invention. Brickwork units prepared using the ceramic mortar compositions of the invention by the methods of the invention are also described.

Abstract: A refractory castable comprised of:about 45% to about 75% by weight high alumina grain;about 2% to about 35% by weight silicon carbide;about 1% to about 8% by weight carbon;about 1% to about 8% by weight calcium aluminate cement; andabout 1% to about 10% by weight fine magnesium aluminate spinel,the spinel having a grain size of less than about 150 .mu.m (100 Tyler mesh) and being comprised of about 10% to about 33% by weight magnesium oxide (MgO) and about 67% to about 90% by weight alumina (Al.sub.2 O.sub.3).

Abstract: The invention relates to refractory materials that may be used in iron and steel metallurgy comprising, in % by weight:A! 32 to 87% of particles and/or grains of at least one refractory material, the melting temperature and thermal dissociation temperature of which are greater than 1700.degree. C.;B! 7 to 50% of an in situ-formed binding matrix and consisting of a sialon, AIN or one of its polytypes, or a mixture thereof;C! 2 to 40% of a material based on titanium nitride TiN dispersed in the matrix; and, optionally,D! 0 to 42% of hexagonal boron nitride, amorphous carbon and/or crystallized graphite dispersed in the binding matrix.

Abstract: An adsorptive monolith made by extruding a mixture of activated carbon, a ceramic forming material, a flux material, and water, drying the extruded monolith, and firing the dried monolith at a temperature and for a time period sufficient to react the ceramic material together and form a ceramic matrix. The extrudable mixture may also comprise a wet binder. The monolith has a shape with at least one passage therethrough and desirably has a plurality of passages therethrough to form a honeycomb. The monolith may be dried by vacuum drying, freeze drying, or control humidity drying. The monolith is useful for removing volatile organic compounds and other chemical agents such as ozone from fluid streams. Particularly useful applications include adsorptive filters for removing ozone from xerographic devices and other appropriate office machines and volatile organic compounds from automobile engine air intake systems.

Abstract: A nozzle for continuous casting which is prevented from clogging due to alumina deposition is disclosed, wherein the inner wall member is made of a refractory material having a carbon content of 1% to 10% by weight; a material other than carbon in the refractory material has a grain size of not more than 420 .mu.m; the inner wall member is integrally molded with the outer nozzle body to form an integral structure; and said inner wall member has a thickness of 2 mm to 12 mm.

Abstract: A boron-nitride-containing material of multi-component system is obtained at a low cost by heating a mixed powder containing a boride and an oxide in a nitrifying atmosphere, whereby a part or the whole of the oxide is reduced with the element bonded to boron of the boride to convert the raw materials to one or more kinds of an oxide having less bonded oxygen, an acid nitride, a nitride, a carbide, and a boride and also boron nitride is formed. A sintered product of a boron-nitride-containing material is obtained by packing a mixed powder containing borides in a heat-resistant mold and heating the packed powders in a nitrifying atmosphere while restraining the packed powders by the mold. The sintered product is obtained in which neither expansion nor deformation occurred and no cracks formed.

Abstract: Disclosed is a monolithic refractory comprising 1 to 30 weight parts of pitch having 65 to 90 wt.-% of fixed carbon and a softening point of 250.degree. to 350.degree. C. to form a carbon bond, relative to 100 weight parts of refractory material so as to form carbon bond. The monolithic refractory can contain 0.01 to 0.5 weight parts of carbon fiber. The composition of the invention may be used as any type of monolithic refractory such as gunning material, casting material, in particular, aqueous type casting material, burning type hot repairing mix, mortar, Tamping material, and any basic, neutral, or acid refractory material may be used. The monolithic refractory is capable of solving the drawbacks of the conventional monolithic refractories such as rupture, lack of low shrinkage, low bonding strength, low hot strength, and having both superior strength and superior applicability.

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 refractory article of manufacture comprises an article of graphite-alumina refractory material coated with at least one mineral having a sheet structure and a refractory oxide bond. The coating protects the article against thermal shock. A typical mineral having a sheet structure may be talc, a mica, vermiculite, antigorite, kaolinite, montmorillonite, pyrophyllite, or combinations of these materials. A typical refractory oxide bond is formed from alumina gel, silica sol, alumina sol, zirconia sol, or combinations of these materials (such as a combination of alumina gel and cationic silica sol). The coating may also contain a minor proportion of fibrous material and a minor proportion of particulate refractory filler other than the mineral having a sheet structure, and a portion of the mineral content of the mineral forming the sheet structure may include graphite.

Abstract: A glass material of the invention contains SiO.sub.2, MgO, Al.sub.2 O.sub.3, and TiO.sub.2 as main components in amounts of 40-65% by weight of SiO.sub.2, 9-30% by weight of MgO, 8-31% by weight of Al.sub.2 O.sub.3, and 6-15% by weight of TiO.sub.2, and satisfies expression I: {100-(A+S+T)}/S.gtoreq.0.340 wherein A, S and T are contents in % by weight of Al.sub.2 O.sub.3, SiO.sub.2, and TiO.sub.2, respectively, and Expression II: (S+M)/4>100-(S+M+A+T) wherein M is a content in % by weight of MgO, and is substantially free of fluorine. It is used in the preparation of a living tissue replacement or orthodontic part. A living tissue replacement and orthodontic part which experience a minimal loss of material properties in a deleterious environment as in the oral cavity and should have a complex shape as in the case of a dental crown repair, high strength and aesthetic appearance can be briefly prepared in a safe manner without using a special manufacturing apparatus.

Abstract: A spray operation method for monolithic refractories, which comprises forcibly sending to an application field by a force feed pump and a force feed piping a self flowable mixed batch prepared by mixing, together with water, a powder composition for monolithic refractories comprising refractory aggregates, a refractory powder and a small amount of a dispersant; injecting into the mixed batch, compressed air and a required amount of a rapid setting agent respectively from a compressed air injection inlet and a rapid setting agent injection inlet provided at a downstream portion or downstream portions of the force feed piping; sending the mixed batch together with the compressed air by a nozzle piping to a spray nozzle attached to the forward end of the nozzle piping; and spraying the mixed batch from the spray nozzle to an application site.

Abstract: Alumina composites of unusually high hardness and toughness are formed by combining alumina and diamond in nanocrystalline form, followed by sintering at high pressure.

Abstract: The invention concerns a component for the pouring of steel that has a body (2) of a refractory material containing carbon. It has a layer (10) that covers the body partially or completely and is capable of forming a surface layer (10a) that is oxidized and densified and is impermeable to gases when it is brought to a temperature above 1000.degree. C. The layer (10) is comprised of a refractory material containing sintering precursors chosen in the group consisting of calcined alumina, reactive calcined alumina, silica fumes and clays.

Abstract: Provided is a refractory for casting which contains clinker having a mineral crystal phase consisting essentially of mullite and baddeleyite. The refractory for casting has excellent in a thermal-shock resistance, corrosion resistance and strength. The refractory for casting is manufactured from a raw material containing a refractory composition and an organic binder, wherein the refractory composition comprises(a) 3 to 60 wt % of clinker having a mineral crystal phase consisting essentially of mullite and baddeleyite, and containing 5 to 22 wt % of alumina (Al.sub.2 O.sub.3), 38 to 68 wt % of zirconia (ZrO.sub.2) and 27 to 40 wt % of silica;(b) 5 to 40 wt % of at least one carbon-based material selected from the group consisting of graphite and carbon; and(c) at least one refractory element as a balance, selected from the group consisting of alumina, fused silica, zirconia, silicon carbide, mullite and a metal silicon.

Abstract: A dense carbon free surface is provided on a carbon bonded refractory shape which is particularly useful as a pouring tube liner to prevent the formation and build-up of alumina particles which may cause blockage of the tube. The carbon free, dense layer is also hard and erosion resistant making it ideal for use in other applications such as stopper rod noses. The material comprises a refractory mix having a major component of refractory oxides such as alumina and zirconia-mullite. Less than 10 wt. % carbon in the form of graphite and binder is in the mix plus about 2-5 wt. % of a metal such as silicon and an effective mount of sintering aids is also present. The pressed shape is preheated to a temperature of 1000.degree. -1400.degree. C. in air to oxidize the exposed surface of the shape and then to sinter the oxidized surface to form the desired dense, carbon free surface over the entire shape or on selected surface portions thereof.

Abstract: The present invention pertains to an electrically conductive, dry, refractory ceramic mass based on a refractory oxidic matrix material containing a source of carbon, such as graphite, carbon black or petroleum coke.

Abstract: The invention discloses a long carbon fibre reinforced ceramic matrix composite in which the matrix is an engineering ceramic, characterized in that the engineering ceramic comprises Al.sub.2 O.sub.3 and Y.sub.2 O.sub.3 as highly refractory sinter additives, the composite has a high density of at least 95% theoretical, a high fibre content of at least 30% by volume, and that substantially all the fibres are uniformly distributed within the matrix with a uniform inter-fibre spacing of 10-15 micrometer. The invention also discloses a process for preparing such a composite, characterized in that unidirectionally wound fibre tapes are cut into sections, the sections are infiltrated by the matrix material in the form of a slurry of the ceramic itself or as a precursor material, the infiltrated fibre tape sections are successively stacked and pressed wet to achieve intermeshing of the tape sections, compacted, dried and hot pressed.

Abstract: A self-sintered silicon carbide/carbon-graphite composite material having interconnected pores which may be impregnated, and a raw batch and process for producing the composite material, is provided. The composite material comprises a densified, self-sintered matrix of silicon carbide, carbon-graphite inclusions and small amounts of any residual sintering aids, such as boron and free carbon, and has interconnected pores which may be impregnated with resin, carbon, TEFLON, metal or other compounds or materials selected for their particular properties to achieve desired tribological characteristics for a specific application. The composite material is produced from a raw batch which includes silicon carbide, sintering aids, a temporary filler and coated graphite particles. The raw batch is then molded/shaped into a green body and heated to carbonize any carbonizable materials and to decompose and volatilize the organic filler to form a matrix of interconnected pores.

Abstract: An artificial coarse-grain aggregate with particle size of 1-5 mm is prepared by adding alumina particulates as an agent for preventing molten iron erosion, metallic silicon particulates as a pore-size reducing agent, and organic binder to flake graphite with high thermal conductivity or to artificial graphite with particle size of 1 mm or less or to a mixture of both types of graphite, and then by kneading, molding, baking, crushing, and screening. By compounding the coarse-grain aggregate thus manufactured instead of the conventional coarse-grain aggregate of calcined anthracite, artificial graphite, or flake graphite to manufacture carbon refractories, large-sized carbon refractories for blast furnaces, with high thermal conductivity and resistance to molten iron, may be manufactured at high yields. In result, the obtained carbon refractories are favorable as lining material for the basin parts of blast furnaces.

Abstract: A process is described for the production of alumina/zirconia materials which uses cheap scrap alumina/zirconia/silica material as feedstock along with a reducing agent to lower the final silica content to an acceptable level.

Abstract: Chrome-free bricks which exhibit excellent resistance to corrosion, penetration, and thermal spalling. The bricks are mainly made from a magnesia material and/or a magnesia-alumina spinel material and comprise 1 to 10 wt % titania and 1 to 15 wt % alumina. They may contain 0.5 to 10 wt % iron oxide. Further, they may contain at least one material of the group consisting of 1 to 10 wt % metal powder, 1 to 20 wt % carbon and 1 to 20 wt % one of oxide materials except for iron oxide.

Abstract: A slurry for joining metallic or ceramic surfaces or for coating metallic or ceramic and refractory surfaces, comprising a liquid suspending medium and at least two constituents in particulate form suspended in the medium, the constituents being so selected and proportioned as to undergo combustion synthesis when ignited. A method for coating or joining metallic or ceramic surfaces comprises applying such a slurry to a surface to be coated or to surfaces to be joined, and igniting the slurry to cause combustion synthesis.

Abstract: A magnesite-carbon refractory mix for forming refractory shapes containing magnesite, graphite, and a fine particle size metallic additive consisting essentially of a magnesium-aluminum alloy co-milled with magnesite and refractory shapes and refractory linings made therefrom.

Abstract: A method of treating a water-swellable clay after the clay has been mined and dried to improve its properties when in contact with salt-contaminated water. After the common initial drying of the clay to a moisture content of 12% by weight or less, the clay is rewetted to a moisture content of more than 12% by weight, preferably at least about 15% or more, based on the dry weight of the clay, then redried to a moisture content of 12% by weight or less, based on the dry weight of the clay.

Abstract: A dense, self-sintered silicon carbide/carbon-graphite composite material and a process for producing the composite material is disclosed. The composite material comprises a silicon carbide matrix, between 2 and 30 percent by weight carbon-graphite, and small amounts of sintering aids such as boron and free carbon. The silicon carbide has an average grain size between 2 and 15 .mu.m, and the carbon-graphite has an average grain size between 10 and 75 .mu.m, the average grain size of the carbon-graphite being greater than the average grain size of the silicon carbide. The composite material has a density of at least 80 percent of theoretical density as determined by the rule of mixtures for a composite material. This density is achieved with minimal microcracking at a high graphite loading with large graphite particles. The composite material exhibits good lubricity and wear characteristics, resulting in improved tribological performance.

Abstract: A granular castable refractory composition is provided which has excellent insulating properties as well as high strength and resistance to oxidation, corrosion or erosion. The refractory insulating composition can be easily transported using a pump, and avoids the potential hazards associated with asbestos and ceramic fibers. The refractory insulating composition is prepared by mixing a low density expanded granular refractory insulating material having a density of 7-50 lb/ft.sup.3 with a conventional high density refractory material having a density of at least 150 lb/ft.sup.3 to form a dry component, and by mixing the dry component with aqueous colloidal silica to provide excellent flow properties for pumping and, ultimately, excellent binding properties.

Abstract: A refractory article such as a slide gate plate, well block nozzle or like refractory component used in continuous casting of chemically aggressive grades of steel is made from a mixture containing about 50-85 wt. % alumina; about 5-30 wt. % alumina-zirconia fused grain; about 3-10 wt. % zirconia; and about 3-10 wt. % silica, plus an effective amount of binder materials to permit extrusion, pressing or like forming process. The pressed shape is fired in an air atmosphere at temperatures in excess of 1000.degree. C. to form an oxide bond. The composition of the fired material comprises about 60-90 wt. % alumina; about 5-30 wt. % zirconia; and about 3-10 wt. % silica. The fired article exhibits excellent hot strength and is resistant to thermal shock and resistant to the erosive and corrosive effects of molten steel, including aggressive, high manganese and calcium treated grades.

Abstract: Ceramic precursor materials bound together by a product of a condensation reaction between a first reactant that has at least one reactive hydroxyl moiety, such as a carbohydrate, and a second reactant that has at least one reactive nitrogen-containing moiety, such as melamine, and dried or dried and calcined, form porous aggregates that resist crushing or disintegration during processing through various reactor apparatus.

Abstract: There are disclosed a process for producing a uniformly mixed composite raw material for ceramics by recovering the uniformly mixed composite raw material for ceramics from the dispersion of at least two types of raw materials for ceramics and optionally a component other than said materials in a liquid medium, which comprises coagulating and precipitating the composite raw material together with aluminum hydroxide formed by reacting an aluminum salt with an alkali in the liquid medium; and a uniformly mixed composite raw material for ceramics which is produced by the above process.

Abstract: A composition comprising leonardite, clay, lime, and an inorganic salt mixture and a process for controlling air quality comprising contacting an air stream with the composition are provided wherein the composition supports microbial growth. The inorganic salt mixture comprises a nitrogen source and a phosphorus source. The air stream generally contains at least one volatile organic compound.

Abstract: Carbon fiber reinforced silicon nitride based nanocomposite material is produced by mixing a powder mixture of silicon nitride powders (with or without alumina powders), and fine silicon carbide powders, with a solution of a preceramic polymer containing silicon and nitrogen, to form a solution for impregnation, by passing carbon fibers through the solution to produce a mass of impregnated carbon fibers, forming the mass to a desired shape and by sintering in an inert atmosphere. Ultra-high strength and toughness are produced due to reinforcement by nanocompositization of the matrix phase, that by dispersion of fine particles and that by long carbon fibers, part of matrix phase is generated by thermal cracking of preceramic polymer.

Abstract: A fired carbon-bonded, oxide refractory body for use in casting aluminum-killed steel has a metal contacting surface which is resistant to both steel erosion and buildup of alumina. The layer is formed by first firing the pressed body in an oxidizing atmosphere to form a porous oxidized zone on selected steel contacting surfaces. The remaining surface portions of the body are protected against oxidation during firing by a glaze applied prior to firing. A carbon free refractory slip or slurry is infiltrated into the porous oxidized zone to create the erosion and buildup resistant surface layer. A preferred infiltrant material is alumina.

Abstract: Improved gunnable plastic refractory compositions consist of a mass of friable clusters of granular material which has a moisture content of from about 4% to about 10% by weight of the total composition and contains from about 0.05% to about 0.5% by weight (added), preferably 0.1% to 0.3%, of a hydrocolloid selected from the class consisting of a polysaccharide ether and xanthan gum and from about 0.05% to about 1.0% by weight (added), preferably 0.15% to about 0.50%, carbon.

Abstract: A process for producing a substantially non-explosive powder containing finely divided metallic particles suitable for being incorporated in a refractory mixture, comprising simultaneously grinding a mixture of pieces of metal with pieces of an inert refractory material to produce a premixture containing finely divided metallic particles and finely divided refractory particles which are intimately mixed together. The refractory particles are present in such particle sizes and quantities as ensure that the Minimum Explosible Concentration, as tested in a 20-L vessel with a chemical igniter, is greater than 100 gm/m.sup.3. The inert particles comprise at least 40% of the mixture, and preferably 50% to 75%. The invention also includes a premixed powder, produced by this process, especially as contained in drums or impermeable bags.

Abstract: The present invention pertains to a binding and plasticizing agent for preparing refractory materials, in which the binding agent contains a synthetic resin, a phosphate, and a surface-active agent.

Abstract: Carbon-containing carbon bonded refractory mixes and products made therefrom in which the refractory is a magnesite or high alumina aggregate and containing a silica-free elemental boron containing B-Mg-O alloy powder containing at least 95% B-Mg-O. and shapes made therefrom. The invention also involves the method of increasing the lining life of a metallurgical vessel utilizing unburned brick made from the above-noted mixes.

Abstract: A heat conductive aluminum nitride sintered body contains 100 parts by weight of aluminum nitride, at least 0.005 parts by weight and not more than 0.5 parts by weight of carbon, at least 0.01 parts by weight and not more than 15 parts by weight of a rare earth aluminum oxide in terms of the simple substance of a rare earth element, and at least 0.01 parts by weight and not more than 15 parts by weight of at least one element selected from a group of compounds containing elements belonging to the groups IVB, VB and VIB of the periodic table in terms of the simple substance of the element. Such a sintered body has a heat conductivity of at least 100 W/m.multidot.K. and not more than 270 W/m.multidot.K. at room temperature.