Abstract: An SiC-based pressureless sintered product contains a sintered product main component containing grains of at least one additive selected from the group consisting of Tac, NbB.sub.2, VB.sub.2 and WB and the balance of SiC sintered grains constituting a SiC matrix, and a sintering assistant component. The additive grains have a maximum grain size not greater than an average grain size of the SiC sintered grains.

Abstract: A method of preparing preceramic SiC fibers having a very low oxygen content by forming fibers from a solution of a polycarbosilane and a vinylic SiC precursor in a mutual volatile solvent, heating fibers in an oxygen-free inert atmosphere to effect a cross-linking reaction therebetween. Also disclosed is a method of preparing SiC fibers having superior high temperature properties and a very low oxygen content comprising heating the above-described cross-linked preceramic fibers in an inert atmosphere substantially free of oxygen for a time and at a temperature sufficient to pyrolyze the cross-linked fibers to SiC fibers. The disclosure also describes the novel fibers produced by the above-described methods.

Abstract: The processes of the invention involve the formation of an initial reactant mixture by combining sources of SiO.sub.2, B.sub.2 O.sub.3, aluminum, and carbon. The mixture may then optionally be shaped or compacted. The reactant mixture is then heated to start a reaction which is described by the formula:4 C+3 SiO.sub.2 +2 B.sub.2 O.sub.3 +8 Al.fwdarw.4 Al.sub.2 O.sub.3 +B.sub.4 C+3 SiC.Depending on the actual reactant mixture compositions and reaction conditions, other reactions may also occur.

Abstract: This invention relates to the preparation of highly densified ceramic bodies by the pyrolysis of a mixture comprising a preceramic borosilazane, silicon carbide powder, and, optionally, a curing agent for the borosilazane. Such highly densified ceramic bodies can be prepared by sintering under pressure or by a pressureless sintering process.

Abstract: An improved gunning composition for use in the steel industry includes between 60-75% by weight of a refractory base material, 10-20% by weight of silicon carbide, 7-15% by weight of ball clay, 4-8% by weight of a silica binder material, and, optionally, 5-10% by weight of a graphite material. The silica binder replaces binders composed of petroleum pitch or clay. The silica binder causes the composition to have (1) better adhesion, (2) less cracking, (3) improved strength, and (4) increased resistance to oxidation, corrosion and erosion.

Abstract: Substantially dense, void-free ceramic-metal composites are prepared from components characterized by chemical incompatibility and non-wetting behavior. The composites have a final chemistry similar to the starting chemistry and microstructures characterized by ceamic grains similar in size to the starting powder and the presence of metal phase. A method for producing the composites requires forming a homogeneous mixture of ceramic-metal, heating the mixture to a temperature that approximates but is below the temperature at which the metal begins to flow and pressing the mixture at such pressure that compaction and densification of the mixture occurs and an induced temperature spike occurs that exceeds the flowing temperature of the metal such that the mixture is further compacted and densified. The temperature spike and duration thereof remains below that at which significant reaction between metal and ceramic occurs. The method requires pressures of 60-250 kpsi employed at a rate of 5-250 kpsi/second.

Abstract: A drill bit of a diamond-coated sintered body has a substrate mainly composed of Si.sub.3 N.sub.4 or SiC. At least a wear portion of the bit is coated with a diamond layer. If the bit is of the throw-away kind, an insert is removably secured to a shank. At least the insert or a wear portion thereof is coated with a diamond layer. The sintered body contains a prescribed amount of a sintering assistant or aid selected from MgO, Y.sub.2 O.sub.3 and the like. The diamond coating layer has a thickness of at least 0.1 .mu.m.

Abstract: This invention provides a carbon-containing ceramic composite for molten non-ferrous metal, the composite being a sintered ceramic body to be used in contact with molten non-ferrous metal, the sintered body containing an aggregate of silicon carbide and/or silicone nitride, the sintered body being characterized in that it comprises,(a) 100 parts by weight of the aggregate,(b) 5 to 45 parts by weight of flake graphite, and(c) boron carbide in an amount of 10 to 40% by weight based on the flake graphite.

Abstract: This invention relates to the preparation of highly densified ceramic bodies by the pyrolysis of a mixture comprising a preceramic borosiloxane, silicon carbide powder, a curing agent for the borosiloxane, a crosslinking agent for the borosiloxane and, optionally, additional components to facilitate sintering. Such highly densified ceramic bodies can be prepared by sintering under pressure or by a pressureless sintering process.

Abstract: Disclosed is a sintered silicon carbide body with a high thermal conductivity which has a thermal conductivity of not less than 150 W/m.multidot.K, which is produced by(a) mixing(1) a first silicon carbide powder having a mean grain size of from 0.1 to 10 .mu.m with(2) a second silicon carbide powder having a mean grain size of not greater than 0.1 .mu.m prepared by(2-1) introducing a starting gas composed of a silane compound or silicon halide and a hydrocarbon into a plasma of a non-oxidative atmosphere, and(2-2) conducting gas phase reaction between the silane compound or silicon halide and the hydrocarbon while controlling the pressure of the reaction system within the range of from less than 1 atom to 0.1 torr, and(3) optionally, a carbon powder which is required for reducing oxides contained in both the first and second silicon carbide powders,(b) optioanlly reducing the oxides with the carbon, and(c) heating the resulting mixture for sintering. Also, processes of producing the same are disclosed.

Abstract: Disclosed is an electrically conductive sintered silicon carbide body having an electric resistivity of not higher than 1 .OMEGA..multidot.cm, which is produced by(a) mixing(1) a first silicon carbide powder having a mean grain size of from 0.1 to 10 .mu.m with(2) a second silicon carbide powder having a mean grain size of not greater than 0.1 .mu.m prepared by(2-1) introducing a starting gas composed of a silane compound of silicon halide and a hydrocarbon into a plasma of a non-oxidative atmosphere, and(2-2) conducting gas phase reaction between the silane compound or silicon halide and the hydrocarbon while controlling the pressure of the reaction system within the range of from less than 1 atom to 0.1 torr, and(3) optionally, a carbon powder which is required for reducing oxides contained in both the first and second silicon carbide powders,(b) optionally reducing the oxides with the carbon, and(c) heating the resulting mixture for sintering. Also, processes of producing the same are disclosed.

Abstract: Disclosed herein is a slider of which sliding performance, i.e., sealing performance is improved, without decline of combination strength of grain boundaries and abrasion resistance, by including 2-10%, more preferably 3-8% by weight of free carbon in a slider composed of a high density silicon carbide sintered compact of which relative density is not less than 95%.

Abstract: The process comprises the steps of forming a fibrous reinforcement with silicium carbide fibers, forming on the fibers an intermediate coating designed to constitute an interface between the fibers and a matrix, and forming a matrix in ceramic material within the residual porosity of the fibrous reinforcement. In a step prior to the formation of the intermediate coating, a treatment is carried out by the chemical route for the elimination of the silica present on the surface of the silicium carbide fibers.

Abstract: In the production of silicon carbide, a starting composition comprising silicon dioxide powder and a carbonaceous substance and having a bulk density of 0.2 to 2.0 g/cm.sup.3 is used, wherein the silicon dioxide is covered with the carbonaceous substance and uniformly dispersed therein. The starting composition is produced by forming a kneaded mixture of silicon dioxide and high molecular weight organic compound, heating the kneaded mixture to conduct carbonization and thereby form a composite body and then granulating the composite body into 3 to 25 mm sized granules.

Abstract: An improved ramming composition for use in the iron and steel industry includes between 65-80% by weight mullite, 5-15% by weight silicon carbide, 2-5% by weight graphite, 2-6% by weight ball clay, and 5-10% by weight of a binder formed from a dispersion of 15-70% by weight silica in water. The silica binder replaces binders composed of petroleum pitch, clay, or other organic materials. The silica binder causes the ramming composition to have a longer use life, increased strength, and reduced tendency to crack, oxidize or smoke.

Abstract: The present invention provides fiber-reinforced ceramics containing at least one member of fibers and whiskers as distributed in a sintering ceramic matrix, which comprises the ceramic matrix being composed mainly of SiC, Si.sub.3 N.sub.4 and Si.sub.6-z Al.sub.z O.sub.z N.sub.8-z, where 0<z.ltoreq.4, the fibers and the whiskers being composed of at least one of SiC, Si.sub.3 N.sub.4 and Si.sub.6-z Al.sub.z O.sub.z N.sub.8-z, where 0<z.ltoreq.4, and a coating film of C, B or BN being provided on the surfaces of the fibers and the whiskers. The fiber-reinforced ceramics have a high fracture toughness, K.sub.1c, and a high bending strength, particularly K.sub.1c of at least 10 MN/m.sup.3/2 and a bending strength of at least 50 kg/mm.sup.2.

Abstract: The present invention provides fiber-reinforced ceramics containing at least one member of fibers and whiskers as distributed in a sintering ceramic matrix, which comprises the ceramic matrix being composed mainly of SiC, Si.sub.3 N.sub.4 and Si.sub.6-z Al.sub.z O.sub.z N.sub.8-z, where 0<z.ltoreq.4, the fibers and the whiskers being composed of at least one of SiC, Si.sub.3 N.sub.4 and Si.sub.6-z Al.sub.z O.sub.z N.sub.8-z, where 0<z.ltoreq.4, and a coating film of C, B or BN being provided on the surfaces of the fibers and the whiskers. The fiber-reinforced ceramics have a high fracture toughness, K.sub.lc, and a high bending strength, particularly k.sub.lc of at least 10 MN/m.sup.3/2 and a bending strength of at least 50 kg/mm.sup.2.

Abstract: A method for producing sintered shapes of refractory powders with improved strength and toughness using a grain growth inhibiting powder to inhibit grain growth.

Abstract: Boron nitride is coated on filaments of elemental carbon and/or silicon carbide, the coated filaments are contacted with an infiltration-promoting material containing elemental carbon to produce a preform wherein the filaments are substantially parallel and each filament is enveloped with infiltration-promoting material, and the preform is infiltrated with a molten solution of boron and silicon producing a composite containing boron nitride coated filaments.

Abstract: A composite material comprises silicon carbide and a boride of at least one element of Groups IVa to VIa of the Periodic Table, at least a portion of the boride being in the form of fiber having an aspect ratio of 3 or above. The composite material has high toughness owing to the fibrous boride.The composite material is produced by molding a raw material mixture composed of silicon carbide, a substance containing at least one element of Groups IVa to VIa of the Periodic Table, at least a portion thereof being in the form of fiber having an aspect ratio of 3 or above, and a substance containing boron, and sintering the molded body.

Abstract: A sintered article of diamond is obtained by coating the surface of diamond particles with 30 to 0.1% by volume, based on the total volume of the diamond particles and aids, of at least one member selected from the group consisting of the transition metals of Groups 4a, 5a, and 6a in the Periodic Table of Elements and boron and silicon, and sintering the coated diamond particles under conditions of high pressure and high temperature, which sintered article consists of 70 to 99.8% by volume of diamond and 30 to 0.2% by volume of the carbide of the coating substance. A method for the production of the sintered article of diamond is also disclosed.

Abstract: Fibrous material is coated with boron nitride and a silicon-wettable material, the coated fibrous material is admixed with an infiltration-promoting material which is at least partly elemental carbon and the mixture is formed into a preform which is infiltrated with a molten solution of boron and silicon producing a composite containing boron nitride coated fibrous material.

Abstract: A forming aid to be mixed in a ceramic material for forming the ceramic material into a formed ceramic body of a desired shape, including at least one of a thermoplastic resin and a wax, and a mineral oil in an amount of 30-95% by volume with respect to an entire volume of the aid. Also disclosed is a process of producing a ceramic article from the formed ceramic body containing the aid.

Abstract: A ceramic body of controlled porosity is formed by coating unidirectional fiber carriers with a hardenable liquid resin bearing powdered ceramic material, which resin is subsequently cured, hardened, or cooled to provide a green body which may be assembled with similar layers, in a desired shape, and subsequently sintered, to form a ceramic body having continuous pores corresponding to the position of the fibers.

Abstract: A siliconized graphite for use in mechanical seals is provided. This material is prepared by reacting graphite at an elevated temperature ranging from 1800.degree. to 2100.degree. C. with silicon monoxide. Silicon monoxide is generated in rate-controlled fashion by reacting either silicon carbide and silica or silicon nitride and silica at an elevated temperature ranging from 1500.degree. to 1800.degree. C.Although the optimum temperature range for the SiO generation and the siliconization of graphite is different by 300.degree. C., size-controlled raw materials (silicon carbide, silicon nitride, and silica) and a unique sample loading method make the whole process occurred in situ and make the production of mechanical seals efficient. Size-controlling of the raw materials is essential for a constant supply of silicon monoxide in controlled fashion, and a unique sample loading method is essential to put the SiO generation and the siliconization of graphite within their optimum temperature ranges.

Abstract: A process for producing a diamond compact comprised of diamond crystals bonded mainly by silicon carbide. The diamond crystals are intimately mixed with silicon in the proportions 97 to 65 percent by weight of diamond to 3 to 35 percent by weight of silicon. The thus-mixed diamond crystals and silicon are placed immediately adjacent to one or more bodies of silicon within a container and subjected to high pressure and temperature so as to cause melting of the premixed silicon and of the external silicon which infiltrates into the interstitial spaces between the diamond crystals to cause most of the silicon between the diamond crystals to react with diamond to produce silicon carbide. The elevated temperature is in the range 1,100.degree. to 18,000.degree. C., and the elevated pressure is in the range 10 to 40 kilobars. The resulting compact contains between 50 and 85 volume percent of diamond with a density of at least 3.35 g/cm.sup.3 and a compressive strength of at least 10 kilobars.

Abstract: A method of bonding metallic wires, such as strain gages, thermocouples, etc., directly onto ceramic components, such as silicon nitride or silicon carbide turbine parts, by means of a refractory cement formed from a mixture of water, sodium silicate, and a ceramic powder, preferably of a composition similar to the underlying ceramic component. Several thin layers of the mixture are applied and cured so as to provide a strong bond having good thermal shock resistance for testing at typical gas turbine operating temperatures, such as 2500.degree. F. or above.

Abstract: A porous form body is produced of sinterable SiC-powder by forming a suitable suspension of said SiC-powder and then treating the suspension to convert it into droplets and the droplets into a granular material in which the granules are substantially larger than the particles of SiC-powder. The granular material is then formed into a green body, e.g. by spraying the granules onto a negative mold of the form body or slip-casting or the like. The green body is then sintered whereby the resulting porosity in the final form body provides the form body with low drag.

Abstract: The invention relates to a method for producing a sintered silicon carbide article having a sintered density of at least 90% of the theoretical density and a mechanical flexural strength of 50 kg/mm.sup.2 or higher. This is achieved by adding to a finely divided .alpha.-type silicon carbide powder, a tar pitch in such amounts as to provide 4.2-6 parts by weight of carbon after carbonization and a boron compound such as to correspond to a boron content of 0.005-0.15 parts by weight as densification aids, mixing and shaping the resulting mixture, and then sintering the thus-shaped article in an inert atmosphere at a temperature of from 1950 .degree. to 2300.degree. C.

Abstract: A process of forming a coherent refractory mass on a surface comprises projecting against that surface, together with oxygen, a mixture of refractory particles and fuel which reacts in an exothermic manner with the projected oxygen to release sufficient heat to melt at least the surfaces of the refractory particles and thus form the refractory mass. The projected mixture contains, as fuel, finely divided particles of at least one element which is oxidizable to form a refractory oxide and it also contains carbonaceous particles which are of such a size or composition that carbon particles become occluded in the formed refractory mass. The mixture may contain, as said fuel, finely divided particles having a mean grain size of less than 50 .mu.m of silicon, aluminum and/or magnesium. The carbonaceous particles may comprise a carbonaceous core which is covered by a mantle inhibiting oxidation of the core.

Abstract: A slider, the sliding performance, i.e., sealing performance of which is improved, without a decline in the combination strength of the grain boundaries and the abrasion resistance, by including 2-10%, more preferably 3-8%, by weight of free carbon in a slider composed of a high density silicon carbide sintered compact the relative density of which is not less than 95%.

Abstract: A carbon-containing refractory is formed by mixing 1-10 weight % of silicon nitride, 1-35 weight % of carbon, and a remainder of a refractory raw material, molding the mixture into a molded body, and burning the molded body such that fine whiskers of silicon carbide are uniformly distributed within the matrix.

Abstract: A high density SiC sintered body can be obtained by molding a mixture of two kinds of high temperature-type and low temperature-type silicon carbides together with sintering aids into a shaped article, primarily firing the shaped article, and subjecting the primarily sintered body to an HIP treatment.

Abstract: A process for producing reinforced cementitious compositions in which the following constituents are mixed in the aqueous phase in the following order: about 35-55 parts by weight of water mixed with about 3-12 parts of a polymer, by weight of dry polymer; up to about 5 parts of a water-reducing auxiliary agent and/or a liquifying agent; from about 15-30 parts of metakaolin; from about 50-120 parts of silica sand; and about 100 parts of cement. Continuous mixing is maintained until a homogeneous, thixotropic paste is obtained. Then between 2 and 15% by weight of alkaline-resistant glass fibers, relative to the weight of the paste, is introduced into the paste. The product produced by this method is particularly suitable for use as a mortar or paste which may be easily sprayed upon vertical surfaces and as hydraulic concretes, resistant to the effects of weather and aging.

Abstract: A silicon carbide complex sintered body including 20 to 99 wt % of SiC, 80 to 0.5 wt % of at least one compound selected from the group consisting of W.sub.2 B.sub.5 and/or MoB.sub.2, and 0.5 to 5 wt % of at least one material selected from the group consisting of boron, carbon, and boron carbide. A process for producing the sintered body by preparing a mixed powder is also disclosed, wherein the mixed powder includes 20 to 99 wt % of SiC powder having an average particle diameter of not greater than 5 microns, 80 to 0.5 wt % of at least one compound selected from the group consisting of W.sub.2 B.sub.5 and MoB.sub.2, and 0.1 to 5 wt %, when calculated as boron, of boron or a compound containing boron, and 0.1 to 5 wt %, when calculated as carbon, molding the mixture, and firing the molding in a temperature range from 1,900.degree. to 2,500.degree. C. in vacuum or in an inert atmosphere.

Abstract: The preparation of highly densified ceramic bodies by the sintering of certain preceramic polysilazanes filled with silicon carbide powders, metal-containing sintering aids, and, optionally, polysilazane curing agents is described. Such highly densified ceramic bodies can be prepared by either a pressureless sintering process or a hot press sintering process. The compositions of this invention can be formed into desired shapes and then sintered to form ceramic, shaped bodies with high densities. One advantage of the present invention is that the green bodies have relative high strengths and thus can be easily handled and, if desired, machined before sintering. The preceramic polysilazanes useful in this invention must yield ceramic chars which contains free or excess carbon in addition to carbon in the form of silicon carbide upon pyrolysis to elevated temperatures.

Abstract: A bonding composition for silicon carbide ceramics, comprising: silicon carbide powder having a particle size of 1 to 50 .mu.m, powder carbon having a particle size of up to 15 .mu.m, silicon powder having a particle size of up to 10 .mu.m, a thermosetting resin, and a catalytically curable resin and a curing agent therefor. The composition is effective in bonding sintered silicon carbide ceramic pieces.

Abstract: Preceramic molding compositions capable of forming low density ceramics having acceptable strength and improved wear resistance are compositions having a particle size not larger than about 105 micrometers and comprising an intimate mixture of (A) about 50-90 parts by weight of powder ingredients comprising about 2-50% by weight of graphite powder and about 98-50% by weight of a second powder selected from silicon carbide, silicon nitride, and mixtures thereof and (B) correspondingly, about 50-10 parts by weight of a preceramic polysilazane binder.

Abstract: The preparation of highly densified ceramic bodies by the sintering of certain organopolysiloxanes filled with silicon carbide powders, and metal-containing sintering aids is described. Such highly densified ceramic bodies can be prepared by either a pressureless sintering process or a hot press sintering process. The compositions of this invention can be formed into desired shapes and then sintered to form ceramic, shaped bodies with high densities. One advantage of the present invention is that the green bodies have relative high strengths and thus can be easily handles and, if desired, machined before sintered. The organopolysiloxanes useful in this invention must yield a ceramic char which contains free or excess carbon in addition to carbon in the form of silicon carbide upon pyrolysis to elevated temperatures.

Abstract: A high-toughness silicon carbide composite ceramic comprising silicon carbide, 5 to 50 vol % of graphite whiskers, and sintering aid, and a method for producing the composite ceramic. The composite ceramic has high-temperature strength and fracture toughness value, and also has electrical conductivity.

Abstract: In processes of forming a refractory mass on a surface, a mixture of refractory particles and oxidizable particles which react exothermically with oxygen to generate sufficient heat to soften or melt at least the surfaces of the refractory particles are sprayed against that surface to bring about formation of said refractory mass. To promote the reliable and consistent formation of a durable refractory mass, the granulometry of the particles which are sprayed in the mixture is such that the 80% and 20% grain sizes of the refractory particles (that is, the screen mesh sizes G.sub.80 and G.sub.20 through which respectively 80% and 20% by weight of the particles will pass) have a mean greater than the mean of the 80% and 20% grain sizes of the oxidizable particles and the size range spread factor f(G) of the refractory particles is at least 1.

Abstract: Ceramic alloys or solid solutions are formed by dispersing a powdery metal alloy or intimate mixture of two alloying metals in a precarbonaceous polymer such as polyacrylonitrile, forming the mixture into a molded article such as fibers, and heating the molded articles at a temperature and in a pyrolyzation atmosphere sufficient to carbonize the polymer and cause reaction of the metals with carbon and/or the pyrolyzation gas.

Abstract: A sintered article of diamond is obtained by coating the surface of diamond particles with 30 to 0.1% by volume, based on the total volume of the diamond particles and aids, of at least one member selected from the group consisting of the transition metals of Groups 4a, 5a, and 6a in the Periodic Table of Elements and boron and silicon, and sintering the coated diamond particles under conditions of high pressure and high temperature, which sintered article consists of 70 to 99.8% by volume of diamond and 30 to 0.2% by volume of the carbide of the coating substance. A method for the production of the sintered article of diamond is also disclosed.

Abstract: Low density SiC ceramics having improved bending and specific strengths are prepared by (A) intimately mixing about 50-85% by weight of SiC powder with about 15-50% by weight of a preceramic polysilazane binder, (B) pulverizing the mixture to form particles having a particle size smaller than 105 micrometers, (C) separating from those particles any particles having a particle size larger than about 105 micrometers, (D) molding the resultant composition having a particle size not larger than about 105 micrometers, and (E) pyrolyzing the molded composition in an inert atmosphere to a temperature of about 1200.degree.-1450.degree. C.In a preferred embodiment of the invention, the preceramic binder is at least one polysilazane prepared by reacting an organodihalosilane with ammonia, treating the ammonolysis product with a basic catalyst which is capable of deprotonating an NH group that is adjacent to an SiH group, and quenching the resultant product with an electrophilic quenching reagent.

Abstract: The invention relates to an organopolyarylsilane which comprises aromatic ring segments having a skelton mainly comprising an aromatic condensed ring structure derived from an organic solvent soluble pitch and organosilane segments randomly bonded thereto with an Si--C linkage intervening therebetween and is soluble in an organic solvent, and further relates to an SiC--C based continuous inorganic fiber exhibiting excellent heat resistant strength, oxidation resistance and electro-conductivity, which is obtained by spinning the above organopolyarylsilane into fiber, and after infusibilizing, heat-treating said fiber under a nonreactive atmosphere at a high temperature. The above organopolyarylsilane can be efficiently obtained in extremely high yields, by a process wherein low boiling substances produced by pyrolysis of the starting material, i.e.

Abstract: A pressureless liquid phase sintering method for increasing the density of silicon carbide using a sintering composition that includes silicon carbide, calcia, and alumina.

Abstract: A wire drawing die is provided which is characterized by containing a particular thermally stable diamond compact through which a hole is formed for receiving the wire to be drawn therethrough. The thermally stable diamond compact, which preferably has a hexagonal or circular shape in plan, comprises a mass of diamond particles present in an amount of 80 to 90 percent by volume of the compact and a second phase present in an amount of 10 to 20 percent by volume of the compact, the mass of diamond particles containing substantial diamond-to-diamond bonding to form a coherent, skeletal mass and a second phase consisting essentially of silicon, the silicon being in the form of silicon and/or silicon carbide.

Abstract: A method of forming a carbothermally reduced powder of nitrides or carbides is disclosed. The product powder consists principally of unagglomerated particles and is formed by providing a collection of precursor particles in colloidal dispersion, adding to the dispersion a polymerizable monomer, polymerizing the monomer to matrix the precursor particles in discrete, well dispersed positions and carbothermally reducing the particles followed by removing excess carbon by burning. The polymer matrix acts an an agglomerate-inhibiting carbon source during carbothermal reduction.

Abstract: A sintered material for recording/reading (particularly magnetic) head slider is produced by:preparing a powdery mixture which comprises 0.5 to 6.0% by weight of at least one component selected from the component group A consisting of the following elements and compounds thereof, a garnet type compound consisting essentially of erbium oxide and aluminum oxide in amounts of 2 to 12% by weight and 0 (exclusive) to 2 (inclusive) % by weight based on the total composition, respectively, and expressed by the formula Er.sub.3 (Al,Er).sub.2 (AlO.sub.4).sub.3 through (Er,Al).sub.3 Al.sub.2 (AlO.sub.4).sub.3, and the balance being silicon carbide powder:the elements for the component group A being Ti, V, Cr, Mn, Mg, Y, Zr, Nb, Mo, Ba, La, Ce, Gd, Hf, Ta, W, Th, and Cs; andsintering the resultant mass under the application of a high pressure.Further sintering aids of Be, BeO, B and B.sub.4 C may be present. For the garnet type compound, erbium oxide may be used, preferably in combination with alumina.

Abstract: A method for making a casting nozzle, includes mixing a main casting nozzle material 70-95% by weight and electrofused aggregates 5-30% by weight, the electrofused aggregates consisting essentially of ZrO.sub.2 30-60% by weight, Al.sub.2 O.sub.3 20-50% by weight, SiO.sub.2 10-20% by weight and SiC 5-40% by weight together with a binder, thereby to make a mixture, forming the mixture in the shape of a casting nozzle thereby to make a formed body, and sintering the formed body.