Abstract: Disclosed is a method of forming an improved ceramic matrix composite wherein there is provided a slurry comprised of aluminum oxide, boron oxide and an organic binder suspended in a liquid, and combining the slurry with fibers. The aluminum oxide and boron oxide are capable of reacting to form aluminum borate. The improvement comprises providing the fibers with a coating which forms a stable interface between the fibers and the aluminum borate.

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: A ceramic-making composition comprising at least one starting powder selected from the group consisting of powders of metals, powders of metal oxides, powders of metal carbides, powders of metal nitrides and powders of metal borides, and a synthetic resin binder. To enhance plastic moldability such as injection moldability and extrusion moldability and facilitate dewaxing, a polyalkylene carbonate is used as the synthetic resin binder.

Abstract: A shaped silicon carbide-based ceramic article having an improved mechanical strength is produced at a high efficiency by a process comprising the step of: forming an organic silicone polymer, for example, polycarbosilastyrene copolymer, into a predetermined shape, for example, a filament or film; doping the shaped polymer with a doping material consisting of at least one type of halogen, for example, bromine or iodine, in an amount of 0.01% to 150% based on the weight of the shaped polymer, to render the shaped polymer infusible; and pyrolyzing the infusible shaped polymer into a shaped SiC-based ceramic article at a temperature of 800.degree. C. to 1400.degree. C. in an inert gas atmosphere, optionally the halogen-doped shaped polymer being treated with a basic material, for example, ammonia, before the pyrolyzing step, to make the filament uniformly infusible.

Abstract: A filler composition having a coefficient of thermal expansion substantially equivalent to that of SiC foam and capable of fusing and integrally bonding to SiC foam. The filler composition is useful for bonding a surface layer to a SiC foam core for optical mirrors which are used in space applications and cryogenic detectors.

Abstract: A silicon carbide sintered body for a mechanical seal which has independent pores having an average pore diameter of from 10 to 40 .mu.m and a porosity of from 4 to 13 vol %. The mechanical seal includes a stationary sliding ring and a rotary sliding ring, with at least one of the rings being the silicon carbide sintered body. The silicon carbide sintered body is preferably made of .alpha.-silicon carbide powder.

Abstract: A process for producing silicon carbide platelets and the platelets so produced. The process comprises reacting particles of a non-graphitizable form of hard carbon containing 0.5-1.5% by weight of aluminum and at least 0.2% by weight of iron (preferably anthracite coal, most preferably Pennsylvania anthracite), with silica or a silica precursor at a temperature in the range of 1900.degree.-2100.degree. C. under an inert atmosphere. If the carbon contains 0.2-1.0% by weight of iron, 0.1-10% by weight of boron, relative to the weight of SiO.sub.2, is added (if not already present). The carbon is in the form of particles of less than 50.mu. and the silica or precursor is preferably in the form of particles of less than about 1 .mu.. The weight ratio of silica to carbon is greater than 1.67:1. The resulting platelets are substantially unagglomerated and preferably of a size of less than 50.mu. with an aspect ratio greater than 5. The platelets can be used as reinforcements for ceramic and metal matrix materials.

Abstract: A carbonaceous preform is infiltrated with a silicon melt alloyed with at least one element which is substantially insoluble in silicon carbide and which forms refractory phases. The resulting silicon carbide composite has substantially no free silicon. Silicides of the alloying elements are a suitable refractory phase. Suitable alloying elements which form refractory silicides include Mo, W, Re, Hf, Zr, Cr, B, and Ti. The carbonaceous preform may include graphite particulates, carbon particulates, porous carbon skeletons, carbon-carbon composites, carbon fibers, and graphite fibers. Particulates may be incorporated into the preform for the purpose of improving mechanical properties. Suitable particulates include refractory metals, carbides, nitrides, borides, silicides, and oxides. Fiber-reinforced composites can be produced by incorporating whiskers, chopped fibers, or continuous fibers of a refractory material into the preform.

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 firing shrinkage of ceramic film casting mixtures can be increased by adding a high molecular weight mixed ester or a mixture of various high molecular weight mixed esters to them. The ceramic material of the ceramic film casting mixtures is composed preferably of lead titanate, silicon carbide, silicon nitride, beryllium oxide or aluminum oxide. Preferably, the mixed esters are derived from at least one C.sub.2 -C.sub.10 -dicarboxylic acid and at least one C.sub.8 -C.sub.24 -monocarboxylic acid. The proportion of high molecular weight mixed ester in the film casting mixture amounts to up to 5% by weight, based on the proportion of solids in the casting mixture, including sintering aids.The process makes it possible to alter the composition of a slip and still use the old tools which require an unaltered firing shrinkage.

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: There is disclosed a method for producing a self-supporting ceramic body by oxidation of a molten precursor metal with a vapor-phase oxidant to form an oxidation reaction product and inducing a molten flux comprising said molten precursor metal through said oxidation reaction product. A second metal is incorporated into said molten flux during the oxidation reaction. The resulting ceramic body includes sufficient second metal such that one or more properties of said ceramic body are at least partially affected by the presence and properties of said second metal in the metallic constituent.

Abstract: Polysilacyclobutasilazanes are reacted with chlorosilanes and/or chlorodisilanes and ammonia to provide silane-modified polysilacyclobutasilazanes having silacycles incorporated in the polymer, which silacycles are subseqentially used to cross-link the silazanes.

Abstract: A method of producing self-supporting ceramic or ceramic composite structures comprising (i) a polycrystalline oxidation reaction product formed upon oxidation of a body of molten parent metal with an oxidant, and (ii) interconnected porosity at least partially accessible from one or more surfaces of the ceramic or ceramic composite body. A second polycrystalline ceramic material is incorporated into the porosity of the ceramic or ceramic composite body to modify or contribute to its properties.

Abstract: Disclosed is a high strength aluminum borate ceramic matrix composite product and a method of making the same which comprises providing a slurry of aluminum oxide, boron oxide and organic or aqueous binder, the aluminum oxide and boron oxide capable of reacting to form aluminum borate. The slurry is introduced to a body, e.g., web of ceramic fibers, to provide an infiltrated web. After removing liquid and organic binder from the infiltrated web, it is sintered to react the aluminum oxide and boron oxide to form a ceramic matrix composite comprised of aluminum borate and said web of ceramic fibers. The reaction causes a volume expansion which aids in filling or removal of pores or voids resulting from the removal of organic binder.

Abstract: A method of producing a self-supporting ceramic composite body having therein at least one cavity which inversely replicates the geometry of a positive mold of parent metal. The method includes embedding the mold of parent metal within a conformable bed of filler to provide therein a cavity shaped and filled by the mold. The assembly is heated to melt the parent metal mold, e.g., an aluminum parent metal mold, and contacted with an oxidant to oxidize the molten parent metal to form a polycrystalline material which grows through the surrounding bed of filler, the molten metal being drawn through the growing polycrystalline material to be oxidized at the interface between the oxidant and previously formed oxidation reaction product whereby the cavity formerly filled by the mold of parent metal is eventually evacuated of the metal. There remains behind a cavity whose shape inversely replicates the original shape of the mold.

Abstract: A method for forming extremely homogeneous metal and ceramic composites wherein a dispersion of metal and/or ceramic powders in a polymer solution, such as a solution of an organic binder, is precipitated by the addition of a second, miscible solvent in which the polymer is insoluble. The resulting precipitated second phase is compacted, dried and processed to form an extremely uniform composite with excellent physical properties. The method has advantages over other processes since it is relatively flexible and inexpensive yet yields a high quality product.

Abstract: A powder comprising an alloy of a refractory material and carbothermic reaction product produced by carbothermically reacting a blend of at least two metal oxides.

Abstract: The present invention relates to a ceramic foam material, preferably a ceramic foam filter, prepared by providing an open cell flexible foam having a plurality of interconnected voids surrounded by a web of the flexible foam, applying an adhesion promoting material to at least one surface of the flexible foam, impregnating the flexible foam after applying the adhesion promoting material with a ceramic slurry, drying and heating the impregnated material to remove the organic component therefrom, and firing at an elevated temperature to form the filter. In a preferred embodiment, a flocked coating is formed on at least on surface of the flexible foam prior to impregnation. The flocked coating may be formed either by first applying a solution containing an adhesive to the surface(s) and thereafter applying fibers to the surface or by applying a solution containing the adhesive and the fibers.

Abstract: Method for rapidly growing silicon carbide whiskers having high aspect ratios comprising heating a carbon substrate to between about 1600.degree. C. and 1800.degree. C. and thereat contacting the substrate with a reactive atmosphere consisting essentially of gaseous species of silicon, carbon, nitrogen, sulfur and a group II metal selected from the group consisting of calcium, magnesium and barium.

Abstract: A processing for producing silicon carbide whiskers in which a source of silica is mixed with a residual oil or crude petroleum and the resultant mixture is heated in a substantially nonoxidizing atmosphere at temperature sufficiently high to carbonize the residual oil or crude petroleum, thereby forming an intimate mixture of carbon and silica. The intimate mixture is then heated in a nonoxidizing atmosphere in the presence of a seeding component comprising an element selected from the group consisting of boron, the rare earths, Group IA, Group IB, Group VB, Group VIB, Group VIIB and Group VIII of the Periodic Table of Elements at temperatures sufficiently high to induce the reaction between carbon and silica to form silicon carbide. The resultant silicon carbide product will contain a relatively high concentration of silicon carbide whiskers.

Abstract: A surface of an optical fiber is coated by a method for coating a surface of an optical fiber with carbon comprising steps of introducing an optical fiber in a reaction chamber containing a coating raw material comprising carbon, hydrogen and halogen atoms and depositing on the surface of the optical fiber a carbon layer formed from the raw material by chemical vapor deposition, whereby the coated optical fiber has improved initial tensile strength and absorbs less hydrogen.

Abstract: A ceramic material and a method of forming a ceramic material which possesses a high impact resistance. The material comprises: (a) a first continuous phase of .beta.-SiC; and (b) a second phase of about 25-40 vol % TiB.sub.2. Al.sub.2 O.sub.3 is preferably used as a densification aid. The material is formed by hot-pressing the mixture at a temperature from greater than about 1800.degree. C. to less than the transition temperature of .beta.-SiC to .alpha.-SiC. The hot-pressing is performed at a pressure of about 2000 psi to about 4000 psi in an inert atmosphere for several hours and results in the formation of a two phase sintered ceramic composite material.

Abstract: The present invention relates to an unfired refractory brick for use in reducing conditions at temperatures above 1800.degree. F. The brick comprises a matrix of alumino-silicate clays, alumino-silicate-aggregates and high alumina aggregates. It also has 2 to 20% by weight of finally ground silicon carbide and 2 to 20% by weight of fine carbon particles distributed throughout the matrix. The matrix also includes a water soluble ammonium lignin sulphonate as a chemical binding agent. The brick of the present invention finds particular use in a furnace for kiln baking anodes used in the electrolytic production of aluminum metal.

Abstract: A powder-containing composition, such as a boron nitride-containing composition for use as a film-forming coating on substrates, comprising particulate powders and particulate clay dispersed in water. The composition is also suitable for use in aerosol cans.

Abstract: A sintered silicon nitride contains at least 90% of .beta.-type silicon nitride, wherein said .beta.-type silicon nitride consists essentially of 35 to 80% of large crystal particles with the remainder of small crystal particles, said large crystal particles having a mean particle length being at least two times as long as that of said small crystal particles. This sintered silicon nitride is obtained by a method wherein one batch of starting silicon nitride powders, whose primary particles have a mean particle size of 0.1 to 0.5 .mu.m, and another batch of starting silicon nitride powders, whose primary particles have a mean particle size of 0.5 to 0.7 .mu.m, are blended with a sintering aid or aids at a given weight ratio, and the thus obtained blend is formed or compacted and sintered.

Abstract: A process for the preparation of a methylpolysilane having a controlled carbon content is provided which includes the steps of heating together to form a reaction mixture at least one alkoxy-functional disilane selected from the group consisting of disilanes having two, three, and four alkoxy groups bonded to the silicon atoms, and mixtures thereof, with either an alkoxy-functional silane having at least one unsaturated substituent or an unsaturated hydrocarbon compound in an amount effective to increase the carbon content of the resulting polymer. The reaction is carried out in the presence of a catalyst which is a source of alkoxide ions. The methylpolysilane polymers produced may be pyrolyzed to form ceramic compositions having increased carbon contents. The ceramics may find use as films, fibers, and coatings, as well as the many other uses to which silicon carbide ceramics have heretofore been put.

Abstract: A process for the preparation of a methylpolysilane having a controllable rheology, including a controllable glass transition temperature is provided which includes the steps of heating together at least one alkoxy-functional disilane selected from the group consisting of disilane having three and four alkoxy groups bonded to the silicon atoms, and mixtures thereof, with an amount of a dialkoxy disilane effective to control the glass transition temperature of the resulting polymer within the range of from about 0.degree. to about 200.degree. C. The reaction is carried out in the presence of a catalyst which is a source of alkoxide ions to catalyze the redistribution reaction. The redistribution reaction produces oligomer and longer chain polymeric silanes having greater than seven silicon atoms in the polymer chain. Methylpolysilanes formed in accordance with the practice of the present invention may then be readily formed into fibers by a conventional spinning process.

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 method of producing a silicon carbide-based body by infiltrating with molten silicon a porous compact comprising silicon carbide, carbon, and a secondary phase dispersed within the compact. The secondary phase might comprise a titanium compound, or a metal carbide.

Abstract: Silicon carbide whisker-reinforced ceramic composites are fabricated in a highly reproducible manner by beneficating the surfaces of the silicon carbide whiskers prior to their usage in the ceramic composites. The silicon carbide whiskers which contain considerable concentrations of surface oxides and other impurities which interact with the ceramic composite material to form a chemical bond are significantly reduced so that only a relatively weak chemical bond is formed between the whisker and the ceramic material. Thus, when the whiskers interact with a crack propagating into the composite the crack is diverted or deflected along the whisker-matrix interface due to the weak chemical bonding so as to deter the crack propagation through the composite. The depletion of the oxygen-containing compounds and other impurities on the whisker surfaces and near surface region is effected by heat treating the whiskers in a suitable oxygen sparaging atmosphere at elevated temperatures.

Abstract: A method of flame spraying refractory material for in situ repair of, e.g., furnace linings wherein an inert carrier gas incapable of supporting combustion and particles of refractory oxide and combustible metal or other oxidizable material are delivered to a flame spraying apparatus wherein high pressure oxygen aspirates and accelerates the carrier gas-particle mixture; a controlled ratio of 5 to 1 to about 30 to 1 oxygen gas to carrier gas; allows for the use of highly combustible metals and materials such as chromium, aluminum, zirconium, and/or magnesium as heat sources without back-flash and at a deposition rate in excess of 2000 pounds per hour of refractory oxide to yield a deposited refractory mass exhibiting enhanced wear and erosion resistance.

Abstract: A powdery mixture of a fine silicon carbide powder admixed with boron or a boron compound, e.g. boron carbide, titanium boride and boron oxide, as a sintering aid is compression-molded into a green body which is subjected to a sintering treatment into a sintered body. Different from conventional methods in which the sintering treatment is performed always in an atmosphere of an inert gas, e.g. argon, the sintering treatment in the inventive method is performed in an atmosphere of a rare gas containing 0.005-5% by volume of nitrogen. The sintered body of silicon carbide obtained by this method has an outstandingly high electric volume resistivity of 10.sup.10 to 10.sup.13 ohm.cm and a coefficient of thermal conductivity of 100-220 W/m.K.

Abstract: A SiC whisker-reinforced ceramic article produced by subjecting the SiC whiskers to acid- and/or base-washing; subjecting ceramic particles and SiC whiskers to fluid classification; forming a suspension of the powdered ceramic and SiC whiskers; consolidating the suspension to form a green compact; optionally infiltrating the green compact with an aluminum compound which is a precursor to Al.sub.2 O.sub.3, and pressureless sintering the green compact to produce an SiC whisker-reinforced composite having high relative density at high SiC whisker loading.

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 ceramic injection molded body which is heated to remove organic binder and then hydrostatically pressed after injection molding. The molded body has a volume of fine pores having a diameter of at least 0.1 .mu.m being at least 30% of the total volume of fine pores in the molded body after removed of organic binders, and the volume of fine pores having a diameter of at most 0.1 .mu.m being at least 50% of the total volume of fine pores in the molded body after hydrostatic pressing.

Abstract: A method of physically and chemically altering asbestos which comprises mixing the asbestos with a selected metal and reacting the mixture to form an end product including slag, in which the asbestos has been altered allowing its safe disposal or its formation into useful products.

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: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.

Abstract: Ceramic molding or casting powders, particularly nitride, oxide and carbide powders, that have substantial internal surface and volume produce improved dispersions after being coated with a cover material, such as polyethylene glycol, that reduces the specific surface area of the powder by at least about 10% and reduces the amount of penentration of the binder used for dispersion into the internal volume of the powder. The viscosity of dispersions of such coated powders, or of conventional uncoated ceramic powders, can be further reduced by treatment of the powders with organotitanate, organozirconate, or organosilane coupling agents that are chosen to interact favorably with the specific powders and binders used.

Abstract: Process for production of a ceramic material, e.g. a carbide, nitride, boride or silicide, by reacting at least one compound of a metallic or non-metallic element having two or more goups reactive with hydroxyl groups with at least one organic compound having two or more hydroxyl groups to form an oxygen-containing polymeric product, heating the polymeric product to produce a coked product containing carbon and an oxide of the metallic or non-metallic element, and heating the coked product to produce a ceramic maerial, in which the proportion by weight of carbon to the oxide of the metallic or non-metallic element in the coked product is in the range from 50% to 150% of the proportion which is theoretically required to produce the ceramic material.

Abstract: Silicon carbide whisker-reinforced ceramic composites are fabricated in a highly reproducible manner by beneficating the surfaces of the silicon carbide whiskers prior to their usage in the ceramic composites. The silicon carbide whiskers which contain considerable concentrations of surface oxides and other impurities which interact with the ceramic composite material to form a chemical bond are significantly reduced so that only a relatively weak chemical bond is formed between the whisker and the ceramic material. Thus, when the whiskers interact with a crack propagating into the composite the crack is diverted or deflected along the whisker-matrix interface due to the weak chemical bonding so as to deter the crack propagation through the composite. The depletion of the oxygen-containing compounds and other impurities on the whisker surfaces and near surface region is effected by heat treating the whiskers in a suitable oxygen sparaging atmosphere at elevated temperatures.

Abstract: Novel ceramic matrix composition comprising toughened ceramic layers interlaminated with fiber-reinforced ceramic layers and offering improved off-axis and axial properties, are described. The fiber-reinforced layers comprise inorganic reinforcing fibers disposed in a ceramic matrix material, with the reinforcing fibers being oriented along axes parallel with the planes of the layers, while the toughened ceramic layers comprise inorganic whiskers or chopped fibers randomly oriented in the layers.

Abstract: The present invention relates to copolymers containing --Si--N-- and --Si--Si-- bonds, which are obtained by the polycondensation ofat least one silane of the formula RR.sub.1 SiCl.sub.2and at least one disilazane of the formula ##STR1## in which formulae: R.sub.2 is a halogen atom, preferably Br and Cl, andR, R.sub.1 and R.sub.3, which are identical or different, represent a hydrogen atom or an alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, alkylaryl or alkenylaryl hydrocarbon radical which may be functional,to a process for the preparation of the said copolymers,to the polycarbosilazanes obtained by thermolysis of the said copolymers and to the silicon carbonitrides obtained by heating the said polycarbosilazanes.

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: Ceramic-metal composites (cermets) are made by a combination of self-propagating high temperature combustion synthesis and molten metal infiltration. Solid-gas, solid-solid and solid-liquid reactions of a powder compact produce a porous ceramic body which is infiltrated by molten metal to produce a composite body of higher density. AlN-Al and many other materials can be produced.

Abstract: A method of preparing an organosilazane including reacting a first halosilane having the formula RR.sup.1 SiX.sub.2, wherein X is F, Cl, Br, or I, and each R and R.sup.1, independently, is X, H, or a lower alkyl group; a first primary amine compound having the formula R.sup.2 NH.sub.2, wherein R.sup.2 is H or a lower alkyl group; and a second primary amine compound having the formula R.sup.3 NH.sub.2, wherein R.sup.3 is H or a lower alkyl group, R.sup.3 being different from R.sup.2, to form the organosilazane.

Abstract: A compound or composite powder which includes metallic or ceramic whiskers embedded in a metallic or ceramic matrix as host material, the whiskers have a length between 5.times.10.sup.-6 m and 2.times.10.sup.-4 m and diameters between 2.times.10.sup.-7 m and 1.times.10.sup.-5 m, and are embedded in the matrix with a volume proportion of whisker content between 1 to 50% (by volume), the reference being to a pore-free compacted compound/composite material; the whiskers being made of SiC, Si.sub.-3 N.sub.-4, Al.sub.-2 O.sub.-3 or ZrO.sub.-2 and are embedded in a ceramic matrix being Al.sub.-2 O.sub.-3, Al.sub.-2 O.sub.-3 +from 5 to 40% ZrO.sub.-2 +from 0 to 5% Y.sub.-2 O.sub.-3 or ZrO.sub.-2 with 3 to 15% Y.sub.-2 O.sub.-3 or Si-nitride or Si-carbide. Alternatively the whiskers are made of Si.sub.-3 N.sub.-4, Al.sub.-2 O.sub.-3, ZrO.sub.-2 or W and the matrix is made of W, Mo, Fe, Ni, Co, Cu or an alloy thereof.

Abstract: A method of increasing the life of tuyere area refractories through repeated application of coherent refractory mass formed by ceramic welding process onto worn area after installing protective removable, expendable or reuseable pipes/rods. Consecutive use of this process can effectively suspend or reduce or control the wear of the original refractories.