Abstract:
A silicon carbide powder which can increase the densities of a green body and a sintered silicon carbide, a method of producing a green body having a high density and excellent handling properties, and a method of producing a sintered silicon carbide having a high density, in which methods the silicon carbide powder is used. The silicon carbide powder includes at a particulate volume ratio of 20% to 80% a silicon carbide powder whose model ratio is 1.7 &mgr;m to 2.7 &mgr;m and a silicon carbide powder whose model ratio is 10.5 &mgr;m to 21.5 &mgr;m. The silicon carbide powder is used in the method of producing a green body and in the method of producing a sintered silicon carbide powder.
Abstract:
A method comprising incorporation of an inorganic polymer precursor of a grain growth inhibitor into nanostructured materials or intermediates useful for the production of nanostructured materials. The precursor/nanostructured material composite is optionally heat treated at a temperature below the grain growth temperature of the nanostructured material in order to more effectively disperse the precursor. The composites are then heat treated at a temperature effective to decompose the precursor and to form nanostructured materials having grain growth inhibitors uniformly distributed at the grain boundaries. Synthesis of the inorganic polymer solution comprises forming an inorganic polymer from a solution of metal salts, filtering the polymer, and drying. Alloying additives as well as grain growth inhibitors may be incorporated into the nanostructured materials.
Abstract:
An improved submerged entry nozzle is provided which is useful in the casting of aluminum killed molten steel. The nozzle has an improved slagline sleeve or collar which surrounds the outer portion of the nozzle to protect it from corrosion during the casting process. The slagline sleeve is made from resin bonded zirconia/graphite which has been formulated so that upon curing of the resin to form resite, there is a reduction in the contractile tendency which results in a reduction in stress fracturing. The reduction of the contractile tendency and the resulting resistance to stress fracturing is achieved by adding an effective amount of calcium oxide to the resin-zirconia-graphite mixture which is used to form the sleeve.
Abstract:
An improved submerged entry nozzle is provided which is useful in the casting of aluminum killed molten steel. The nozzle has an improved slagline sleeve or collar which surrounds the outer portion of the nozzle to protect it from corrosion during the casting process. The slagline sleeve is made from resin bonded zirconia/graphite which has been formulated so that upon curing of the resin to form resite, there is a reduction in the contractile tendency which results in a reduction in stress fracturing. The reduction of the contractile tendency and the resulting resistance to stress fracturing is achieved by adding an effective amount of calcium oxide to the resin-zirconia-graphite mixture which is used to form the sleeve.
Abstract:
An molded product of activated carbon produced by molding a kneaded mixture containing an activated carbon, a solvent, and a phenol-aldehyde type resin being solid in a normal temperature and containing 50 to 95% by weight of components soluble in the solvent used, drying and curing the molding, and then carbonizing the molding in an inert gas has a high adsorption capability and a high mechanical strength, e.g., a compressive strength, especially the strength after being contacted with an acid or water.
Abstract:
A fullerene-dispersed ceramic is produced by an improved method in which C60 or like fullerene, and C16TMA or like surfactant, are dissolved in a solution of metallic compound, such as zirconyl nitrate, to form a colloidal solution. A gel is formed from the colloidal solution by changing its hydrogen ion concentration. The gel is dried and subjected to heat treatment, to eliminate remaining solvent and surfactant, and thereby stably obtain the desired fullerene-dispersed ceramic powder in which the fullerene is uniformly dispersed and which is essentially free from carbon other than fullerene.
Abstract:
A ceramic material suitable for use in production of paving tiles, construction tiles, flooring in offices, flooring in machinery plants and so forth is obtained by a method comprising steps of mixing defatted bran derived from rice bran with a thermosetting resin before kneading, subjecting a kneaded mixture thus obtained to a primary firing in an inert gas at a temperature in a range of 700 to 1000° C., pulverizing the kneaded mixture after the primary firing into carbonized powders, kneading the carbonized powders with which ceramic powders, a solvent, and a binder as desired are mixed into a plastic workpiece (kneaded mass), pressure-forming the plastic workpiece at pressure in a range of 10 to 100 MPa, and subjecting a formed plastic workpiece thus obtained again to firing in an inert gas atmosphere at a temperature in a range of 100 to 1400° C.
Abstract:
A molded part of a ceramic material derived from polymers includes a composite body of a single-phase or multi-phase, amorphous, partially crystalline or crystalline matrix of silicon carbide (SiC), silicon nitride (Si3N4), silicon dioxide (SiO2) or mixtures thereof. The matrix contains graphite inclusions and the density of the ceramic material is at least 85% of the theoretical value. The molded part is produced by subjecting a mixture formed of a polymer component in an amount of 30 to 80 wt. % referred to the total weight of the mixture, fillers in an amount of 0 to 30 wt. % and graphite in an amount of 10 to 70 wt. %, to a forming process with heating to effect crosslinking of the polymer components, followed by a pyrolysis process. In particular, the molded parts are produced from polymers of the group including polysilanes, polysiloxanes, polysilazanes or polycarbosilanes. A process for producing ceramic molded parts and a sliding element having a molded part are also provided.
Abstract:
A refractory castable composition is disclosed comprising one hundred weight percent of a refractory composition comprising from about 60 to 90 weight percent of a refractory aggregate, from about 2 to 25 weight percent of an ultrafine refractory material having an average particle diameter size less than or equal to about 3 microns, from about 0.5 to 15 weight percent of a binder, and from about 0.05 to 2.0 weight percent of a dispersant, wherein all or a portion of the ultrafine refractory material comprises a thermal black such that the refractory composition comprises from about 2 to 15 weight percent of the thermal black, and from about 3 to 10 weight percent water based upon 100 weight percent of the refractory composition, and wherein the water is present in an amount sufficient to achieve a castable consistency. A method of installing the refractory castable composition is also disclosed.