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5545435 Method of making a toughened ceramic composite comprising chemical vapor deposited carbon and ceramic layers on a fibrous preform
PatentsAlert metal silicide, metal nitride, and metal diboride, on the metal oxide coating. The reinforcement fibers being fibers from the group consisting of elemental carbon, silicon carbide, and mixtures thereof. A process for producing the fiber reinforced composite comprises depositing on the fibers a continuous coating comprised of the first layer of the metal oxide, and the second layer. A carbonaceous material is admixed with the coated fibers so that at least 5 volume percent of the mixture is the fibers. The mixture is formed into a preform having an open porosity ranging from about 25 volume percent to about 90 volume percent of the preform. The preform is heated in an inert atmosphere or partial vacuum, and infiltrated with molten silicon to produce an infiltrated product having the composition of the composite.
The invention relates to a sintered composite of silicon carbide and silicon nitride. The sintered composite includes a polycrystalline matrix and polycrystalline aggregates dispersed in the matrix. The matrix includes silicon carbide grains, first silicon-nitride grains and a first sintering aid thereof. Each of the aggregates includes second silicon-nitride grains and a second sintering aid thereof. The aggregates have an average diameter within a range from 10 mum to 50 mum. This average diameter is defined as a diameter of a circle having an area which is the same as the average area of the aggregates on a two-dimensional section of the sintered composite. The sintered composite is light in weight and superior in strength and fracture toughness at high temperature as well as at room temperature.
MANUFACTURE
5540950 COMPOSITE OF SILICON CARBIDE AND CARBON AND METHOD OF MAKING THE SAME Izawa Hajim; Arai Takehito; Yamamoto Taij; Toyonaka, JAPAN assigned to Sumitomo Osaka Cement Co Ltd This invention relates to a composite of silicon carbide and carbon. This invention also relates to its manufacturing method. An obtained composite is used as heat resistant, wear resistant or chemical resistant materials. The object of this manufacturing method is to form a deep layer of silicon carbide and carbon in the surface of a carbon base by a simple process of causing a silicon containing material to penetrate into and react with the carbon block. Further object of this invention is to produce a compound in whole comprised of silicon carbide and carbon if the carbon block is 20 mm or below in thickness. To this end, according to this forming method a carbon block having a lattice constant c of 6.708 #521 +0 to 6.900 +521+0 or below and a density of 1.3 g/cm+HU 3 +L to 1.7 g/cm+HU 3 +L or below is formed into a desired shape, and molten silicon containing material is caused to penetrate into and react with the carbon block thereby to obtain a surface layer composed to silicon carbide and carbon to a surface depth of 20 mm or below and having substantially the same shape as the carbon block.+RE
5541143 SINTERED COMPOSITE OF SILICON CARBIDE AND SILICON NITRIDE Hirosaki Naoto; Akimune Yoshio; Okamoto Yusuke; Yokohama, JAPAN assigned to Nissan Motor Co Ltd
5545435 METHOD OF MAKING A TOUGHENED CERAMIC COMPOSITE COMPRISING CHEMICAL VAPOR DEPOSITED CARBON AND CERAMIC LAYERS ON A FIBROUS PREFORM Steffier Wayne; Huntington Beach, CA, UNITED STATES assigned to Hyper-Therm High Temperature Composites Inc A fiber-reinforced ceramic-matrix composite material exhibiting high tensile strength, high fracture toughness and high-temperature oxidation resistance is produced by alternatively depositing multiple thin layers of ceramic material separated by very thin intermediate layers of fugitive carbon onto the fiber reinforcement prior to the subsequent densification with the ceramic matrix. The energy behind propagating matrix cracks in the resulting composite material are effectively dissipated by the progressive increase in crack deflection/branching and frictional slip through the successive ceramic layers of the multilayer fiber coating system. These energy release and arrest mechanisms sufficiently impede the driving force behind unstable crack propagation and render the cracks non-critical, thereby serving to blunt and/or divert propagating matrix cracks at or around the reinforcing fiber. While significantly increasing the strength and fracture toughness of the composite, the multilayer refractory fiber coating system enables the composite to remain oxidatively stable when stressed at or beyond the matrix cracking stress point and subsequently exposed to temperatures above 800°C in air.
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The invention relates to a sintered composite of silicon carbide and silicon nitride. The sintered composite includes a polycrystalline matrix and polycrystalline aggregates dispersed in the matrix. The matrix includes silicon carbide grains, first silicon-nitride grains and a first sintering aid thereof. Each of the aggregates includes second silicon-nitride grains and a second sintering aid thereof. The aggregates have an average diameter within a range from 10 mum to 50 mum. This average diameter is defined as a diameter of a circle having an area which is the same as the average area of the aggregates on a two-dimensional section of the sintered composite. The sintered composite is light in weight and superior in strength and fracture toughness at high temperature as well as at room temperature.
MANUFACTURE
5540950 COMPOSITE OF SILICON CARBIDE AND CARBON AND METHOD OF MAKING THE SAME Izawa Hajim; Arai Takehito; Yamamoto Taij; Toyonaka, JAPAN assigned to Sumitomo Osaka Cement Co Ltd This invention relates to a composite of silicon carbide and carbon. This invention also relates to its manufacturing method. An obtained composite is used as heat resistant, wear resistant or chemical resistant materials. The object of this manufacturing method is to form a deep layer of silicon carbide and carbon in the surface of a carbon base by a simple process of causing a silicon containing material to penetrate into and react with the carbon block. Further object of this invention is to produce a compound in whole comprised of silicon carbide and carbon if the carbon block is 20 mm or below in thickness. To this end, according to this forming method a carbon block having a lattice constant c of 6.708 #521 +0 to 6.900 +521+0 or below and a density of 1.3 g/cm+HU 3 +L to 1.7 g/cm+HU 3 +L or below is formed into a desired shape, and molten silicon containing material is caused to penetrate into and react with the carbon block thereby to obtain a surface layer composed to silicon carbide and carbon to a surface depth of 20 mm or below and having substantially the same shape as the carbon block.+RE
5541143 SINTERED COMPOSITE OF SILICON CARBIDE AND SILICON NITRIDE Hirosaki Naoto; Akimune Yoshio; Okamoto Yusuke; Yokohama, JAPAN assigned to Nissan Motor Co Ltd
5545435 METHOD OF MAKING A TOUGHENED CERAMIC COMPOSITE COMPRISING CHEMICAL VAPOR DEPOSITED CARBON AND CERAMIC LAYERS ON A FIBROUS PREFORM Steffier Wayne; Huntington Beach, CA, UNITED STATES assigned to Hyper-Therm High Temperature Composites Inc A fiber-reinforced ceramic-matrix composite material exhibiting high tensile strength, high fracture toughness and high-temperature oxidation resistance is produced by alternatively depositing multiple thin layers of ceramic material separated by very thin intermediate layers of fugitive carbon onto the fiber reinforcement prior to the subsequent densification with the ceramic matrix. The energy behind propagating matrix cracks in the resulting composite material are effectively dissipated by the progressive increase in crack deflection/branching and frictional slip through the successive ceramic layers of the multilayer fiber coating system. These energy release and arrest mechanisms sufficiently impede the driving force behind unstable crack propagation and render the cracks non-critical, thereby serving to blunt and/or divert propagating matrix cracks at or around the reinforcing fiber. While significantly increasing the strength and fracture toughness of the composite, the multilayer refractory fiber coating system enables the composite to remain oxidatively stable when stressed at or beyond the matrix cracking stress point and subsequently exposed to temperatures above 800°C in air.
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