Abstract: The present invention relates to an unsintered composite powder composition comprising silicon carbide and aluminium nitride, a sintering process and a sintered silicon carbide material obtained or obtainable therefrom, as well as a SiC—AlN composite ceramic, uses thereof and articles comprising the same. In one aspect, the present invention provides an unsintered composite powder composition comprising from 90.0% to 99.9% by weight silicon carbide and from 0.1% to 10% by weight of aluminium nitride. In another aspect, the present invention provides a SiC—AlN composite ceramic material having the formula x(SiC)—1-x (AlN), wherein 0.999?x?0.900; and wherein the composite ceramic material has a fracture toughness of greater than 4.5 MPa·m1/2; and a thermal conductivity of greater than 120 W/m K.

Abstract: A lining for a metallurgical vessel is configured to have an engineered porosity. The lining contains a plurality of regions, each extending in a primary plane of the lining, each region having a differing value of total pore or perforation area as measured in a primary plane of the lining. The lining may be used to form part or all of the working surface of the floors or walls of the vessel. In casting use the lining produces an oxidation buffering layer at an interphase of metal melt extending from the interface between metal melt and the walls and floor of the metallurgical vessel, such that when in casting use, the metal flow rate in said oxidation buffering layer is substantially nil, and the concentration of endogenous inclusions, in particular oxides, in said oxidation buffering layer is substantially higher than in the bulk of the metal melt.

Abstract: A lining for a metallurgical vessel is configured to have an engineered porosity. The lining contains a plurality of regions, each extending in a primary plane of the lining, each region having a differing value of total pore or perforation area as measured in a primary plane of the lining. The lining may be used to form part or all of the working surface of the floors or walls of the vessel. In casting use the lining produces an oxidation buffering layer at an interphase of metal melt extending from the interface between metal melt and the walls and floor of the metallurgical vessel, such that when in casting use, the metal flow rate in said oxidation buffering layer is substantially nil, and the concentration of endogenous inclusions, in particular oxides, in said oxidation buffering layer is substantially higher than in the bulk of the metal melt.

Abstract: A highly porous substrate is provided using an extrusion system. More particularly, the present invention enables the production of a highly porous substrate. Depending on the particular mixture, the present invention enables substrate porosities of about 60% to about 90%, and enables advantages at other porosities, as well. The extrusion system enables the use of a wide variety of fibers and additives, and is adaptable to a wide variety of operating environments and applications. Fibers, which have an aspect ratio greater than 1, are selected according to substrate requirements, and are typically mixed with binders, pore-formers, extrusion aids, and fluid to form a homogeneous extrudable mass. The homogeneous mass is extruded into a green substrate. The more volatile material is preferentially removed from the green substrate, which allows the fibers to form interconnected networks.

Abstract: A fibrous ceramic material comprises a plurality of fibers having a RxMg2Al4+xSi5?xO18 or RxMg2?xAl4Si5O18 compositional structure. The fibrous ceramic material is form by combining two or more RxMg2Al4+xSi5?xO18 or RxMg2?xAl4Si5O18 precursors in which at least one of the two or more RxMg2Al4+xSi5?xO18 or RxMg2?xAl4Si5O18 precursors is in fiber form. The fibrous ceramic material is shaped to form a fibrous body in which at least about 20% of all fibers therein are aligned in a substantially common direction.

Abstract: A fibrous ceramic material comprises a plurality of fibers having a modified aluminosilicate compositional structure (i.e., x(RO).y(Al2O3).z(SiO2) or w(MO).x(RO).y(Al2O3).z(SiO2)). The fibrous ceramic material is form by combining two or more x(RO).y(Al2O3).z(SiO2) or w(MO).x(RO).y(Al2O3).z(SiO2) precursors in which at least one of the two or more precursors is in fiber form. The resulting fibrous ceramic material has a low coefficient of thermal expansion (i.e., ?4.7×10-6/° C.).

Abstract: A method is provided for producing a highly porous substrate. More particularly, the present invention enables fibers, such as organic, inorganic, glass, ceramic, polymer, or metal fibers, to be combined with binders and additives, and extruded, to form a porous substrate. Depending on the selection of the constituents used to form an extrudable mixture, the present invention enables substrate porosities of about 60% to about 90%, and enables process advantages at other porosities, as well. The extrudable mixture may use a wide variety of fibers and additives, and is adaptable to a wide variety of operating environments and applications. Additives can be selected that form inorganic bonds between overlapping fibers in the extruded substrate that provide enhanced strength and performance of the porous substrate in a variety of applications, such as, for example, filtration and as a host for catalytic processes, such as catalytic converters.

Abstract: A highly porous substrate is provided using an extrusion system. More particularly, the present invention enables the production of a highly porous substrate. Depending on the particular mixture, the present invention enables substrate porosities of about 60% to about 90%, and enables advantages at other porosities, as well. The extrusion system enables the use of a wide variety of fibers and additives, and is adaptable to a wide variety of operating environments and applications. Fibers, which have an aspect ratio greater than 1, are selected according to substrate requirements, and are typically mixed with binders, pore-formers, extrusion aids, and fluid to form a homogeneous extrudable mass. The homogeneous mass is extruded into a green substrate. The more volatile material is preferentially removed from the green substrate, which allows the fibers to form interconnected networks.

Abstract: This invention provides a system and method for establishing proper quantities of components in the initial mixture to be used in the fabrication of a porous ceramic substrate. The components typically consist of a solvent, a bulk fiber such as mullite, an organic binder for use in extrusion of the green substrate, a glass/clay bonding phase that bonds the fibers upon high-temperature curing and a pore former that defines gaps between the particles and is vaporized out of the substrate during curing. By identifying the controllable factors related to each of the components, and adjusting the factors to vary the resulting strength and porosity of the cured substrate, an optimized strength and porosity performance can be achieved. The controlling factors for each component include its relative weight percent in the mixture. The fiber component is also controlled via fiber diameter, diameter uniformity, and fiber length-to-diameter aspect ratio.

Abstract: A method is provided for producing a highly porous substrate. More particularly, the present invention enables fibers, such as organic, inorganic, glass, ceramic, polymer, or metal fibers, to be combined with binders and additives, and extruded, to form a porous substrate. Depending on the selection of the constituents used to form an extrudable mixture, the present invention enables substrate porosities of about 60% to about 90%, and enables process advantages at other porosities, as well. The extrudable mixture may use a wide variety of fibers and additives, and is adaptable to a wide variety of operating environments and applications. Additives can be selected that form inorganic bonds between overlapping fibers in the extruded substrate that provide enhanced strength and performance of the porous substrate in a variety of applications, such as, for example, filtration and as a host for catalytic processes, such as catalytic converters.

Abstract: A highly porous substrate is provided using an extrusion system. More particularly, the present invention enables the production of a highly porous substrate. Depending on the particular mixture, the present invention enables substrate porosities of about 60% to about 90%, and enables advantages at other porosities, as well. The extrusion system enables the use of a wide variety of fibers and additives, and is adaptable to a wide variety of operating environments and applications. Fibers, which have an aspect ratio greater than 1, are selected according to substrate requirements, and are typically mixed with binders, pore-formers, extrusion aids, and fluid to form a homogeneous extrudable mass. The homogeneous mass is extruded into a green substrate. The more volatile material is preferentially removed from the green substrate, which allows the fibers to form interconnected networks.

Abstract: A method is provided for producing a highly porous substrate. More particularly, the present invention enables fibers, such as organic, inorganic, glass, ceramic, polymer, or metal fibers, to be combined with binders and additives, and extruded, to form a porous substrate. Depending on the selection of the constituents used to form an extrudable mixture, the present invention enables substrate porosities of about 60% to about 90%, and enables process advantages at other porosities, as well. The extrudable mixture may use a wide variety of fibers and additives, and is adaptable to a wide variety of operating environments and applications. Additives can be selected that form inorganic bonds between overlapping fibers in the extruded substrate that provide enhanced strength and performance of the porous substrate in a variety of applications, such as, for example, filtration and as a host for catalytic processes, such as catalytic converters.

Abstract: A method is provided for producing a highly porous substrate. More particularly, the present invention enables fibers, such as organic, inorganic, glass, ceramic, polymer, or metal fibers, to be combined with binders and additives, and extruded, to form a porous substrate. Depending on the selection of the constituents used to form an extrudable mixture, the present invention enables substrate porosities of about 60% to about 90%, and enables process advantages at other porosities, as well. The extrudable mixture may use a wide variety of fibers and additives, and is adaptable to a wide variety of operating environments and applications. Additives can be selected that form inorganic bonds between overlapping fibers in the extruded substrate that provide enhanced strength and performance of the porous substrate in a variety of applications, such as, for example, filtration and as a host for catalytic processes, such as catalytic converters.

Abstract: A fibrous ceramic material comprises a plurality of fibers having a RxMg2Al4+xSi5?xO18 or RxMg2?xAl4Si5O18 compositional structure. The fibrous ceramic material is form by combining two or more RxMg2Al4+xSi5?xO18 or RxMg2?xAl4Si5O18 precursors in which at least one of the two or more RxMg2Al4+xSi5?xO18 or RxMg2?xAl4Si5O18 precursors is in fiber form. The fibrous ceramic material is shaped to form a fibrous body in which at least about 20% of all fibers therein are aligned in a substantially common direction.

Abstract: A fibrous ceramic material comprises a plurality of fibers having a modified aluminosilicate compositional structure (i.e., x(RO).y(Al2O3).z(SiO2) or w(MO).x(RO).y(Al2O3).z(SiO2)). The fibrous ceramic material is form by combining two or more x(RO).y(Al2O3).z(SiO2) or w(MO).x(RO).y(Al2O3).z(SiO2) precursors in which at least one of the two or more precursors is in fiber form. The resulting fibrous ceramic material has a low coefficient of thermal expansion (i.e., ?4.7×10?6/° C.).

Abstract: A highly porous substrate is provided using an extrusion system. More particularly, the present invention enables the production of a highly porous substrate. Depending on the particular mixture, the present invention enables substrate porosities of about 60% to about 90%, and enables advantages at other porosities, as well. The extrusion system enables the use of a wide variety of fibers and additives, and is adaptable to a wide variety of operating environments and applications. Fibers, which have an aspect ratio greater than 1, are selected according to substrate requirements, and are typically mixed with binders, pore-formers, extrusion aids, and fluid to form a homogeneous extrudable mass. The homogeneous mass is extruded into a green substrate. The more volatile material is preferentially removed from the green substrate, which allows the fibers to form interconnected networks.

Abstract: A porous substrate produced by an extrusion process consisting essentially of bonded fibers is fabricated as a segmented substrate by joining a plurality of substrate segments with an adhesive that comprising fibers. The adhesive is bonded to fibers in the substrate segments to provide mechanical strength of the segmented substrate. The fibers in the adhesive provide a reduced elastic modulus in the adhesive layer that maintains a highly elastic structure between the segments in order to mitigate thermally induced mechanical stress when thermal gradients develop within the porous substrate during operation. The segmented porous fibrous substrate disclosed can be fabricated from a variety of materials to provide for effective filtration and as a catalytic host in various applications, including exhaust filtration of internal combustion engines.