摘要:
The present invention relates to modified geopolymer compositions, geopolymer-coated organic polymer substrates, and methods of manufacturing and articles comprising same.
摘要:
A porous discriminating layer is formed on a ceramic support having at least one porous wall by (a) establishing a flow of a gas stream containing agglomerates of particles and (b) calcining said deposited layer to form the discriminating layer. At least a portion of the particles are of a sinter-resistant material or a sinter-resistant material precursor. The particles have a size from 0.01 to 5 microns and the agglomerates have a size of from 10 to 200 microns. This method is an inexpensive and effective route to forming a discriminating layer onto the porous wall.
摘要:
An improved ceramic honeycomb structure is comprised of at least two separate smaller ceramic honeycombs that have been adhered together by a cement layer comprised of a cement layer has at least two regions of differing porosity or cement layer where the ratio of toughness/Young's modulus is at least about 0.1 MPa·m1/2/GPa.
摘要:
An improved aluminum-boron carbide (ABC) composite has been discovered that is comprised of a continuous network of AlB24C4 and boron carbide grains having therein other isolated aluminum-boron carbide reactive phases and at most 2% by volume of isolated metal. The improved ABC composite may be formed by forming boron carbide particulates into a porous body that has a porosity of at most about 35%, where the boron particulates have been heat treated to a temperature of 1200° C. to 1800° C., infiltrating the porous body with aluminum or aluminum alloy until an infiltrated aluminum-boron carbide body is formed that has at most about 1% porosity, heat treating the infiltrated body for at least 25 hours at 1000° C. to 1100° C. to form an aluminum boron carbide composite having a continuous network of AlB24C4 and boron carbide, and subsequently heat-treating to 700° C. to 900° C. to form the improved aluminum boron carbide composite.
摘要:
A method of forming a porous mullite composition of acicular mullite grains having improved properties is described, where the mullite is formed at some time in the presence of a fluorine containing gas. For example, it has been discovered that improved properties may result from heating the mullite to a high temperature in an atmosphere selected from the group consisting of water vapor, oxygen, an inert gas or mixtures thereof or forming the mullite composition from precursors having an Al/Si ratio of at most 2.95.
摘要:
A concrete article comprised of concrete having therein a reinforcing fiber, where at least about 50 percent of the reinforcing fibers are frayed only at an end or ends of the reinforcing fibers, may be made by mixing concrete, water and a reinforcing fiber for a sufficient time to fray the ends of at least 50 percent of the fibers and curing the mixture to form the concrete article. The fiber may be a reinforcing fiber comprised of at least two filaments bonded together and the filaments being comprised of a polymeric core and a polymeric sheath comprised of a fusing-fraying polymer, such that the reinforcing fiber, when mixed with inorganic particulates, frays predominately only at an end or ends of the fiber.
摘要:
A concrete article is prepared by mixing concrete, water and a reinforcing polymer comprised of a substantially random interpolymer of at least one &agr;-olefin, with at least one vinyl or vinylidene aromatic monomer and curing said concrete mixture to form a concrete article having the reinforcing polymer therein, such that the reinforcing polymer has a surface comprised of the substantially random interpolymer in contact with the concrete.
摘要:
A ceramic-metal composite that is tough and stiff has been prepared and is comprised of an inert ceramic (e.g., alumina) embedded and dispersed in a matrix comprised of a metal (e.g., aluminum), a reactive ceramic (e.g., boron carbide) and a reactive ceramic-metal reaction product (e.g., AlB2, Al4BC, Al3B48C2, AlB12, Al4C3, AlB24C4 or mixtures thereof) wherein grains of the inert ceramic have an average grain size greater than or equal to the average grain size of grains of the reactive ceramic. The ceramic-metal composite may be prepared by forming a mixture comprised of an inert ceramic powder (e.g., alumina) and a reactive ceramic powder (e.g., boron carbide), the inert ceramic powder having an average particle size equal to or greater than the average particle size of the reactive ceramic powder, forming the mixture into a porous body and consolidating the porous body in the presence of a metal (e.g., aluminum) to form the ceramic-metal composite.
摘要:
A braking component such as a brake pad, brake rotor, brake drum or clutch disk is comprised of a metal substrate having a friction material laminated on at least a portion of at least one face of the metal substrate, the friction material being a ceramic-metal composite comprised of a metal phase and a ceramic phase dispersed within each other, wherein the ceramic phase is present in an amount of at least about 20 percent by volume of the ceramic-metal composite. In particular, the braking component is a metal substrate, such as aluminum, having laminated thereto a ceramic-metal composite of a dense boron carbide-aluminum composite having high specific heat and low density.
摘要:
A process for preparing complex-shaped, ceramic-metal composite articles, comprising: (a) contacting a non-wettable powder that is non-wetting to a metal to be used for infiltration with a shaped ceramic body to form a layer of the non-wettable powder on one or more surfaces of the shaped ceramic body, wherein the shaped ceramic body has a region where there is no layer of the non-wettable powder, and (b) infiltration the shaped ceramic body with the metal through the region or regions where there is no layer of the non-wettable powder, such that a complex-shaped ceramic-metal composite comprising one or more metal phases and one or more ceramic phases is formed, wherein the article has substantially the net shape of the shaped ceramic body and undesirable regions of excess metal on the surface and undesirable phases within the complex-shaped ceramic-metal composite article near the surface are located only in the region or regions where there is no layer of the non-wettable powder. The process of the invention allows the preparation of complex-shaped ceramic-metal composite articles with undesirable regions of excess metal and undesirable phases on the surface(s), of, or within, the article only in the regions where there is, or was, no layer of non-wettable powder. The process of the invention allows the preparation of a complex-shaped ceramic-metal composite article which requires little or no machining of the surface(s) to achieve a finished article. A complex-shaped ceramic-metal composite article is prepared which contains few undesirable regions of excess metal and undesirable phases.