Abstract:
This invention relates generally to a novel method of preparing self-supporting bodies, and novel products made thereby. In its more specific aspects, this invention relates to a method for producing self-supporting bodies comprising one or more boron-containing compounds, e.g., a boride or a boride and a carbide, by reactive infiltration of molten parent metal into a preform comprising boron carbide or a boron donor material combined with a carbon donor material and, optionally, one or more inert fillers, to form the body. Specifically, a boron carbide material or combination of a boron donor material and a carbon donor material, and in either case, optionally, one or more inert fillers, are sedimentation cast, slip cast or pressed onto or into a body and into a particular desired shape.
Abstract:
This invention relates generally to a novel method of manufacturing a composite body, such as a ZrB.sub.2 -ZrC-Zr (optional) composite body, by utilizing a post-treatment process and to the novel products made thereby. More particularly, the invention relates to a method of modifying a composite body comprising one or more boron-containing compounds (e.g., a boride or a boride and a carbide) which has been made by the reactive infiltration of a molten parent metal into a bed or mass containing boron carbide, and optionally one or more inert fillers, to form the body.
Abstract:
Self-supporting bodies are produced by reactive infiltration of a parent metal into a boron carbide material which may contain one or both of a boron donor material and a carbon donor material. The reactive infiltration typically results in a composite comprising a boron-containing compound, a carbon-containing compound and residual metal, if desired. The mass to be infiltrated may contain one or more inert fillers admixed with the boron carbide material, boron-containing compound and/or carbon-containing compound. The relative amounts of reactants and process conditions may be altered or controlled to yield a body containing varying volume percents of ceramic, metal, ratios of one ceramic to another and porosity.
Abstract:
This invention relates generally to a novel method of manufacturing a composite body and to novel products made thereby. More particularly, the invention relates to a method of producing a self-supporting body comprising one or more boron-containing compounds, e.g., a boride or a boride and carbide, by reactive infiltration of molten parent metal into a bed or mass containing boron carbide, and, optionally, one or more inert fillers and permitting residual or excess parent metal, to remain bonded to the formed self-supporting body. Excess metal is used to form a bond between the reactively infiltrated body and another body (e.g., a metal or a ceramic body).
Abstract:
A method of producing a composite comprising a self-supporting polycrystalline material obtained by oxidation reaction of a molten parent metal with a vapor-phase oxidant comprising infiltrating a filler exhibiting inter-particle pore volume with a parent metal under conditions which control the respective rates of said metal infiltration and said oxidation reaction.
Abstract:
Self-supporting bodies are produced by reactive infiltration of a parent metal into a boron nitride material typically resulting in a body comprising a boron-containing compound, a nitrogen-containing compound and metal. The mass to be infiltrated may contain one or more inert fillers admixed with the boron nitride, to produce a composite by reactive infiltration, which composite comprises a matrix which embeds the filler material. The matrix, in a composite body containing filler material, comprises one or more of metal, a boron-containing compound and a nitrogen-containing compound. The relative amounts of reactants and process conditions may by altered or controlled to yield a body containing varying volume percents of ceramic, metal and/or porosity. The mass to be infiltrated can be contained within a refractory vessel having a venting means included therein.
Abstract:
Self-supporting bodies are produced by reactive infiltration of a parent metal into boron carbide typically resulting in a composite comprising a boron-containing compound and metal. The mass to be infiltrated may contain one or more inert fillers admixed with the boron carbide, or at least one carbon donor material, to produce a composite by reactive infiltration, which composite comprises a matrix of metal and boron-containing compound embedding the filler. In one embodiment of the invention, a parent metal is reactively infiltrated into a mass comprising a boron carbide material mixed with a carbon-containing compound. In this embodiment, a self-supporting composite is formed typically comprising a boron-containing compound, a carbon-containing compound, and metal. The relative amounts of reactants and process conditions may be altered or controlled to yield a body containing varying volume percents of ceramic, metal and/or porosity. The mass to be infiltrated can be contained within a refractory vessel having a venting means included therein.
Abstract:
A high-temperature direct-contact thermal energy storage element for use in a system for storage and retrieval of thermal energy in the range of about 400.degree. to about 2000.degree. F. The thermal energy is directly stored, without heat exchange tubes in composite latent/sensible heat thermal energy storage media utilizing the heat of fusion and high-temperature stability of alkaline metal and alkaline earth carbonates, chlorides, nitrates, nitrites, fluorides, hydroxides, sulfates, and mixtures thereof maintained within a porous support-structure material which itself is capable of storage as sensible heat. The thermal energy storage according to the invention may be effectively utilized for storage of thermal energy derived from solar, industrial waste, process heat, and high-temperature gas reactor energy sources and retrieved for a wide variety of uses such as combustion air preheating, drying, space heating, heating of process gases, and the like.
Abstract:
A net shaped ceramic-reinforced aluminum matrix composite is provided by forming a permeable mass of ceramic material with a defined surface boundary having a barrier, and contacting a molten aluminum-magnesium alloy with the permeable mass of ceramic material in the presence of a gas comprising from about 10 to 100% nitrogen, by volume, balance nonoxidizing gas, e.g. hydrogen or argon. Under these conditions, the molten alloy spontaneously infiltrates the ceramic mass under normal atmospheric pressures until it reaches the barrier. A solid body of the alloy can be placed adjacent to a permeable bedding of ceramic material having a barrier, and brought to the molten state, preferably to at least about 700.degree. C., in order to form the net shape aluminum matrix composite by spontaneous infiltration. In addition to magnesium, auxiliary alloying elements may be employed with aluminum. The resulting composite products may contain a discontinuous aluminum nitride phase in the aluminum matrix.
Abstract:
A method of making self-supporting ceramic composite structures having filler embedded therein includes infiltrating a permeable mass of filler with polycrystalline material comprising an oxidation reaction product obtained by oxidation of a parent metal such as aluminum and optionally, containing therein non-oxidized constituents of the parent metal. The structure is formed by placing a parent metal adjacent to a permeable filler and heating the assembly to melt the parent metal and provide a molten body of parent metal which is contacted with a suitable vapor-phase oxidant. Within a certain temperature region and optionally, aided by one or more dopants in or on the parent metal, molten parent metal will migrate through previously formed oxidation reaction product into contact with the oxidant, causing the oxidation reaction product to grow so as to embed the adjacent filler and provide the composite structure. In a preferred embodiment, a parent metal comprising aluminum is oxidized by a vapor-phase oxidant comprising nitrogen to form a ceramic matrix comprising an aluminum nitride oxidation reaction product. In a particularly preferred embodiment, one or more protective coatings are applied to the filler prior to formation of the aluminum nitride oxidation reaction product matrix.