摘要:
This invention relates generally to the fabrication of materials for use as tools in various applications. Specific emphasis is placed upon certain ceramic matrix composite materials and metal matrix composite materials for use as tools as well as certain ceramic matrix composite and/or metal matrix composite coatings on substrate materials, also for use as tools. This invention makes specific reference to a number of different materials for use as tools in the molding of thermoplastic materials (e.g., polymers, plastics, ceramics, glasses, metals) with particular emphasis being directed to the thermoplastic molding of plastics or polymers.
摘要:
In the present invention, there is described a setup for producing a self-supporting ceramic body or ceramic composite by the oxidation of a parent metal to form a polycrystalline ceramic material comprising the oxidation reaction product of said parent metal with an oxidant, including a vapor-phase oxidant, and optionally one or more metallic constituents dispersed throughout the polycrystalline ceramic material. The setup is used with a method which comprises the steps of providing at least a portion of said parent metal with a barrier means at least partially spaced from said parent metal for establishing at least one surface of the ceramic body, and heating said parent metal to a temperature above its melting point but below the melting point of the oxidation reaction product to form a body of molten metal. At that temperature, the molten metal is reacted with the oxidant, thus forming the oxidation reaction product. At least a portion of the oxidation reaction product is maintained in contact with and between the molten metal and oxidant to transport the molten metal through the oxidation reaction product toward the barrier means and into contact with fresh oxidant so that the oxidation reaction product continues to form at an interface between the oxidant and previously formed oxidation reaction product. The reaction is continued until the oxidation reaction product contacts the barrier means to produce a ceramic body having the surface established by the barrier means. A shaped ceramic composite is formed by superimposing a barrier means onto either a loose mass of filler material or a self-supporting preform and infiltrating the mass of filler or preform with the polycrystalline ceramic matrix, which grows until it contacts the barrier means.
摘要:
In the present invention there is provided a method for producing a self-supporting ceramic or ceramic composite body by the oxidation of a parent metal to form a polycrystalline ceramic material comprising the oxidation reaction product of said parent metal with an oxidant, including a vaporphase oxidant, and optionally one or more metallic constituents dispersed throughout the polylcrystalline ceramic material. The method comprises the steps of providing at least a portion of said parent metal for establishing at least one surface of the ceramic body, and heating said parent metal to a temperature above its melting point but below the melting point of the oxidation reaction product to form a body of molten metal. At that temperature, the molten metal is reacted with the oxidant, thus forming the oxidation reaction product. At least a portion of the oxidation reaction product is maintained in contact with and between the molten metal and oxidant to transport the molten metal through the oxidation reaction product toward the barrier means and into contact with the oxidant so that fresh oxidation reaction product continues to form at an interface between the oxidant and previously formed oxidation reaction product. The reaction is continued until the oxidation reaction product contacts the barrier means to produce a ceramic body having the surface established by the barrier means. A shaped ceramic composite is formed by superimposing a barrier means onto either a loose mass of filler material or a self-supporting preform, and infiltrating the mass of filler or preform with the polycrystalline ceramic matrix, which grows until it contacts the barrier means.
摘要:
Self-supporting ceramic composite bodies of desired shape are produced by infiltrating a permeable self-supporting preform with polycrystalline matrix material comprising an oxidation reaction product obtained by oxidation of a parent metal precursor, such as aluminum, and optionally containing therein metallic constituents. The composite body is formed by contacting a zone of a permeable self-supporting preform, having at least one defined surface boundary spaced from said contacting zone, with a body of molten metal which is reacted with a suitable vapor-phase oxidant to form an oxidation reaction product. Within a certain temperature region, and optionally with one or more dopants in or on the parent metal or said permeable preform, molten parent metal migrates through previously formed oxidation reaction product into contact with the oxidant, causing the oxidation reaction product to grow into the preform toward said defined surface boundary so as to infiltrate the preform up to said defined surface boundary with the oxidation reaction product, thus providing the composite structure of desired geometry.
摘要:
A self-supporting ceramic body having a polymer component, which includes first providing a self-supporting ceramic body comprising (i) a polycrystalline oxidation reaction product formed upon oxidation of a molten parent metal with an oxidant, and (ii) interconnected porosity at least partially accessible from one or more surfaces of said ceramic body. The polymer is disposed or formed within the interconnected porosity. The polymer is situated so as to alter, modify or contribute to the properties of the ceramic body originally formed.
摘要:
A method for producing a self-supporting ceramic composite structure comprising a ceramic matrix embedding a filler, includes oxidizing a parent metal to form a polycrystalline material comprising the oxidation reaction product of the parent metal and, optionally, one or more metallic constituents. The method includes heating the parent metal to provide a source of molten parent metal and a reservoir of molten metal which is in communication with the parent metal and contacting the molten parent metal with a permeable bedding of filler. The molten parent metal reacts with the oxidant to form the oxidation reaction product and is replenished by the reservoir as the reacting continues for a time sufficient to grow the oxidation reaction product to a desired extent and thereby embed at least a portion of the bedding of filler within the oxidation reaction product to form the ceramic composite structure. The bedding of filler may have any suitable shape, including that of a hollow body, the interior of which is contacted by the molten parent metal to grow the oxidation reaction product through the shaped, hollow body of filler.
摘要:
A self-supporting ceramic composite body produced by a method body which comprises preparing a polycrystalline material as the oxidation reaction product of a parent metal with a vapor-phase oxidant, comminuting the resulting material to a particulate, forming a permeable mass of said particulate as filler, and infiltrating said particulate with an oxidation reaction product of a parent metal with a vapor-phase oxidant, thereby forming said ceramic composite body.
摘要:
A method of producing self-supporting ceramic or ceramic composite bodies having a polymer component, which includes first providing a self-supporting ceramic or ceramic composite body comprising (i) a polycrystalline oxidation reaction product formed upon oxidation of a molten parent metal with an oxidant, and (ii) interconnected porosity at least partially accessible from one or more surfaces of said ceramic body. The polymer is disposed or formed within the interconnected porosity. The polymer is situated so as to alter, modify or contribute to the properties of the ceramic or ceramic composite body originally formed.
摘要:
Two or more ceramic bodies are bonded together by oxidizing with a vapor-phase oxidant molten metal obtained from a body of precursor metal to form an oxidation reaction product bond. The oxidation reaction product is formed between adjacent facing, substantially congruent surfaces of the ceramic bodies and bridges the surfaces, thus bonding the ceramic bodies to each other. Promoters may optionally be used to facilitate formation of the oxidation reaction product.
摘要:
In the present invention there is provided a method for producing abrasive ceramic and ceramic composite material characterized by an abrasive grain as the comminuted form of a polycrystalline ceramic material. The abrasive grains of the present invention consist essentially of the oxidation reaction product of a parent metal precursor with a vapor phase oxidant, and, optionally one or more metallic constituents such as non-oxidized constituents of the parent metal. There is also provided a method for producing abrasive grains which additionally consist of one or more inert filler materials.