Abstract:
A method to produce a self-supporting ceramic structure by oxidation of a liquid phase parent metal with a vapor phase oxidizing environment includes applying a layer having at least one dopant material to at least a portion of a parent metal of the type having an oxide skin which is normally impervious to an oxiding atmosphere. Upon temperature elevation, the parent metal becomes molten and due to the dopant material in the layer, is caused to migrate through the oxide skin and layer so as to be exposed to the oxidizing atmosphere whereupon an oxide of the parent metal is formed. Migration of the parent metal continues through the formed parent metal oxide to grow layer upon layer of parent metal oxide to thus achieve a self-supporting oxide structure.
Abstract:
The present invention relates to novel ceramic-filled metal matrix composites and methods for making the same. Particularly, a permeable mass of filler material is spontaneously infiltrated by, for example, an aluminum alloy, in the presence of nitrogen-containing atmosphere. A reservoir feeding technique for forming metal matrix composite bodies is also disclosed. The reservoir feeding technique can also be used to form complex (e.g., a metal bonded to a metal matrix composite) metal matrix composite bodies.
Abstract:
The present invention relates to the formation of a macrocomposite body by spontaneously infiltrating a permeable mass of filler material or a preform (4) with molten matrix metal (2) and bonding the spontaneously infiltrated material to at least one second material such as a ceramic or ceramic containing body and/or a metal or metal containing body. Particularly, an infiltration enhancer and/or infiltration enhancer precursor and/or infiltrating atmosphere are in communication with a filler material or a preform (4), at least at some point during the process, which permits molten matrix metal (2) to spontaneously infiltrate the filler material or preform (4). Moreover, prior to infiltration, the filler material or preform (4) is placed into contact with at least a portion of a second material such that after infiltration of the filler material or preform (4), the infiltrated material is bonded to the second material, thereby forming a macrocomposite body.
Abstract:
The present invention relates to the formation of a metal matrix composite body by a spontaneous infiltration technique and thereafter thermo-forming the produced metal matrix composite body. Particularly, an infiltration enhancer and/or an infiltration enhancer precursor and/or an infiltrating atmosphere are in communication with a filler material (2) or a preform, at least at some point during the process, which permits molten matrix metal to spontaneously infiltrate the filler material (2) or preform. After formation of the metal matrix composite body, the body is subjected to a thermo-forming technique such as rolling, extruding, die casting, pressing, etc.
Abstract:
A complex oxidation reaction product of two or more metals in an oxidized state is formed by positioning a suitable precursor metal (1) adjacent to a permeable mass (2) of a metal-containing compound in an oxidizing atmosphere and heating the assembly to form a body of molten precursor metal. The molten metal infiltrates the permeable mass (2) and reacts therewith and with the oxidizing atmosphere to form a complex oxidation reaction product. Methods for determining the shape of the resulting article are described. The disclosed methods can be used to form superconducting perovskites.
Abstract:
The present invention provides a method for producing a self-supporting ceramic composite by the oxidation of a parent metal (10) to form a polycrystalline ceramic material consisting essentially of the oxidation reaction product of the parent metal (10) with an oxidant, including a vapor-phase oxidant, and, optionally, one or more metallic constituents. A permeable filler material, such as a preform (14), with at least one surface bearing a permeble stratum (18), is contacted with a body of molten parent metal (10) heated to a temperature above its melting point but below the melting point of the oxidation reaction product. At least a portion of the oxidation reaction product is maintained in contact with and between the molten metal (10) and oxidant to transport the molten metal through the oxidation reaction product toward the permeable stratum (18) and into contact with the oxidant so that the oxidation reaction product continues to form at the interface between the oxidant and previously formed oxidation reaction product that has infiltrated the filler material. The reaction is continued to infiltrate at least a portion of the stratum (18) with the oxidation reaction product and to produce an intermediate ceramic body having an adjacent ceramic composite overlaid with a ceramic stratum. The ceramic stratum is removed from the underlying ceramic composite to produce a self-supporting ceramic composite having the surface established by the permeable stratum (18).