Abstract:
A method of producing self-supporting ceramic structures (12) comprising (i) a polycrystalline oxidation reaction product formed upon oxidation of a molten parent metal (14) with an oxidant, and (ii) interconnected porosity (13) at least partially accessible from one or more surfaces (15) of said ceramic body. A second polycrystalline ceramic material is incorporated into the porosity of said ceramic body to modify or contribute to its properties.
Abstract:
A method of producing a composite comprising a self-supporting polycrystalline material obtained by oxidation reaction of a molten parent metal (2) with a vapor-phase oxidant comprising infiltrating a filler (3) exhibiting inter-particle pore volume with a parent metal (2) under conditions which control the respective rates of said metal infiltration and said oxidation reaction.
Abstract:
The invention comprises a method of making self-supporting composite ceramic structures by the oxidation reaction of a body of molten parent metal precursor with a vapor-phase oxidant to form an oxidation reaction product. This reaction or growth is continued to form a thick, self-supporting ceramic body. The composite is recovered and in a separate subsequent operation, the surface is coated with one or more materials in order to effect desired changes in the properties of the surface, e.g., hardness, corrosion resistance.
Abstract:
In the present invention, there is provided a method for producing a self-supporting ceramic body by the oxidation of a parent metal to form a polycrystalline ceramic material consisting essentially of the oxidation reaction product of said parent metal with an oxidant, including a vapor-phase oxidant, and optionally one or more metallic constituents. The method 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 the oxidant so that the oxidation reaction product continues to form at the interface between the oxidant and previously formed oxidation reaction product optionally leaving metal dispersed through the polycrystalline material. The reaction is continued to the barrier means to produce a ceramic body having the surface established by the barrier means. A composite is formed by superimposing a barrier onto a filler material, such as a preform, and infiltrating the filler with the polycrystalline ceramic matrix grown to the barrier means.
Abstract:
Ceramic bodies may be prepared using a combination of thin structure formation techniques and metal oxidation techniques. Specifically, a thin form is provided comprising at least one parent metal, at least one organic or inorganic fiber, and optionally comprising at least one inorganic filler material. The thin form may then be infiltrated with a liquid or fusible composition such as a polyureasilazane to increase the flexibility and formability of the thin form. The thin form may then be shaped or configured, either individually or in stacks, and rigidized to form for example, a self-supporting structure. The thin form may then be heated to a temperature above the melting point of the parent metal to react the molten parent metal in situ with an oxidant to form an oxidation reaction product, which is at least partially three-dimensionally interconnected to form a thin ceramic body in a desired shape or configuration.
Abstract:
The present invention relates to the formation of a macrocomposite body for use as an electronic package or container. The macrocomposite body is formed by spontaneously infiltrating a permeable mass of filler material (247) or a preform with molten matrix metal (250) 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. Moreover, prior to infiltration, the filler material or preform is placed into contact with at least a portion of a second material such that after infiltration of the filler material or preform by molten matrix metal, the infiltrated material is bonded to said second material, thereby forming a macrocomposite body. The macrocomposite body may then be coated by techniques according to the present invention to enhance its perfomance and/or bonding capabilities.
Abstract:
The present invention relates to a novel process for forming metal matrix composite bodies by using a barrier material. Particularly, an infiltration enhancer and/or an infiltration enhancer precursor and/or an infiltrating atmosphere are in communication with a filler material or a preform, at least at some point during the process, which permits molten matrix metal to spontaneously infiltrate the filler material or preform up to the barrier material. Such spontaneous infiltration occurs without the requirement for the application of any pressure or vaccum. Accordingly, shaped metal matrix composite bodies can be produced having superior surface finish.
Abstract:
The present invention relates to the formation of bodies having graded properties. Particularly, the invention provides a method for forming a metal matrix composite body having graded properties. The graded properties are achieved by, for example, locating differing amounts of filler material in different portions of a formed body and/or locating different compositions of filler material in different portions of a formed body and/or locating different sizes of filler materials in different portions of a formed body. In addition, the invention provides for the formation of macrocomposite bodies wherein, for example, an excess of matrix metal can be integrally bonded or attached to a graded metal matrix composite portion of a macrocomposite body.
Abstract:
This invention relates to metal and metal matrix composite materials that are useful as, for example, brake rotors, clutch plates and other similar uses which benefit from material properties of the invention. In the case of metal matrix composite materials, clutch plates and brake rotors made according to the invention comprise an interconnected matrix metal embedding at least one filler material. For example, the at least one filler material comprises numerous acceptable filler materials present in a sufficient quantity to provide desired performance. The brake rotors and clutch plates according to the invention further comprise a coating on the surface thereof causing the metal or metal matrix composite body to function as a substrate. The coatings may be applied by various conventional techniques. Desirable results of placing a coating on a metal or metal matrix composite substrate brake rotor or clutch plate include a significant increase in the maximum operating temperature of the brake rotor or clutch plate and/or a significant reduction in weight in comparison to conventional materials, etc.