Abstract: The invention relates to a method that involves (a) removing graphite from at least one surface of a metal graphite composite material; (b) chemically cleaning or plasma etching the surface of the metal graphite composite material; (c) applying a metal-containing material to the surface of the chemically cleaned or plasma etched metal graphite composite material, and thereby forming an intermediate layer; (d) applying a metal coating on the intermediate layer, and thereby forming a composite material. The invention also relates to a composite material comprising (a) a metal graphite composite substrate having at least one surface that is substantially free of graphite; (b) a metal-containing intermediate layer located on a surface of the substrate; and (c) a metal coating on the intermediate layer.

Abstract: Methods and materials for preparing investment molds useful in pressure infiltration casting of near net-shape metal or metal matrix composite (MMC) components. One embodiment of the invention includes disposing a slurry of an appropriately sized refractory material and a vehicle around a preform or fugitive pattern, removing the bulk of the vehicle, then curing/drying the refractory material to create an investment mold of the invention. Subsequently, pressure infiltration casting with a molten infiltrant using the investment mold permits infiltration of the mold cavity and/or preform without infiltration of the investment mold. As a result, the investment mold readily is removed to provide the near net-shape metal or MMC component. In other embodiments of the invention, a non-fugitive pattern is used, typically with a modified refractory cement of the invention.

Abstract: Disclosed are economical methods and apparatus for high throughput pressure infiltration casting. Methods of the invention use a mold vessel as an evacuation chamber along with an evacuation cap to produce superior quality near-net shape finished cast parts with low porosity. Other methods of the invention use an improved heat transfer technique for directionally solidifying molten infiltrant at an increased rate to increase further the throughput of the pressure infiltration casting cycle. The invention also provides apparatus for practicing methods for high throughput pressure infiltration casting. One embodiment of an apparatus of the invention is a removable evacuation cap, often used in conjunction with a fill tube. Another apparatus embodiment is an evacuation cap coupled to a mold vessel which is used as an evacuation chamber.

Abstract: A mold cavity in a mold vessel is evacuated. A charge of molten infiltrant is transported into the mold vessel while the vacuum is maintained in the mold cavity. Pressure is applied to the molten infiltrant to move the molten infiltrant from the mold vessel into the mold cavity. The molten infiltrant is cooled in the mold cavity to solidify the infiltrant. A fill tube can be used to transport the infiltrant to the mold vessel.