A ceramic-reinforced aluminum matrix composite is formed by contacting a molten aluminum-magnesium alloy with a permeable mass of ceramic material in the presence of a gas comprising from about 10 to 100% nitrogen, by volume, balance non-oxidizing gas, e.g., hydrogen or argon. Under these conditions, the molten alloy spontaneously infiltrates the ceramic mass under normal atmospheric pressures. A solid body of the alloy can be placed adjacent a permeable bedding of ceramic material, and brought to the molten state, preferably to at least about 700° C., in order to form the aluminum matrix composite by 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 and/or an aluminum nitride external surface layer.

Metal matrix composites

Shaped, preferably porous, inorganic bodies are provided which are prepared from a reactive blend. In accordance with one preferred embodiment, the solution is absorbed into a porous sacrificial substrate such as a cellulose sponge. The solution-saturated substrate is heated and an oxidation-reduction reaction occurs thereby forming an inorganic solid. A shaped, inorganic body is formed in situ. Optional, but preferred additional thermal treatment of the shaped, inorganic body removes the organic substrate, leaving an inorganic body that faithfully mimics the porosity, shape, and other physical characteristics of the organic substrate. Inorganic substrates may also be used to good effect. Large varieties of shaped bodies can be prepared in accordance with other embodiments of the invention and such shapes find wide use in surgery, laboratory and industrial processes and otherwise. The invention also provides chemically and morphologically uniform powders, including those having uniformly small sizes.

Inorganic shaped bodies and methods for their production and use

Shaped, composite bodies are provided. One portion of the shaped bodies comprises an RPR-derived porous inorganic material, preferably a calcium phosphate. Another portion of the composite bodies is a different solid material, preferably metal, glass, ceramic or polymeric. The shaped bodies are especially suitable for orthopaedic and other surgical use.

Composite shaped bodies and methods for their production and use

A multi-layered ceramic tube (Figure 1) to contain fissile fuel within a nuclear power reactor, particularly as cladding layer for a fuel rod in a nuclear power plant or reactor, having an inner layer (20) of high purity beta phase stoichiometric silicon carbide, a central composite layer (22) of continuous beta phase stoichiometric silicon carbide fibers, and an outer layer (24) of fine-grained silicon carbide, to improve initial crack resistance, stiffness, ultimate strength, impact resistance and thermal shock resistance.

Multi-layered ceramic tube for fuel containment barrier and other applications in nuclear and fossil power plants

A semiconductor memory device comprises memory cells, a bitline connected to the memory cells, a read circuit including a precharge circuit, and a first transistor connected between the bitline and the read circuit, wherein a first voltage is applied to a gate of the first transistor when the precharge circuit precharges the bitline, and a second voltage which is different from the first voltage is applied to the gate of the first transistor when the read circuit senses a change in a voltage of the bitline.

Semiconductor memory device.

A method for bonding aluminum and aluminum alloys to refractory materials. A body of metal is heated to an elevated temperature at a total pressure above the vapor pressure of aluminum but less than atmospheric pressure. Oxygen partial pressure is maintained sufficiently low to prevent substantial oxidation of the metal. The heated body is contacted with a mass of refractory material and cooled, thereby forming a composite.

Bonding aluminum to refractory materials

A method of forming fiber reinforced aluminum phosphate bonded material having improved strength at elevated temperatures. The method comprises the steps of: (a) preparing a slurry by blending alumina and alumina phosphate solution, the slurry being substantially free of silica; (b) providing a fiber substrate; (c) infiltrating the solution into the fiber substrate; and (d) curing the infiltrated substrate to form a fiber reinforced aluminum phosphate bonded composite material. In a preferred embodiment of the present invention, the fiber substrate is made from SiC fibers.

Donald J. Bray

Papers

Bonding aluminum to refractory materials

Fiber reinforced composite having an aluminum phosphate bonded matrix

Thermochemical Characterization of SiC Whiskers in A12O3 Matrices