摘要:
A carbonaceous material coated with a molybdenum carbide coating, the molybdenum carbide coating protecting the carbonaceous material against attack by molten metal while simultaneously providing a wetting action for the molten metal to infiltrate the carbonaceous material. The carbonaceous material is any suitable carbonaceous material such as diamond; graphite fibers, both continuous and discontinuous; carbon and graphite particulate; lampblack; and carbon-rich surfaces. The molybdenum carbide coating is produced by reacting a gaseous molybdenum compound with the surface of the carbonaceous material under a reducing atmosphere. The molybdenum carbide coated carbonaceous material is formed into a metal/carbonaceous material composite by being heated with the metal under an inert atmosphere until the molten metal infiltrates the molybdenum carbide coated carbonaceous material. The metals include copper, aluminum, magnesium, iron, nickel, cobalt, titanium, silver, gold, platinum, rhodium, tin, zinc, and alloys of these metals.
摘要:
A fiber coating which allows ceramic or metal fibers to be wetted by molten metals is disclosed. The coating inhibits degradation of the physical properties caused by chemical reaction between the fiber and the coating itself or between the fiber and the metal matrix. The fiber coating preferably includes at least a wetting layer, and in some applications, a wetting layer and a barrier layer between the fiber and the wetting layer. The wetting layer promotes fiber wetting by the metal matrix. The barrier layer inhibits fiber degradation. The fiber coating permits the fibers to be infiltrated with the metal matrix resulting in composites having unique properties not obtainable in pure materials.
摘要:
A novel heat transfer apparatus and method including a body of carbon/carbon material with cooling tubes brazed therein. The carbon/carbon material includes carbon, graphite, carbon fibers, graphite fibers and combinations of the same and silicon carbide and boron carbide. The cooling tubes are prepared from stainless steel, nickel and its alloys, cobalt and its alloys, copper, molybdenum, molybdenum rhenium alloy, and carbon. A wetting agent is applied to the carbon surfaces to protect the carbon surfaces from attack by the molten brazing material and is selected from molybdenum niobium, tantalum, tungsten, and carbides of these refractory metals. The brazing material is selected from copper, copper alloys, silver, and gold. Advantageously, the wetting agent not only protects the carbon surfaces from attack by the brazing metals but its surface tension therewith holds the brazing metal into intimate thermal contact between the carbon surface and the cooling tubes even while the novel heat transfer apparatus of this invention is operating at temperatures above the melting temperature of the brazing metal.
摘要:
A composite of a metal infiltrated into a carbonaceous material. The carbonaceous material is coated with a molybdenum carbide coating, the molybdenum carbide coating protecting the carbonaceous material against attack by molten metal while simultaneously providing a wetting action for the molten metal to infiltrate the carbonaceous material. The carbonaceous material is any suitable carbonaceous material such as diamond; graphite fibers, both continuous and discontinuous; carbon and graphite particulate; lampblack; and carbon-rich surfaces. The molybdenum carbide coating is produced by reacting a gaseous molybdenum compound with the surface of the carbonaceous material under a reducing atmosphere. The molybdenum carbide coated carbonaceous material is formed into a metal/carbonaceous material composite by being heated with the metal under an inert atmosphere until the molten metal infiltrates the molybdenum carbide coated carbonaceous material. The metals include copper, aluminum, magnesium, iron, nickel, cobalt, titanium, silver, gold, platinum, rhodium, tin, zinc, and alloys of these metals. The composite exhibits a high degree of thermal and electrical conductivity and a low coefficient of thermal expansion.
摘要:
A method for producing a composite having graphite fibers in a matrix of copper/copper alloy. The graphite fibers are coated with a refractory metal which both protects the graphite fibers from the molten copper/copper alloy while also acting as a wetting agent on the graphite fibers for intimate infiltration by the molten copper/copper alloy. The coated graphite fibers are prepared in a structure and placed against a copper/copper alloy element which is melted to produce the molten copper/copper alloy. The infiltration of the graphite fiber structure with the molten copper/copper alloy is characterized by the absence of pressure on the molten copper/copper alloy.
摘要:
A dual axis bioreactor system wherein a bioreactor vessel is mounted at its longitudinal axis to a horizontal axle with the bioreactor vessel thereby being rotatable about its longitudinal axis. The horizontal axle is rotatably mounted to a vertical shaft with the vertical shaft rotating the horizontal axle in a horizontal plane. A gear system limits the rotation of the bioreactor vessel to one rotation about its longitudinal axis for each revolution of the bioreactor vessel about the vertical shaft. A flexible, multilumen conduit is affixed to the base of the bioreactor vessel at the longitudinal axis to provide fluid communication with the bioreactor vessel. The rotation rate of the vertical shaft is carefully controlled to reduce any centrifugation effects upon the contents in the bioreactor vessel while providing mixing therein. The bioreactor system is ideally suited for continuous flow reactions and is particularly advantageous in that it eliminates moving seals, openings, or other possible sources of contamination.