Georgia Tech Research Corporation

Walter J Lackey

John A Hanigofsky

William Brent Carter

David N Hill

E Kent Barefield

Stuart R Stock

Michael J Shapiro

Sundar Vaidyaraman

A laminated matrix composite made of a reinforcement phase and coated with several layers of a metallic, ceramic, or polymeric matrix material, the average thickness of the layers of matrix material being between 0.005 and 5 &mgr;m thick.

Laminated matrix composites

A preferred embodiment of a method for coating a substrate with a chemical compound uses a precursor liquid. This precursor liquid preferably serves as a reagent in the coating process and is housed in a reactor. Once the precursor liquid is placed in the reactor, the substrate is immersed in the precursor liquid. While the substrate is immersed in the precursor liquid, which may or may not contain solid particles, the liquid is fluidized by one or more possible methods: passing a gas through the liquid; recirculating the liquid; and stirring the liquid. In the preferred embodiment, inductive heating of the substrate is performed by an induction coil. The induction coil will be driven by a generator to emit a high frequency alternating current electromagnetic field such that only the substrate is directly heated. Heating the substrate in a fluidized bed will cause chemical vapor deposition or chemical vapor infiltration to occur and the desired chemical compound, or element, to be deposited on the substrate. The compound that coats the substrate may be either the vaporized precursor liquid, a gas injected into the reactor, or some combination of the two.

Fluidized bed coating process with liquid reagent

The fabrication of carbon/carbon composite disks using forced flow-thermal gradient chemical vapor infiltration process using propylene diluted with hydrogen as the reagent is disclosed. The independent variables included concentration of the reagent, total flow rate and preform bottom temperature. The response variables included infiltration time, final porosity, rate of weight gain and deposition rate. The infiltration time and rate of weight gain are affected only by the three independent variables. The densification of the composites is monitored by the back pressure. The composites were cut into slices 1 cm long, 4 mm wide and 2 mm deep to measure the uniformity of densification, which varied very little within a composite. Coating thickness as a function of position increased exponentially from the cold side to the hot side of the composite. The coating thicknesses near the cold side and the hot side are used to calculate the rate constant for the pyrolysis of propylene in the preform. The activation energy is approximately 18.6 Kcal/mol and the rate constant is given by 1n k=8.2--9375.1/T (K)

Fabrication of carbon/carbon composites by forced flow-thermal gradient

A rapid process for the preparation of diamond articles in which a porous, dense preform of diamond particles created by particle packing methods is subjected to forced flow chemical vapor infiltration of a carbon containing reagent gas resulting in the preparation of thick diamond articles.

Rapid process for the preparation of diamond articles

A method for applying a metal film barrier layer between a substrate and a superconductor coating or over a superconductivity coating using chemical vapor deposition in which low vapor pressure reactants are used, is disclosed, which comprises the steps of providing a substrate and a quantity of metal-bearing reagent and one or more reagents, placing the substrate within the furnace, introducing the metal-bearing reagent by a powder feeder means and then the reagents at different times into and reacting them in the furnace, resulting in the deposition first of a coating of metal onto the substrate and then of a coating consisting essentially of the superconducting reactant components onto the metal film; said reagents generally chosen to yield the group of oxide superconductors.

Method for the chemical vapor deposition of group IB and group VIIIB

A method for applying coatings to substrates using chemical vapor deposition with low vapor pressure reagents is disclosed which comprises the steps of: (a) placing a substrate in a furnace means; (b) directly introducing powder reagents by a powder feeder means into said furnace means; and (c) vaporizing and reacting said reagents within said furnace means resulting in the deposition from the vapor phase of a coating on said substrate, wherein said coating can be an oxide superconductor.

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Marietta, GA, United States of America

Walter J Lackey