Abstract: 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.

Abstract: 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.

Abstract: A chemical vapor deposition (CVD) process for preparing fiber-reinforced ceramic composites. A specially designed apparatus provides a steep thermal gradient across the thickness of a fibrous preform. A flow of gaseous ceramic matrix material is directed into the fibrous preform at the cold surface. The deposition of the matrix occurs progressively from the hot surface of the fibrous preform toward the cold surface. Such deposition prevents the surface of the fibrous preform from becoming plugged. As a result thereof, the flow of reactant matrix gases into the uninfiltrated (undeposited) portion of the fibrous preform occurs throughout the deposition process. The progressive and continuous deposition of ceramic matrix within the fibrous preform provides for a significant reduction in process time over known chemical vapor deposition processes.

Abstract: This invention relates to a method for determining defective final layers of carbon on triso-coated fuel particles and the like. Samples of the particles are subjected to a high temperature treatment with gaseous chlorine and thereafter radiographed. The chlorine penetrates through any defective carbon layer and reacts with the underlying silicon carbide resulting in the volatilization of the silicon as SiCl.sub.4 leaving carbon as a porous layer. This porous carbon layer is easily detected by the radiography.

Abstract: Carbon-coated microspheroids useful as fuels in nuclear reactors are produced with a low percentage of cracked coatings and are imparted increased strength and mechanical stability characteristics by annealing immediately after the carbon coating processes.