Versar, Inc.

Robert G Shaver

William R Leake

The process of manufacturing shaped structures comprising silicon carbide and carbon, including forming precursors of heat carbonizable synthetic resin material having dispersed therein siliceous material, heating a batch of precursors to a temperature in the range of 2000.degree. F. to 3000.degree. F. while confining them within a graphite boat which substantially surrounds the precursors except for small openings sufficient to circulate gases through the boat, maintaining the heating of the boat and the batch for a time in the range of 4 to 24 hours to carbonize the resin material and promote solid state reactions between the carbon formed from the resin material and the siliceous material, while continuously flushing the boat with inert gases, subsequently removing the heated boat containing the batch and immediately confining it in an unheated chamber in the presence of an inert atmosphere until the boat and batch are cooled below the auto-ignition temperature of carbon in air, and recovering the shaped silicon carbide and carbon structures from the boat. The product of the process forms part of this disclosure and can be further processed to remove uncombined siliceous materials by treating with hydrofluoric acid.

Silicon carbide and carbon structures and method of making

An apparatus for making hollow carbon microspheres starting with hollow microballoons made of a material which can by heating be degraded to a carbon structure having a shape similar to that of the original microballoon. The disclosure teaches specific batch treating steps and apparatus for optimizing the rate of production of the microspheres, while at the same time minimizing degradation, rupture and cracking of the resulting carbon product.

Apparatus for making hollow carbon microspheres

A process and apparatus for making hollow carbon microspheres starting with hollow microballoons made of a material which can by heating be degraded to a carbon structure having a shape similar to that of the original microballoon. The disclosure teaches specific batch treating steps and apparatus for optimizing the rate of production of the microspheres, while at the same time minimizing degradation, rupture and cracking of the resulting carbon product.

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Alexandria, VA, United States of America

Robert G Shaver