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The United States of America As Represented by the United States

Sandia Corporation

Monte Carl Nichols

David R Wheeler

Douglas A Loy

LeRoy L Whinnery

John H Kinney

LeRoy Louis Whinnery

Rudolph Nusshardt

Ulrich K Bonse

Warren N Massey

Quintin C Johnson

Ralph A Saroyan

The present invention is based, in part, on a method for combining a mixture of hydroxide and hydride functional siloxanes to form a polysiloxane polymer foam, that leaves no residue (zero char yield) upon thermal decomposition, with ceramic and/or metal powders and appropriate catalysts to produce porous foam structures having compositions, densities, porosities and structures not previously attainable. The siloxanes are mixed with the ceramic and/or metal powder, wherein the powder has a particle size of about 400 .mu.m or less, a catalyst is added causing the siloxanes to foam and crosslink, thereby forming a polysiloxane polymer foam having the metal or ceramic powder dispersed therein. The polymer foam is heated to thermally decompose the polymer foam and sinter the powder particles together. Because the system is completely nonaqueous, this method further provides for incorporating reactive metals such as magnesium and aluminum, which can be further processed, into the foam structure.

Method for forming porous sintered bodies with controlled pore structure

A method of preparing near net shape, monolithic, porous SiC foams is disclosed. Organosilicon precursors are used to produce polymeric gels by thermally induced phase separation, wherein, a sufficiently concentrated solution of an organosilicon polymer is cooled below its solidification temperature to form a gel. Following solvent removal from the gel, the polymer foam is pretreated in an oxygen plasma in order to raise its glass transition temperature. The pretreated foam is then pyrolized in an inert atmosphere to form a SiC foam.

Process for preparing silicon carbide foam

A computerized three-dimensional x-ray tomographic microscopy system is disclosed, comprising:

X-ray tomographic image magnification process, system and apparatus

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Livermore, CA, United States of America

Monte Carl Nichols