Gte Laboratories Incorporated

Hague International

Robert A Penty

Sergej-Tomislav V Buljan

Vinod K Sarin

John W Bjerklie

Paul G LaHaye

Paul G Lallaye

A composite article and cutting tool are prepared by densification to form a body consisting essentially of particles of hard refractory material uniformly distributed in a matrix consisting essentially of a first phase and a second phase, said first phase consisting essentially of crystalline silicon nitride and said second phase being an intergranular refractory phase comprising silicon nitride and a suitable densification aid selected from the group consisting of yttrium oxide, zirconium oxide, hafnium oxide and the lanthanade rare earth oxides and mixture thereof.

Method of machining cast iron

The heat exchange tube has a porous thermal shock resistant outer shell composed of a corrosion resistant ceramic material that may have a finned outer surface or a plain cylindrical outer surface. The outer shell contains an inner tube composed of a dense nonporous ceramic which is capable of containing high pressure gases, but which may not be as thermally shock resistant or corrosion resistant as the outer shell. The inner tube is formed of a dense ceramic material such as a highly dense silicon carbide or silicon nitride having at each end a like density insert. The end inserts provide sealing surfaces to contact other components in the heat exchanger such as identical ceramic tube assemblies to form a gas-type pressure seal. The inner tube can be fabricated by a deposition technique suh as a chemical or physical vapor deposition, and alternatively, can be made separately and press fitted into the outer shell or the outer shell can be cast or otherwise formed around the inner tube. As an alternative solution, the dense inner tube and end seals can be integrated into a single component performing the functions of all three components, i.e., the two end seals and the inner tube.

Composite ceramic heat exchange tube

Abrasion resistant silicon nitride based articles

The heat exchange tube has a porous thermal shock resistant outer shell composed of a corrosion resistant ceramic material that may have a finned outer surface or a plain cylindrical outer surface. The outer shell contains an inner tube composed of a dense nonporous ceramic which is capable of containing high pressure gases, but which may not be as thermally shock resistant or corrosion resistant as the outer shell. The inner tube is formed of a dense ceramic material such as a highly dense silicon carbide or silicon nitride having at each end a like density insert. The end inserts provide sealing surfaces to contact other components in the heat exchanger such as identical ceramic tube assemblies to form a gas-type pressure seal. The inner tube can be fabricated by a deposition technique such as a chemical or physical vapor deposition, and alternatively, can be made separately and press fitted into the outer shell or the outer shell can be cast or otherwise formed around the inner tube. As an alternative solution, the dense inner tube and end seals can be integrated into a single component performing the functions of all three components, i.e., the two end seals and the inner tube.

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Cape Elizabeth, ME, United States of America

Robert A Penty