Dow Corning Corporation

Chandan K Saha

William H Atwell

Gary T Burns

Kyuha Chung

Jeffrey Nicholas Bremmer

Michael John Spaulding

Gregg A Zank

Jonathan Lipowitz

Donald M Bartos

Patrick J Harder

Ronald J Keller

This invention pertains to a method for producing thermally stable multi-layer coatings and the coatings produced therefrom. The multi-layer coating is comprised of a first coating produced from hydrogen silsesquioxane having a thickness of 1.25 to 2.25 &mgr;m and a second coating comprising silicon dioxide having a thickness of at least 100 nm. The method for producing the first coating comprises applying a fillerless hydrogen silsesquioxane resin composition onto a substrate and thereafter heating the hydrogen silsesquioxane resin at a temperature of 150&deg; C. to 500&deg; C. for a sufficient period of time to produce a crack-free coating having a thickness of 1.25 &mgr;m to 2.25 &mgr;m. The second coating is produced by depositing, preferably by PECVD, silicon dioxide over the first coating at a thickness of at least 100 nm.

Thermally stable dielectric coatings

This invention pertains to a method for producing crack-free, insoluble, greater than 1.25 .mu.m thick coatings from hydrogen silsesquioxane resin compositions. The method for producing the coating comprises applying a fillerless hydrogen silsesquioxane resin composition onto a substrate and thereafter heating the hydrogen silsesquioxane resin at a temperature of less than 500.degree. C. for a controlled period of time to produce the crack-free coating having a thickness of greater than 1.25 .mu.m. The resins may be cured in an inert or oxygen containing environment.

Method for producing thick crack-free coatings from hydrogen

Method for producing thick crack-free coating from hydrogen

Disclosed is a process for the formation of silicon carbide powder in which vaporized polysiloxanes are reacted and pyrolyzed in a single heating step to form the silicon carbide powder. The process is simple and inexpensive and yields powder having desirable characteristics.

Process for preparing silicon carbide powder from vaporized polysiloxanes

The preparation of porous ceramic bodies by sintering certain curable organopolysiloxanes filled with silicon carbide powders. This process is advantageous in that the green bodies have relative high strengths and thus can be easily handled and, if desired, machined before sintering.

Porous silicon carbide ceramics using filled polysiloxanes

The preparation of highly densified ceramic bodies by the sintering of certain preceramic polysilazanes filled with silicon carbide powders, metal-containing sintering aids, and, optionally, polysilazane curing agents is described. Such highly densified ceramic bodies can be prepared by either a pressureless sintering process or a hot press sintering process. The compositions of this invention can be formed into desired shapes and then sintered to form ceramic, shaped bodies with high densities. One advantage of the present invention is that the green bodies have relative high strengths and thus can be easily handled and, if desired, machined before sintering. The preceramic polysilazanes useful in this invention must yield ceramic chars which contains free or excess carbon in addition to carbon in the form of silicon carbide upon pyrolysis to elevated temperatures.

Highly densified bodies from preceramic polysilazanes filled with

The preparation of highly densified ceramic bodies by the sintering of certain organopolysiloxanes filled with silicon carbide powders, and metal-containing sintering aids is described. Such highly densified ceramic bodies can be prepared by either a pressureless sintering process or a hot press sintering process. The compositions of this invention can be formed into desired shapes and then sintered to form ceramic, shaped bodies with high densities. One advantage of the present invention is that the green bodies have relative high strengths and thus can be easily handles and, if desired, machined before sintered. The organopolysiloxanes useful in this invention must yield a ceramic char which contains free or excess carbon in addition to carbon in the form of silicon carbide upon pyrolysis to elevated temperatures.

Highly densified bodies from organopolysiloxanes filled with silicon

The preparation of highly densified ceramic bodies by sintering certain curable organopolysiloxanes filled with silicon carbide powders, metal-containing sintering aids, and organopolysiloxane curing agents described. Such highly densified ceramic bodies can be prepared by either a pressure-less or a hot press sintering process. The compositions of this invention can be formed into desired shapes and then sintered to form ceramic, shaped bodies with high densities. One advantage of the present invention is that the green bodies have relative high strengths and thus can be easily handled and, if desired, machined before sintering. The curable organopolysiloxanes useful in this invention must yield a ceramic char which contains free or excess carbon in addition to carbon in the form of silicon carbide upon pyrolysis to elevated temperatures.

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Midland, MI, United States of America

Chandan K Saha