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Abstract

This invention relates to an improved pack mixture composition useful for the formation of a SiC pack cementation coating for protecting a carbonaceous substrate from degradation at temperatures above about 800.degree. F. comprising: Si from about 15% to about 50% by weight of the total composition; B up to about 25% by weight of the total composition when present; SiO.sub.2 from about 0.01% to about 3% by weight of the total composition; and SiC from about 40% to about 85% by weight of the total composition. The invention also relates to a method for protecting a carbonaceous substrate from degradation at temperatures above about 800.degree. F. comprising: preparing a pack mixture composition of from about 15% to about 50% Si, up to about 25% B, from about 0.01% to about 3% SiO.sub.2 and from about 40% to about 85% SiC, all by weight of the total pack mixture composition; coating the carbonaceous substrate with release agent; surrounding the release agent-coated carbonaceous substrate with the pack mixture composition; and firing the carbonaceous substrate for a period of time sufficient to effectuate the formation of a protective SiC pack cementation coating on the carbonaceous substrate. The invention further relates to a cork release agent composition for providing the clean release of spent pack composition from a carbonaceous substrate.

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First Claim