Patent ID: 8481117

Claim:
A method for forming thermally grown alpha alumina scale on a substrate, comprising: providing a heating chamber having a heat source and an oxidizing gas source that is selectively operable to provide a stream of oxidizing gas, wherein the heat source includes a heating element and an acceptor plate comprising graphite; providing at least one substrate disposed in the heating chamber, which substrate has a composition sufficient to permit formation of an alpha alumina scale on one or more surfaces; maintaining a vacuum in the heating chamber at a level that inhibits formation of one or more low temperature oxides on the one or more surfaces of the substrate; heating at least one of the one or more surfaces of the substrate, to a predetermined temperature at or above 1800 degrees Fahrenheit, by radiating heat energy from the heating element, through the acceptor plate, to the one or more surfaces of the substrate; and directing the stream of oxidizing gas at a controlled rate through the acceptor plate toward one or more heated surfaces of the substrate.