Method for producing metallic articles having durable ceramic thermal barrier coatings
AssigneeUnited Technologies Corporation
InventorsNicholas E. Ulion, Duane L. Ruckle
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Abstract
A coated article and method for producing the coated article are described. The article is coated with a system which provides protection against oxidation and corrosion and which significantly reduces the substrate temperature. An MCrAlY layer is applied to the article to be protected and a columnar grain ceramic is applied by vapor deposition to the MCrAlY coated article. An alumina layer which exists between the MCrAlY layer and the columnar ceramic layer provides for the adherence of the columnar layer to the MCrAlY layer. An important feature of the invention is that the interface between the MCrAlY layer and the alumina layer has a low surface roughness and this greatly improves the columnar ceramic layer adherence.
Claims12
A method for producing a metallic article having a durable ceramic thermal barrier coating said method consisting essentially of:
- a. providing a superalloy substrate with a clean surface
- b. applying a thin adherent layer of MCrAlY to the clean surface
- c. polishing the MCrAlY layer to a smoothness of less than about 25 microinches RMS
- d. applying a columnar ceramic coating to the polished MCrAlY layer by vapor deposition
- e. heat treating the columnar ceramic coated article in a oxygen containing atmosphere to develop an alumina layer between the MCrAlY and the columnar ceramic coating.
Dependencies are inferred from the claim text.