Elevated temperature oxidation protection coatings for titanium alloys and methods of preparing the same
AssigneeHoneywell International Inc.
InventorsDerek Raybould, Paul Chipko, William E. Fischer
Life of this patent
Estimating the term…
Abstract
Oxidation protection of a titanium-based alloy is provided with improved fatigue properties by a titanium aluminide coating of between 2 to 12 microns by diffusing the Al into the Ti at a temperature below the melting point of the Al. The coating is gas deposited and protects the titanium-based alloys from oxidation at high temperature utilization.
Claims25
A method of coating a titanium based surface to provide oxidation protection and improved fatigue properties at elevated temperatures, comprising:
- applying a protective coating to the surface, the coating being applied to the surface and having an aluminum conversion layer applied at a temperature below which aluminum does not appreciably react with titanium and of a thickness of less than about 12 microns;
- and
- heat treating the conversion layer so that the aluminum oxidizes and interacts with the titanium to form titanium aluminide.
A method of applying a coating to a titanium-based substrate, comprising:
- applying an aluminum conversion layer of between 2 to 12 microns on the substrate by gaseous deposition, the layer being deposited at a temperature below which aluminum does not appreciably react with titanium;
- and
- heat-treating the conversion layer so that the aluminum oxidizes to form alumina and interacts with the titanium to form the titanium aluminide.
A method of applying a coating to a titanium-based substrate, comprising:
- applying an aluminum conversion layer of between 2 to 12 microns on the substrate by gaseous deposition, the layer being deposited at a temperature below which aluminum does not appreciably react with titanium and below the melting point of Al;
- and
- heat-treating the conversion layer so that the aluminum oxidizes to form alumina and interacts with the titanium to form the titanium aluminide, and the conversion layer is oxidized to form an alumina surface layer.
A method of coating a titanium based surface to provide oxidation protection at elevated temperatures, comprising:
- applying a protective coating to the surface, the coating being applied by applying an aluminum conversion layer to the surface at a temperature below which aluminum does not appreciably react with titanium and of a thickness of less than 12 microns;
- heat treating the conversion layer so that the aluminum oxidizes and interacts with the titanium to form titanium aluminide;
- and
- cleaning the titanium-based alloy surface prior to applying a protective coating.
An oxidation protective coating for a titanium-based alloy surface comprising:
- a heat-treated aluminum conversion layer applied to the titanium-based alloy surface having a thickness of less than 12 microns.
A method of applying a coating to a brazed substrate comprising:
- applying an aluminum conversion layer of between 2 to 12 microns on the substrate by gaseous deposition, the layer being deposited at a temperature below which aluminum does not appreciably react with any titanium which may or may not be present in the braze;
- and
- heat treating the conversion layer so that the aluminum oxidizes to form alumina, and if the braze contains Ti, interacts with the titanium to form titanium aluminide.
Dependencies are inferred from the claim text.