United Technologies Corporation

Keith Douglas Sheffler

Gary M Lomasney

Stephen Douglas Murray

John J Marcin

Raymond W Vine

Donald G Nordstrom

Charles E Bevan

Yan Chai

Thomas J Radzavich

A method is disclosed for providing a TBC system including grooves or other features between the bond coat/substrate and the ceramic thermally insulating layer. The features are initially provided by selectively removing material to define the features, for example by laser. Any disturbed surface layer, e.g., re-cast material in the case of a laser or plastically worked material in the case of machining, is then chemically removed, leaving the remaining material with a microstructure of a more uniform geometry, and free of disturbed material. The ceramic layer is then applied. TBC systems using the method show improved durability, with lives up to 4&times; longer than prior TBC systems.

Thermal barrier coating having improved durability and method of providing the coating

The invention is a process for removing ceramic thermal barrier layers from gas turbine engine hardware. A combination of chemical and mechanical steps are used to remove the thermal barrier coating from the substrate without removing the bond coat from the substrate. The process leaves the bond coat on the substrate in condition to receive a repair ceramic thermal barrier coating. The process includes a caustic solution treatment in an autoclave under controlled conditions followed by a mechanical abrasion process.

Thermal barrier removal process

A thermal barrier coating system for the protection of nickel and cobalt base superalloys at elevated temperature comprises 7% yttria partially stabilized zirconia plasma sprayed in air on a plasma sprayed NiCoCrAlY bond coat which has been plasma sprayed in air.

Thermal barrier coating system

This invention relates to the application of plasma sprayed coatings to the surface of components which have small holes therein, such as hollow, air cooled blades or vanes used in turbine engines. Coating material is prevented from depositing on the wall surface of the holes by the presence of fugitive plugs in the holes during the coating process. The plugs are removed after the coating has been applied, resulting in the holes being open and unobstructed.

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Wethersfield, CT, United States of America

Keith Douglas Sheffler