Thermal barrier coating method
AssigneeHowmet Research Corporation
InventorsBruce M. Warnes, Joel Lee Cockerill, John Edward Schilbe
Life of this patent
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Abstract
An outwardly grown diffusion aluminide bondcoat is formed on a superalloy substrate and has higher concentrations of Al and Pt and lower concentrations of harmful impurities (e.g. Mo, W, Cr, Ta, S, etc.) at an outermost region of the bondcoat than at an innermost region thereof adjacent the substrate. The bondcoat is pretreated prior to deposition of a ceramic thermal insulative layer in a manner that reduces grain boundary ridges on the outermost bondcoat surface without adversely affecting the outermost region thereof, and then is heat treated to thermally grow a stable alpha alumina layer on the bondcoat prior to deposition of a ceramic layer.
Claims14
In a method of forming a thermal barrier coating system on a substrate, the steps comprising:
- forming on said substrate a diffusion aluminide bondcoat that has a higher concentration of Al and a lower concentration of a refractory metal at an outermost region of the bondcoat than at an innermost region thereof that is adjacent said substrate, and
- repetitively moving the bondcoated substrate and abrasive particle media in contact in a container to reduce grain boundary ridges on said bondcoat while leaving at least a portion of said outermost region of said bondcoat.
A method of forming a thermal barrier coating system on a substrate, comprising
- forming on a said substrate a diffusion aluminide bondcoat that has a higher concentration of Al and a lower concentration of a refractory metal at an outermost region of the bondcoat than at an innermost region thereof, and
- heating the bondcoat in air at a temperature of at least 1900 degrees F. for sufficient time to form an alpha phase alumina layer on the bondcoat, and
- depositing a ceramic layer on the alpha alumina layer.
In a method of forming a thermal barrier coating system on a substrate, the steps comprising:
- forming on said substrate a diffusion aluminide bondcoat that has a higher concentration of Al and a lower concentration of a refractory metal at an outermost region of the bondcoat than at an innermost region thereof that is adjacent said substrate, and
- abrading said bondcoat by repetitively moving the bondcoated substrate and abrasive particle media in contact in a container for a time to reduce grain boundary ridges on said bondcoat without removing said outermost region of said bondcoat.
Dependencies are inferred from the claim text.