Thermal barrier coating having a thin, high strength bond coat
AssigneeHoneywell International Inc.
InventorsThomas E. Strangman, Derek Raybould
Life of this patent
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Abstract
A thermal barrier coating for nickel based superalloy articles such as turbine engine vanes and blades that are exposed to high temperature gas is disclosed. The coating includes a columnar grained ceramic layer applied to a platinum modified Ni3Al gamma prime phase bond coat having a high purity alumina scale. The preferred composition of the bond coat is 5 to 16% by weight of aluminum, 5 to 25% by weight of platinum with the balance, at least 50% by weight, nickel. A method for making the bond coat is also disclosed.
Claims26
A method of applying a thermal barrier coating to a nickel based superalloy substrate comprising the steps of:
- a) applying a layer of platinum to a surface of said substrate;
- b) applying a layer of aluminum onto said platinum layer;
- c) growing an aluminum oxide scale layer from said aluminum layer;
- d) converting said aluminum oxide scale layer to a crystallographically stable alpha phase during heat treatment that diffuses nickel from said substrate to form a platinum modified Ni3Al gamma prime phase bond coat;
- and
- e) applying a ceramic coat over said bond coat.
A method of applying a thermal barrier coating to a nickel based superalloy substrate, comprising:
- a) applying a layer of platinum having a maximum thickness of 1.2 microns as applied to a surface of said substrate;
- b) applying a layer of aluminum onto said platinum layer;
- c) growing an aluminum oxide scale layer from said aluminum layer;
- d) converting said aluminum oxide scale layer to a crystallographically stable alpha phase during heat treatment that diffuses nickel from said substrate to form a platinum modified Ni3Al gamma prime phase bond coat;
- and
- e) applying a ceramic coat over said bond coat.
A method of applying a thermal barrier coating to a nickel based superalloy substrate, comprising:
- a) applying a layer of platinum to a surface of said substrate;
- b) applying a layer of aluminum onto said platinum layer;
- c) heat treating said coating to grow a continuous aluminum oxide scale having a metastable non-alpha crystal structure from said aluminum layer;
- d) diffusing said platinum and aluminum into said substrate to form a platinum modified Ni3Al gamma prime phase bond coat that has a crystallographic texture of said substrate;
- e) heat treating said substrate to convert the said metastable aluminum oxide scale to a crystallographically stable alpha phase;
- and
- f) applying a ceramic coat over said bond coat.
Dependencies are inferred from the claim text.