Overlays coating for superalloys
AssigneeUnited Technologies Corporation
InventorsDinesh K. Gupta, David S. Duvall
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Abstract
Improved coating compositions are described for the protection of superalloys at elevated temperatures. The coatings are of the MCrAlY type where M is nickel or cobalt and are significantly improved by the addition of from 0.1-7% silicon and 0.1-2% hafnium. Coatings of the invention are preferably applied by plasma spraying and as so applied are found to be substantially more effective than prior art coatings.
Claims14
A coating composition suited for the protection of metallic substrates against high temperature oxidation and corrosion consisting essentially of 5-40% Cr, 8-35% Al, 0.1-2.0% of an oxygen active element selected from the Group IIIB elements including the lanthanides and the actinides, and mixtures thereof, 0.1-7.0% Si and 0.1-2.0% Hf balance selected from the group consisting of Ni, Co and mixtures thereof.
A method for improving the high temperature oxidation MCrAlY type protective coatings which comprises adding from 0.1-7.0% Si and 0.1-2.0% Hf to the coating composition wherein M is selected from the group consisting of Ni, Co and mixtures thereof.
A coating composition suited for the protection of metallic substrates against high temperature oxidation and corrosion consisting essentially of 15-25% Cr, 10-20 % Al, 0.1-2.0% of an oxygen active element selected from the Group IIIB elements including the lanthanides and the actinides, and mixtures thereof, 0.1-7.0% Si and 0.1-2.0% Hf balance selected from the group consisting of Ni and Co.
A coating composition suited for the protection of metallic substrates against high temperature oxidation and corrosion consisting essentially of 15-25% Cr, 10-20% Al, 0.1-2.0% of an oxygen active element selected from the Group IIIB elements including the lanthanides, the actinides and mixtures thereof, 0.1-7.0% Si and 0.1-2.0% Hf, 15-25% Co balance essentially nickel.
Dependencies are inferred from the claim text.