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US 12,545,791 B2Granted
Chromate-free and phosphate-free ceramic coating compositions for hot corrosion protection of substrates
AssigneePraxair S.T. Technology, Inc.
InventorsZhihong Tang, Daryl G. Copeland, Mark W. Perpall
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Abstract
Novel multilayer aqueous slurries and coatings for hot corrosion protection of substrates are provided that exhibit improved resistance to type II hot corrosion while also being hexavalent chromium free. The compositions represent a notable departure and performance improvement from conventional coating systems utilized for hot corrosion protection.
Claims14
An aqueous slurry composition for the production of a multilayer coating system for hot corrosion protection of a substrate comprising:
- a basecoat slurry, comprising:
- a first binder comprising a first silicate-based aqueous solution, wherein said first binder is substantially free of chromate, phosphate, sodium, and potassium;
- and
- metal oxide particles incorporated into said first binder, said metal oxide particles comprising at least one of alumina, chromia, zirconia, zirconia-containing complex oxides, ceria and rare earth oxides;
- metallic particles incorporated into said first binder, said metallic particles comprising MCr or MCrAlY, where Mis Ni or Co, or a combination of Ni and Co;
- a topcoat slurry, comprising:
- a second binder comprising a second silicate-based aqueous solution, wherein said second binder is substantially free of chromate, phosphate, sodium, and potassium, and further wherein the second silicate-based aqueous solution is devoid of the metal oxide particles and the metallic particles.
4 more elements
A multilayer coating system for hot corrosion protection of a substrate, comprising:
- a substrate;
- a basecoat, said basecoat comprising:
- a first ceramic matrix characterized as comprising a first silicate-based matrix, wherein said first silicate-based matrix is substantially free of chromate, phosphate, sodium, and potassium;
- metal oxide particles incorporated into said first ceramic matrix, said metal oxide particles comprising at least one of alumina, chromia, zirconia, zirconia-containing complex oxides, ceria and rare earth oxides;
- metallic particles incorporated into said first ceramic matrix, said metallic particles comprising MCr or MCrAlY, where Mis Ni or Co, or a combination of Ni and Co;
- a topcoat, said topcoat comprising:
- a second ceramic matrix characterized as comprising a second silicate-based matrix, wherein said second silicate-based matrix is substantially free of chromate, phosphate, sodium, and potassium, and further wherein the second silicate-based matrix is devoid of the metal oxide particles and the metallic particles.
4 more elements
Dependencies are inferred from the claim text.