Thermal barrier coating for metallic components
AssigneeCaterpillar Inc.
InventorJohn A. Grassi
Life of this patent
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Abstract
A coating for a metallic substrate has a metallic bond coat, a metallic seal coat and a centrally disposed layer of ceramic material. Transition layers comprising a controllably positioned mixture of metallic and ceramic materials are interposed, respectively, between the bond coat and the central layer of ceramic material, and between the seal coat and the central layer of ceramic material. The coating provides a desirable thermal barrier for internal engine components. Further, the coating is graded to avoid harmful internal thermal stress between dissimilar materials in the coating, and has a sealed external surface that is resistant to corrosion, erosion, hot gas infiltration, and wear during operation in an internal combustion engine.
Claims22
A coating for a metallic substrate, comprising:
- a metallic bond coat having a coefficient of thermal expansion substantially equal to that of said metallic substrate and being bonded to said metallic substrate;
- a first transition layer having a first surface, a second surface spaced from said first surface, and a composition comprising a mixture of a metallic material and a ceramic material, said first surface being bonded to said metallic bond coat, and said mixture of said metallic and ceramic materials being controllably positioned within said first transition layer with the composition of said first transition layer at said first surface being at least about 50% the metallic material and the composition of said first transition layer at said second surface being at least about 50% the ceramic material;
- a centric layer having a first surface and a second surface spaced from said first surface, said first surface of the centric layer being bonded to the second surface of said first transition layer, and said centric layer having a composition consisting essentially of a low-thermally conductive ceramic material;
- a second transition layer having a first surface, a second surface spaced from said first surface, and a composition comprising a mixture of a metallic material and a ceramic material, said first surface being bonded to said second surface of the centric layer, and said mixture of the metallic and ceramic materials being controllably positioned within said second transition layer with the composition of said second transition layer at said first surface being at least about 50% the ceramic material and the composition of said second transition layer at said second surface being at least about 50% the metallic material;
- and,
- a metallic seal coat having a first surface bonded to the second surface of said second transition layer and a porosity not greater than about 5%.
Dependencies are inferred from the claim text.