Coatings for directional eutectics. Final report. [NiCrAlCy coating for NiTaC-13]

Technical Report · Sun Jul 25 04:00:00 EDT 1976

OSTI ID:7216906

Rairden, J R; Jackson, M R

Significant advances have been made in the development of an environmentally stable coating for a very-high-strength, directionally solidified eutectic alloy designated NiTaC-13. Three duplex (two-layer) coatings survived 3,000 hours on a cyclic oxidation test (1,100 C to 90 C). These coatings were fabricated by first depositing a layer of NiCrAl(Y) by vacuum evaporation from an electron beam heated source, followed by depositing an aluminizing overlayer. The alloy after exposure with these coatings was denuded of carbide fibers at the substrate/coating interface. It was demonstrated that TaC fiber denudation can be greatly retarded by applying a carbon-bearing coating. The coating was applied by thermal spraying followed by aluminization. Specimens coated with NiCrAlCY+Al survived over 2,000 hours in the cyclic oxidation test with essentially no TaC denudation. Coating ductility was studied for coated and heat-treated bars, and stress rupture life at 871 C and 1,100 C was determined for coated and cycled bars.

• Research Organization: General Electric Co., Schenectady, NY (USA). Metallurgy Lab.
• OSTI ID: 7216906
• Report Number(s): N-76-29370; NASA-CR-135050; SRD-76-076
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
ALUMINIUM ALLOYS
CARBON
CARBON COMPOUNDS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
COATINGS
DEPOSITION
ELEMENTS
EUTECTICS
HIGH TEMPERATURE
MEDIUM TEMPERATURE
NICKEL ALLOYS
NONMETALS
OXIDATION
SURFACE COATING
TANTALUM ALLOYS
VACUUM COATING
VERY HIGH TEMPERATURE
YTTRIUM ALLOYS