Abstract: A thermal barrier coating for high temperature applications has improved resistance to heat flow. The coating comprises a large number of these (nanometer scale) layers separated by interfaces which are effective in retarding heat flow. The coating material will typically be oxide based ceramics and the coating has particular applications in gas turbine engines.

Abstract: A class of protected coatings for superalloys is described in which the coatings compositions are based on the compositions of the underlying substrate. By tailoring the coatings to the substrate composition, diffusional stability results and the other mechanical properties of the coating such as coefficient of thermal expansion and modulus, are similar to that of the substrate. The coating contains 7.5-11% Al, 9-16% Cr, 0.1-0.5% Hf, 2-8% Ta, 0.01-0.8% Y, balance Ni along with other elements all chosen to be similar in type and quantity to the substrate composition.

Abstract: A coated article and method for producing the coated article are described. The article is provided with a coating system which provides protection against hot corrosion at moderate temperatures (1200-1700.degree. F.). An overlay coating based on a metal selected from the group consisting of iron, nickel or cobalt or mixtures thereof and containing chromium and optionally aluminum, yttrium and/or hafnium is applied to the article to be protected. A silicon rich surface zone is produced at the surface of the overlay coating. Methods including pack cementation and physical vapor deposition are described for producing the coating.

Abstract: A coated article and method for producing the coated article are described. The article is provided with a coating system which provides protection against hot corrosion at moderate temperatures (1200.degree.-1700.degree. F.). An overlay coating based on a metal selected from the group consisting of iron, nickel or cobalt or mixtures thereof and containing chromium and optionally aluminum, yttrium and/or hafnium is applied to the article to be protected. A silicon rich surface zone is produced at the surface of the overlay coating. Methods including pack cementation and physical vapor deposition are described for producing the coating.