Abstract:
Ferrous metal articles, such as stainless steel aircraft components, e.g. turbine vanes, vane/shrouds and the like, characterized by at least one brazed joint, in which the braze is a non-ferrous alloy are aluminized by first uniformly plating onto the entire surface of said articles including the braze, a coating of an aluminide-forming metal selected from the group consisting of iron, nickel, cobalt and chromium and then thermally diffusing aluminum over the entire surface of the article, including the braze, such that a sacrificial corrosion resistant coating is produced characterized by the presence of an aluminide compound selected from the group consisting of iron aluminide, nickel aluminide, cobalt aluminide and chromium aluminide. The aluminide coatings are further enhanced by the application of a non-metallic coating, e.g a conversion coating.
Abstract:
Ferrous metal articles, such as stainless steel aircraft components, e.g., turbine vanes, vane/shrouds and the like, characterized by at least one brazed joint, in which the braze is a non-ferrous alloy are aluminized by first uniformly plating onto the entire surface of said articles including the braze, a coating of an aluminide-forming metal selected from the group consisting of iron, nickel, cobalt and chromium and then thermally diffusing aluminum over the entire surface of the article, including the braze, such that a sacrificial corrosion resistant coating is produced characterized by the presence of an aluminide compound selected from the group consisting of iron aluminide, nickel aluminide, cobalt aluminide and chromium aluminide. The aluminide coatings are further enhanced by the application of a non-metallic coating, e.g. a conversion coating.
Abstract:
A method is provided for improving the corrosion resistance of material substrates. The method is particularly applicable to the protection of metal substrates, such as ferrous metal articles, among other metals, and, in particular, to the protection of low alloy steel gas turbine engine components for aircraft in which the surface is provided with an adherent protective layer of a sacrificial coating rich in magnesium and also containing silicon, oxygen and optionally iron. The coating is characterized by the presence of magnesium silicide as a major active constituent.