A process for applying a chromized layer on a substrate by first applying an overlay coating to a portion of the substrate, and subsequently contacting a different portion of the substrate and the overlay with a gas containing gaseous chromium, wherein the gaseous chromium can be generated from a chromium source and an activator. The process prepares the substrate, often a jet engine airfoil, for service.

A method for treating a coated article having a depleted layer following exposure of the coated article to an operational temperature is disclosed. The method includes applying an aluminizing composition to the article, forming an overlay aluminide coating on the article from the aluminizing composition, heat treating the overlay aluminide coating, and diffusing aluminum from the overlay aluminide coating into the depleted layer, transforming at least a portion of the depleted layer into a rejuvenated layer. The depleted layer includes a depleted concentration of aluminum relative to a corresponding layer of the coated article prior to the coated article being exposed to the operational temperature. The rejuvenated layer includes a rejuvenated concentration of aluminum which is elevated relative to the depleted concentration of aluminum. A treated article includes a substrate, a rejuvenated aluminide layer disposed on the substrate, and an overlay aluminide coating disposed on the rejuvenated aluminide layer.

A method for vapor phase deposition of a metal coating onto parts made of superalloys, which includes arranging the parts in a chamber in a presence of grains of a donor of the coating metal and an activator capable of together forming a halide of the coating metal, and heating the chamber under an inert gas or reducing gas atmosphere to a temperature at which the coating metal halide reacts with the alloy of the parts. A bed of the grains is arranged on the bottom of at least one box, then a mounting for the parts is placed on the bed of grains, the mounting including support columns that keep the parts separate from the bed of grains, and the gas is injected into the box, when the box is closed, via a side located above the bed of grains.

A method for vapor phase deposition of a metal coating onto parts made of superalloys, which includes arranging the parts in a chamber in a presence of grains of a donor of the coating metal and an activator capable of together forming a halide of the coating metal, and heating the chamber under an inert gas or reducing gas atmosphere to a temperature at which the coating metal halide reacts with the alloy of the parts. A bed of the grains is arranged on the bottom of at least one box, then a mounting for the parts is placed on the bed of grains, the mounting including support columns that keep the parts separate from the bed of grains, and the gas is injected into the box, when the box is closed, via a side located above the bed of grains.

A method for locally treating a plate is disclosed. A pattern formed from a compound containing at least one alloying element is applied onto at least one surface of the plate. At least the surface of a contacting layer including the pattern is covered by adequately heat-resistant material. The plate is subsequently heat treated in order to diffuse the alloying element into the plate.

A method for locally treating a plate is disclosed. A pattern formed from a compound containing at least one alloying element is applied onto at least one surface of the plate. At least the surface of a contacting layer including the pattern is covered by adequately heat-resistant material. The plate is subsequently heat treated in order to diffuse the alloying element into the plate.

A method for coating a metallic substrate includes applying an MCrAlY coating. Machining removes the MCrAlY coating from one or more regions of the substrate. A simultaneous aluminizing and chromizing: aluminizes an interior surface region of the substrate lacking the MCrAlY and at least a portion of a region where the MCrAlY remains; and chromizes an exterior surface region of the substrate lacking the MCrAlY and at least a different portion of the region where the first MCrAlY remains.

A method for coating a metallic substrate includes applying an MCrAlY coating. Machining removes the MCrAlY coating from one or more regions of the substrate. A simultaneous aluminizing and chromizing: aluminizes an interior surface region of the substrate lacking the MCrAlY and at least a portion of a region where the MCrAlY remains; and chromizes an exterior surface region of the substrate lacking the MCrAlY and at least a different portion of the region where the first MCrAlY remains.

Unique and improved chromizing processes are disclosed. The processes involve forming localized chromizing coatings onto selected regions of a substrate. The chromium diffusion coatings are locally applied to selected regions of substrates in a controlled manner, in comparison to conventional chromizing processes, and further in a manner that produces less material waste and does not require diffusion-stop-off masking. Prior to or after a localized slurry chromizing process of the present invention, a layer of a platinum-group-metal (PGM) is applied to produce a PGM-modified chromium diffusion coating onto selected regions of a substrate. A second coating can be selectively applied onto other regions of the substrate.

Unique and improved chromizing processes are disclosed. The processes involve forming localized chromizing coatings onto selected regions of a substrate. The chromium diffusion coatings are locally applied to selected regions of substrates in a controlled manner, in comparison to conventional chromizing processes, and further in a manner that produces less material waste and does not require diffusion-stop-off masking. Prior to or after a localized slurry chromizing process of the present invention, a layer of a platinum-group-metal (PGM) is applied to produce a PGM-modified chromium diffusion coating onto selected regions of a substrate. A second coating can be selectively applied onto other regions of the substrate.