Disclosed is a process for producing a high-temperature protective coating for metallic components, in particular components of turbomachines which are subjected to thermal loading. The process comprises producing a slip from MCrAlY powder, in which M is at least one metal, and from a Cr powder, applying the slip to the component to be coated and subsequently alitizing the component provided with the slip.

Disclosed is a process for producing a high-temperature protective coating for metallic components, in particular components of turbomachines which are subjected to thermal loading. The process comprises producing a slip from MCrAlY powder, in which M is at least one metal, and from a Cr powder, applying the slip to the component to be coated and subsequently alitizing the component provided with the slip.

Methods for deposition of an aluminide coating on an alloy component positioned within a coating compartment of a retort chamber are provided. According to the method, the coating compartment is purged with an inert gas via a first gas line; a positive pressure is created within the coating compartment utilizing the inert gas; the coating compartment is heated to a deposition temperature; and at least one reactant gas is introduced into the coating compartment while at the positive pressure and the deposition temperature to form an aluminide coating on a surface of the alloy component. Retort coating apparatus are also provided.

Methods for deposition of an aluminide coating on an alloy component positioned within a coating compartment of a retort chamber are provided. According to the method, the coating compartment is purged with an inert gas via a first gas line; a positive pressure is created within the coating compartment utilizing the inert gas; the coating compartment is heated to a deposition temperature; and at least one reactant gas is introduced into the coating compartment while at the positive pressure and the deposition temperature to form an aluminide coating on a surface of the alloy component. Retort coating apparatus are also provided.

A clutch includes: a rotor that has a steel material as a base material and is rotated upon receiving a rotational drive force from a drive source; and an armature that has a steel material as a base material and receives the rotational drive force from the rotor when the armature is attracted to the rotor by a magnetic force. The armature has a contact surface side region that includes a contact surface, which contacts a counterpart when the armature is attracted to the rotor. The contact surface side region has a plurality of pores opened at the contact surface and forms a nitride compound of an element of the base material through nitridization of a part of the base material while the contact surface side region is harder than an unreacted portion of the base material that is not reacted at the nitridization.

A gas turbine component for use in a gas turbine engine includes a substrate a ceramic-based thermal barrier coating (TBC), and a diffusion chromide bond coat between the base material and the TBC. A thermally grown oxide (TGO) layer can be formed on the bond coat prior to application of the TBC. The TBC and the TGO include a common metal oxide. The oxide can be sacrificially in use and soluble in a molten sulfate salt, make the coating system particularly suitable for use in a marine environment.

A nickel-based superalloy part includes a nickel-based superalloy substrate, and a metal sublayer covering the substrate, wherein the metal sublayer includes a first and a second layer, the first layer being located between the substrate and the second layer, the first layer including a first -Ni.sub.3Al phase and a second -Ni phase, the second layer including a first -Ni.sub.3Al phase, a second -Ni phase and a third -NiAl phase, the average atomic fraction of aluminum in the second layer being strictly greater than the average atomic fraction of aluminum in the first layer.

A nickel-based superalloy part includes a nickel-based superalloy substrate, and a metal sublayer covering the substrate, wherein the metal sublayer includes a first and a second layer, the first layer being located between the substrate and the second layer, the first layer including a first -Ni.sub.3Al phase and a second -Ni phase, the second layer including a first -Ni.sub.3Al phase, a second -Ni phase and a third -NiAl phase, the average atomic fraction of aluminum in the second layer being strictly greater than the average atomic fraction of aluminum in the first layer.

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.