Preparation of a nickle-based superalloy article containing a reactive element and having a decarburized surface and coating

A method for preparing a surface-protected nickel-base superalloy article, comprising the steps of

• providing an article substrate having a surface and having a nominal bulk composition comprising the nickel-base superalloy, the nickel-base superalloy comprising
• more nickel than any other element,
• a reactive element selected from the group consisting of hafnium, zirconium, yttrium, lanthanum, and cerium, and combinations thereof, and
• a nominal bulk composition of carbon;
• and
• depositing a protective layer overlying the surface of the article substrate, the step of depositing a protective layer including steps of
• decarburizing locations where the carbon serves as a barrier to the diffusion of the reactive element from the substrate into the protective layer, and
• depositing an aluminum-containing protective layer overlying the substrate, wherein the step of decarburizing includes the steps of
• depositing a platinum-containing layer overlying the substrate, thereafter
• decarburizing the platinum-containing layer, and thereafter
• depositing the aluminum-containing protective layer overlying the platinum containing layer.

A method for preparing a surface-protected nickel-base superalloy article, comprising the steps of

• providing an article substrate having a surface and having a nominal bulk composition comprising the nickel-base superalloy, the nickel-base superalloy comprising
• more nickel than any other element,
• a reactive element selected from the group consisting of hafnium, zirconium, yttrium, lanthanum, and cerium, and combinations thereof, and
• a nominal bulk composition of carbon;
• and depositing a protective layer overlying the surface of the article substrate, the step of depositing a protective layer including steps of
• depositing a platinum-containing layer overlying the substrate, thereafter
• decarburizing the platinum-containing layer, and thereafter
• depositing an aluminum-containing protective layer overlying the platinum-containing layer.

A method for preparing a surface-protected nickel-base superalloy article, comprising the steps of

• providing an article substrate having a surface and having a nominal bulk composition comprising the nickel-base superalloy, the nickel-base superalloy comprising
• more nickel than any other element,
• a reactive element selected from the group consisting of hafnium, zirconium, yttrium, lanthanum, and cerium, and combinations thereof, and
• a nominal bulk composition of carbon;
• and
• depositing a protective layer overlying the surface of the article substrate, the step of depositing a protective layer including steps of
• depositing an aluminum-containing protective layer overlying the surface of the article substrate, and thereafter
• decarburizing the substrate with the aluminum-containing protective layer deposited thereon, the step of decarburizing the substrate being performed in a reducing atmosphere.