Method for preventing the formation of secondary reaction zone in susceptible articles, and articles prepared by the method

A method for preparing a coated nickel-base superalloy article that is otherwise susceptible to the formation of a secondary reaction zone, the method comprising the steps of

• furnishing a nickel-base superalloy article substrate having thereon an initial aluminum-containing coating comprising an initial-coating additive zone and an initial-coating diffusion zone that are substantially free of platinum and palladium, the article being susceptible to the formation of the secondary reaction zone if heated to an elevated SRZ reaction temperature for an SRZ reaction period of time;
• thereafter
• removing the initial-coating additive zone and the initial-coating diffusion zone;
• and thereafter
• depositing a subsequent aluminum-containing coating onto the article substrate, the subsequent aluminum-containing coating including a subsequent-coating additive zone and a subsequent-coating diffusion zone that are substantially free of platinum and palladium, the article substrate with the subsequent aluminum-containing coating being otherwise susceptible to the formation of the secondary reaction zone if heated to the elevated SRZ reaction temperature for the SRZ reaction period of time.

A method for preparing a coated nickel-base superalloy article that is otherwise susceptible to the formation of a secondary reaction zone, the method comprising the steps of

• furnishing a nickel-base superalloy article substrate that is susceptible to the formation of the secondary reaction zone if coated with an aluminum-containing layer and heated to an elevated SRZ reaction temperature for an SRZ reaction period of time;
• thereafter
• conditioning the nickel-base superalloy article substrate to be resistant to the formation of secondary reaction zone, the step of conditioning including the step of
• depositing a conditioning material onto a surface of the article substrate, and thereafter
• removing the conditioning material from the article substrate;
• and thereafter
• depositing a subsequent aluminum-containing coating onto the article substrate, the subsequent aluminum-containing coating including a subsequent-coating additive zone and a subsequent-coating diffusion zone, the article substrate with the subsequent aluminum-containing coating being otherwise susceptible to the formation of the secondary reaction zone if heated to the elevated SRZ reaction temperature for the SRZ reaction period of time.