Endurance of NiA1 coatings by controlling thermal spray processing variables

A method for applying a thermal barrier coating system having a substantially stoichiometric NiAl bond coat that includes Cr to a superalloy turbine component to achieve an improved furnace cycle test (FCT) Life, comprising the steps of:

• providing a superalloy turbine component comprised of a material selected from the group consisting of a nickel-based superalloy and a cobalt-based superalloy;
• providing a powder having a size in the range of about 10 microns to about 37 microns of substantially stoichiometric NiAl, sufficient Cr up to a maximum of about 10 atomic percent to promote the formation of at least surface α-alumina on the NiAl, and additions of up to 1.2 atomic percent of at least one element selected from the group consisting of Ce, Pr, Nd, Pm Sm and Zr, and combinations thereof;
• applying the powder to a substrate of the component to provide a coating of from about 0.003″ to about 0.004″ thick with a HVOF process using hydrogen as a fuel having a reducing flame;
• mechanically working the coating to provide a surface finish of 125 microinches or smoother;
• and
• heat treating the component having the coating applied to the substrate at a temperature from about 2000° F. to about 2100° F. for a time of 1 to about 16 hours to achieve a sound metallurgical bond between the substrate and the coating.