US Patent 6929868 SRZ-susceptible superalloy article having a protective layer thereon

A protected article includes a substrate having a substrate surface and made of a substrate nickel-base superalloy that is susceptible to the formation of a secondary reaction zone, as when contacted by an aluminum-containing layer having more than about 20 percent by weight aluminum. A protective layer contacts the substrate surface. The protective layer is of a different composition than the substrate and is made of a protective-layer nickel-base superalloy having from about 7 to about 12 percent by weight aluminum. Preferably, a thermal barrier coating system including a ceramic layer overlies and contacts the protective layer.