Effect of zirconium addition on cyclic oxidation behavior of platinum-modified aluminide coating on nickel-based superalloy

The effect of Zr addition to Pt-modified aluminide coatings was investigated. Zr coatings on Pt-modified aluminide coatings were deposited by EB-PVD and heat treatments were conducted. SEM analysis indicated that Zr was situated at the surface and grain boundary near the surface as an agglomerated form of the NiAl–Zr alloy, which affected the growth rate of the thermally grown oxide during cyclic oxidation. Also, the interface and surface roughnesses of Zr-added Pt-modified aluminide coatings were smaller than that of the Pt-modified aluminide coating. Also, phase stabilities of Zr-added Pt-modified aluminide coating were enhanced as compared with the Pt-modified aluminide coating. Because Zr-added Pt-modified aluminide coatings had resistance to spallation of TGO caused by Zr-rich oxide pegs, they showed better resistance to cyclic oxidation than Pt-modified aluminide coating without Zr addition.