Hot corrosion behavior of reactive-element modified aluminide coatings: The importance of the substrate carbides

Abstract

Aluminide coatings were developed on a nickel alloy with the addition of RE (Ce, Y, La, and Zr) oxides to the coating powder mixture. The specimens were aluminized at 760 °C for 2 h and diffusion annealed at 1050 °C for 4 h. The characterization of the specimens confirmed the formation of NiAl phase on all the specimens. The hot corrosion test at 900 °C using a 2 mg/cm2 loading of the Na2SO4 -NaCl-V2 O5 mixture showed a similar general protective behavior along with different degrees of local penetration at the surface carbide locations.