Environmental and compositional factors often influence the hot-corrosion behavior of alloys and
coatings used in gas turbine engine applications. This paper examines the effects of environmental
factors such as salt deposition rate, gas composition, and extent of oxidation on the hot-corrosion
resistance (Type I-900oC and Type II-704oC) of Ni-based alloys and coatings. It also evaluates the
effects of Pt-modified ß-NiAl alloy composition on hot-corrosion resistance. Both types of hot corrosion
conditions were simulated by depositing Na2SO4 salt on the test samples and then exposing those
samples to a catalyzed O2:SO2 atmosphere. It was found that Type I hot corrosion resistance decreased
with increase in salt deposition rate up to 8 mg/cm2; however, no measurable hot corrosion was
observed when the sample was completely buried in a salt. It was also found that the Type II hot
corrosion resistance of Pt-modified Ni-based alloys is very sensitive to both alloy and gas composition.