Corrosion behavior of thermal barrier coatings exposed to NaCl plus water vapor at 1050 °C

In the present investigation, NiCrAlY coating with the composition of Ni-24Cr-6Al-0.7Y is deposited on a nickel-based superalloy by low-pressure plasma spraying, and the top coating, ZrO 2 , partially stabilized with Y 2 O 3 (7 wt.%), is deposited on NiCrAlY coating by air plasma spraying. The cyclic corrosion behavior of NiCrAIY+YSZ coating exposed to NaCI plus water vapor has been investigated under atmospheric pressure at 1050 °C. The result shows that the cyclic oxidation life of NiCrAIY+YSZ coating in the presence of NaCl plus water vapor was shortened compared with that in NaCI vapor. The failure of the coating mainly happened near the interface between the bond coat and YSZ. The accelerated failure mechanism has been discussed based on the experimental results and thermodynamics.