Study on the effect of CMAS and NaCl melting sequence on the corrosion resistance of thermal barrier coatings

Calcium-magnesium-alumina-silicate (CMAS) and/or molten salt corrosion has attracted increased attentions, which is an important cause of thermal barrier coatings (TBCs) failure. In this study, the effect of CMAS and NaCl melting sequence on the corrosion mechanisms of the Yttria-stabilised zirconia (YSZ) TBCs was revealed through experiments and finite element simulations. The YSZ TBCs were prepared via an atmospheric plasma spraying. Subsequently, the CMAS and NaCl corrosion experiments of the TBCs were conducted at 1250℃. The results indicated that the melting sequence of CMAS and NaCl could affect the TBCs failure mode. The coating failure modes of after CMAS+NaCl mixed corrosion and firstly melting NaCl, with secondly melting CMAS corrosion were the buckling failure, and conversely the coating failure mode was the spalling failure. This study provides data support for the optimization of TBC system in complex corrosive environments.