Failure mechanism of plasma sprayed Tb-YSZ coating under NaCl high-low temperature cyclic corrosion.

Thermal barrier coatings (TBC) face great challenges in the marine environment. In this paper, the Tb-doped yttrium stabilized zirconia (Tb-YSZ) coating was prepared by atmospheric plasma spraying. The corrosion behaviour of the Tb-YSZ coating was tested in an alternating marine environment of 600 °C and room temperature. The high temperature oxidation-electrochemical reaction caused by corrosion results in the thickening of thermal growth oxide (TGO), which is beneficial for resisting corrosion in marine environment. However, the thickening of TGO from 0.9 μm to 4.8 μm increases the equivalent internal stress by 48 %, leading to coating spalling failure. [Display omitted] • In the alternating high and low temperature maritime environment, thermal barrier coatings are more prone to fail. • Thermal growth of oxides (TGO) contributed to the coatings' resilience to sea corrosion. • The TGO caused a massive stress mismatch, resulting in flaking and breakdown of the coating. [ABSTRACT FROM AUTHOR]