Multidisciplinary approach for investigating the hot corrosion behavior of thermal barrier coatings

Abstract

Herein, we propose a new multidisciplinary approach for investigating the corrosion behavior of thermal barrier coatings, combining the thermal-gradient mechanical fatigue method with hot corrosion tests. Corrosive salts (Na2SO4; V2O5) of varying concentrations (10−20 mg/cm2) were deposited on the surface of yttria-stabilized zirconia (YSZ) coatings to evaluate the microstructural changes occurring during the reaction, via thermal graded mechanical fatigue tests. The tests were conducted at a surface temperature of 1150 °C in 10 min cycles and underwent applied uniaxial tensile loads. The corrosion tests show that the ZrV2O7 plays an important role as an intermediate in the collapse of the lamellar structures during the reaction, which results from the repetitive precipitation of V2O5 and m-ZrO2 from the ZrV2O7. The microstructure of corroded YSZ coatings exhibited a different degradation mechanism under a thermomechanical environment, compared with the testing under isothermal atmospheric conditions.