Failure behaviour of Y2O3-ZrO2 thermal barrier coatings under the combined effects of hot corrosion and thermal shock

Abstract

ABSTRACT Y2O3-ZrO2 thermal barrier coatings on a GH2132 alloy were fabricated by atmospheric plasma spraying method. Failure behaviours of the thermal barrier coatings under the combined condition of hot corrosion and thermal shock were investigated. Surface and cross-sectional morphologies of thermal barrier coatings before and after exposures were assessed by using scanning electron microscopy. It was established that the main failure mode was the formation of net-like cracks in coatings and penetrating cracks to the bond coat/substrate interface. By detailed consideration to the analysis of X-ray diffraction and morphologies, the effect of hot corrosion on the failure of thermal barrier coatings was inferred to be due to the induced stress during the cooling stage of the combined condition, which was prone to induce the crack formation.