Effects of piezo-spectroscopic coefficients of 8 wt.% Y2O3 stabilized ZrO2 on residual stress measurement of thermal barrier coatings by Raman spectroscopy

Abstract

Abstract By using specially designed freestanding 8 wt.% Y 2 O 3 stabilized ZrO 2 (8YSZ) specimens, a linear relationship is found between the Raman peak shift, Δ ω , and applied uniaxial compressive stress, σ u , i.e., Δ ω = Π u σ u with Π u being the piezo-spectroscopic coefficient. The linear relationship is used to determine the in-plane residual stress in air plasma-sprayed 8YSZ thermal barrier coatings (TBCs). It is shown that the Π u of the 8YSZ is an exponential function of the thermal cycle N for a given thermal cycling process: Π u = 37.6exp(− N /25.9) + 13. Based on these two relationships, the actual residual stress of 8YSZ TBCs determined by the Raman spectroscopy method is quantitatively consistent with that obtained by the X-ray diffraction.