Effect of Er dopant on the corrosion resistance of YSZ in CMAS melt: experimental and first-principles study

Chemical effect of rare earth element erbium (Er) doped in yttria-stabilized zirconia (YSZ) is studied via experimental and theoretical methods in calcium-magnesium-alumino-silicate (CMAS) melt. It is found that the penetration depth of YSZ doped by Er element is only 10.75 ± 1.13 μm, which is smaller than that of undoped YSZ (21.97 ± 1.52 μm). Theoretical results show that a decrease in the thermal expansion coefficient of YSZ(Er) and in the Griffith rupture work of CMAS/YSZ(Er) and CMAS/ZrSiO4 weakens their thermal stress and adhesive strength. And doped Er element in YSZ can setback the diffusion of Y elements and enhance the diffusion of Si ↔ Zr elements in the YSZ(Er) TBC, which can slow down the phase transition from t-ZrO2 to c-ZrO2 and promote the formation of the ZrSiO4 corrosion products to block the interface pores within a YSZ(Er) structure. Thus, our findings open another way to probe the advantage of rare earth element doped in thermal barrier coating.