Zirconium silicate growth induced by the thermochemical interaction of yttria-stablized zirconia coatings with molten CMAS deposits

摘要

We report on the microstructure evolution of yttria-stablized zirconia (YSZ) corroded by molten deposits of Ca10Mg7Al13Si20 (CMAS). The CMAS corrosion induces significant zirconium silicate (ZrSiO4) growth across the entire YSZ coating and causes dramatic microstructure changes marked by the complete disappearance of the feather-like structure of the columnar grains in the upper region of the coating and disintegration of the parent columnar grains into an equiaxed grains near the YSZ/Al2O3 interface. CMAS infiltration along the intercolumnar gaps results in ZrSiO4 growth into YSZ grains. Curvature-driven infiltration of the molten CMAS along ZrSiO4/YSZ interfaces gives rise to dendritic-like ZrSiO4 growth.