Investigation on CMAS corrosion resistance of Sc₂O₃-Y₂O₃ co-stabilized ZrO₂ thermal barrier coating material by tunable design with Gd-doping

It is well known that the traditional Y₂O₃ stabilized ZrO₂ thermal barrier coatings (TBCs) are vulnerable to calcium-magnesium-alumina-silicate (CMAS) attack. With the aim of improving the CMAS corrosion resistance of TBCs, a series of Gd-doping Sc₂O₃-Y₂O₃ co-stabilized ZrO₂ (GdScYSZ) materials were tailored and prepared in this study. The results suggested that only when the doping amount of Gd³⁺ reached the threshold of apatite phase formation, the excellent CMAS corrosion resistance of TBCs can be achieved. Therefore, the 20GdScYSZ material had outstanding CMAS corrosion resistance, in which a dense interwoven protective layer that consisted of acicular apatite grains and c-ZrO₂ grains was formed to resist the corrosion and prevent the penetration of CMAS. In addition, the wettability of the reaction interface was investigated by first-principles calculation. Our work provides a valuable approach for designing TBC materials with remarkable CMAS corrosion resistance.