CMAS corrosion behavior of Sc doped Gd2Zr2O7 /YSZ thermal barrier coatings and their corrosion resistance mechanisms

YSZ thermal barrier coatings (TBCs) are vulnerable to calcium-magnesium-alumina-silicate (CMAS) attack, and a CMAS resistant TBC of Sc doped Gd2Zr2O7/YSZ are developed in this study. At 1250 ℃, corrosion products form a reaction layer at the CMAS/coating interface, which largely suppresses CMAS further infiltration. Compared with Gd2Zr2O7, Sc doped Gd2Zr2O7 has a higher ability to keep its lattice structure in the presence of CMAS, which is beneficial to maintain the coating microstructure under CMAS conditions, alleviating the coating degradation. First-principles calculation was conducted to investigate the corrosion products formation mechanisms, and the characteristics of CMAS/reaction layer and reaction layer/coating interfaces. [Display omitted] •CMAS corrosion behavior of Sc doped Gd2Zr2O7/YSZ TBCs were studied.•At 1250 ℃, a reaction layer formed on the coating surface, which largely suppressed CMAS further penetration.•Compared with Gd2Zr2O7, Sc doped Gd2Zr2O7 had a higher ability to keep its lattice structure in the presence of CMAS.•Sc doping in Gd2Zr2O7 TBCs was beneficial to maintain the coating microstructure and improve the CMAS resistance.•Corrosion products formation mechanisms and coating interface characteristics were discussed by first-principles calculation.