Yb doping effects on CMAS corrosion resistance of Yb-doped GdPO4 by first-principles calculation and experimental investigation

GdPO4 is an attractive CMAS-resistant thermal barrier coating material due to the rapid GdPO4/CMAS reaction forming an interface reaction layer. However, this layer is weakly adhered to the GdPO4 surface weakening its function on inhibiting CMAS penetration. In this study, Yb-doped GdPO4 (Gd0.75Yb0.25PO4) was explored and its CMAS corrosion resistance was investigated. The Yb doping effects on the corrosion products formation enthalpy, the interface reaction layer construction and evolution, and the adhesion of the layer to Yb-doped GdPO4 were clarified based on first-principles calculation and experimental investigation. Yb-doped GdPO4 is verified to be more resistant to CMAS attack than GdPO4.