Properties and CMAS resistance of Gd₂Zr₂O₇ thermal barrier coating

Gd₂Zr₂O₇ was synthesized by high-temperature solid-phase synthesis using zirconia （ZrO₂） and Gadolinium（Ⅲ） oxide （Gd₂O₃） as raw materials. The crystal structure， thermal expansion coefficient， microstructure， mechanical properties and sintering resistance of Gd₂Zr₂O₇ were systematically studied by XRD， thermal dilatometer， SEM and Vickers hardness tester. The results showed that Gd₂Zr₂O₇ exhibited a high coefficient of thermal expansion （TEC） and good sintering resistance， but its mechanical properties were poor. After 4 h of hot corrosion， the corrosion depth reached 41.56 μm； After 12 h of hot corrosion， the corrosion depth reached 132.30 μm. At high temperature， Gd₂Zr₂O₇ reacted with molten CMAS to form a dense layer of Ca₂Gd₈（SiO₄）₆O₂， which hindering the further penetration of CMAS.