Investigation of Gd2(Hf0.7Ti0.3)2O7 ceramics as a potential thermal barrier coating

Abstract In this study, Gd₂(Hf₀.₇Ti₀.₃)₂O₇ ceramics were synthesized by a high‐temperature solid‐state method, and the feasibility of using it as thermal barrier coating was systematically studied. This study primarily investigated the thermal physical properties, mechanical properties, and calcium–magnesium–alumina–silicate oxides (CMAS) corrosion resistance of the Gd₂(Hf₀.₇Ti₀.₃)₂O₇ ceramic bulk. The results indicated that the thermal expansion coefficient of Gd₂(Hf₀.₇Ti₀.₃)₂O₇ ceramics was close to that of 6∼8wt% yttria‐stabilized zirconia (YSZ). At 1000°C, the thermal conductivity of Gd₂(Hf₀.₇Ti₀.₃)₂O₇ (1.43 W/(m·K)) was about 43% lower than that of YSZ (2.5 W/(m·K)). Furthermore, Gd₂(Hf₀.₇Ti₀.₃)₂O₇ also exhibited significant advantages in mechanical properties. Its hardness, fracture toughness, and Young's modulus are 10.00 ± 0.28 GPa, 2.53 ± 0.06 MPa·m¹/ 2 , and 124.91 ± 17 GPa, respectively. In addition, Gd₂(Hf₀.₇Ti₀.₃)₂O₇ exhibited excellent CMAS corrosion resistance, making it a promising candidate for the next generation of thermal barrier coating materials.