A novel entropy‐regulating strategy to enhance the calcium‐magnesium‐aluminum‐silicate corrosion resistance of rare‐earth cerates

Abstract With the development of the new generation of gas turbines, the demand for thermal barrier coating (TBC) materials has increased, and the requirements for their comprehensive properties have become more stringent. To meet this challenge, a new type of high‐entropy (La 0.2 Y 0.2 Gd 0.2 Yb 0.2 Lu 0.2 ) 2 Ce 2 O 7 ceramic was prepared in this work by one‐step solid‐state synthesis and sintering at 1600°C for 15 h. The new high‐entropy ceramic has a fluorite structure, low thermal conductivity (1.13 W·m −1 ·K −1 at 1473 K), and thermal expansion coefficient (11.58 × 10 −6 K −1 ) matching YSZ and nickel‐based superalloys. After reacting with CMAS at 1300°C for 96 h, the thickness of the reaction layer is only 13.93 µm, showing good corrosion resistance to CMAS. These results demonstrate that (La 0.2 Y 0.2 Gd 0.2 Yb 0.2 Lu 0.2 ) 2 Ce 2 O 7 is a promising TBC material with good resistance to CMAS corrosion.