La2Zr2O7 based high entropy ceramic with a low thermal conductivity and enhanced CMAS corrosion resistance

Herein, five new La 2 Zr 2 O 7 based high-entropy ceramic materials, such as (La 0.2 Ce 0.2 Gd 0.2 Y 0.2 Er 0.2 ) 2 Zr 2 O 7 , (La 0.2 Ce 0.2 Gd 0.2 Er 0.2 Sm 0.2 ) 2 Zr 2 O 7 , (La 0.2 Gd 0.2 Y 0.2 Er 0.2 Sm 0.2 ) 2 Zr 2 O 7 , (La 0.2 Ce 0.2 Y 0.2 Er 0.2 Sm 0.2 ) 2 Zr 2 O 7 , (La 0.2 Ce 0.2 Gd 0.2 Y 0.2 Sm 0.2 ) 2 Zr 2 O 7 ), were synthesized using a sol-gel and high-temperature sintering (1000 °C) method. The spark plasma sintered (SPS) (La 0.2 Ce 0.2 Gd 0.2 Er 0.2 Sm 0.2 ) 2 Zr 2 O 7 pellet shows a low thermal conductivity of 1.33 W m -1  K -1 at 773 K, and it also exhibits better CaO–MgO–Al 2 O 3 –SiO 2 corrosion resistance than that of Y 2 O 3 stabilized ZrO 2 . It shows that (La 0.2 Ce 0.2 Gd 0.2 Er 0.2 Sm 0.2 ) 2 Zr 2 O 7 has a promising application potential as a thermal barrier coating .