Thermal properties of A‐site and B‐site co‐doped rare earth zirconates

Abstract A 2 B 2 O 7 ‐type rare‐earth zirconates have garnered significant attention due to their low thermal conductivity. The reduction of thermal conductivity can be effectively achieved by doping with various rare earth elements at the A‐site; however, there has not been a notable enhancement in the coefficient of thermal expansion. Consequently, a novel zirconate/cerate, co‐doped at both the A‐site and B‐site, was synthesized, exhibiting lower thermal conductivity alongside a higher thermal expansion coefficient. The study of the coefficient of thermal expansion of this series of samples revealed that electronegativity and average cation radius together affect the coefficient of thermal expansion. Furthermore, thermal conductivity investigations indicated that the zirconate devoid of Ce doping retains favorable thermal conductivity across all temperatures. There is a negative correlation between thermal conductivity and mass disorder for samples other than (Nd 1/5 Sm 1/5 Eu 1/5 Gd 1/5 Lu 1/5 ) 2 (Zr 1/2 Ce 1/2 ) 2 O 7 (HZC). HZC demonstrates a better integrated thermal performance than the other two zirconates, suggesting its potential as a new type of thermal barrier coating material with significant development prospects.