Thermophysical performances of Sm2O3-doped Gd3TaO7 oxides for thermal barrier coatings
Weiwei Sang, Zhang Hongsong, Zhang Hongsong, Shuaixia Liu, Haoming Zhang, Haoming Zhang, Bo Ren, An Tang, Xiaoge Chen, Wenbo Xie, Ruiyi Hou, Hongjun Ma, Siqi Li
Abstract
To investigate the effect of Sm 3 O 3 addition on the thermophysical performances of Gd 3 TaO 7 , (Gd 1−x Sm x ) 3 TaO 7 oxides were synthesised using sol-gel and sintering with high-temperature technologies, and their thermophysical properties were researched. The investigations exhibit that the obtained powders comprise well-distributed particles, and the bulk specimens have densified microstructures. The obtained ceramics have single pyrochlore-lattice. Owing to varied scattering strength coefficient of phonon caused by the differences in ionic radius and mass between the substituting and substituted elements, the value of thermal conductivity of (Gd 1−x Sm x ) 3 TaO 7 decreases firstly and further increases with the increase fraction of Sm 2 O 3 . The coefficient of thermal expansion of (Gd 1−x Sm x ) 3 TaO 7 is ameliorated owing to the higher ionic radius of Sm 3+ than Gd 3+ . Except for Sm 3 TaO 7 , the synthesised ceramics display outstanding lattice steadiness up to 1400 °C.