SHAO Yating, LIU Yanbo, WANG Quansheng, NING Xianjin
(School of materials science and engineering Beijing Institute of Technology, Beijing 100081, China)
Abstract: The most popular material identified for the function of heat insulation is 7-8wt.% yttria stabilized zirconia (YSZ). Long-term exposure beyond 1200 °C leads to sintering and catastrophic phase transformation of the YSZ coating, which has been difficult to meet the work requirements of aircraft engine. Perovskite Ba(B’1/3Ta2/3)O3(B’=Mg, Zn, Ni) materials have promising bulk properties for thermal barrier coating (TBC) applications at high temperature. First-principles density-functional theory (DFT) was applied to optimize the crystal structure and calculate the electronic structure among BMT, BZT and BNT. Due to the absence of d-orbital in Mg, there is no obvious covalent interaction between Mg and other irons in BMT. However, the covalent interactions among B’, O and Ta are distinctly shown in BZT and BNT. Furthermore, it is notable that the covalent interaction between Ta and O in BZT is less intensive than that in BMT and BNT.
Key words: Ba(B’1/3Ta2/3)O3; high-temperature stability; electronic structures; first-principles