Phase transition and thermal conductivity study of perovskite compounds SrBo3 (B = Zr and Hf) using PHONO3PY code for application as thermal barrier coatings

The phase transition and thermal conductivity of perovskite compounds Sr B O 3 ( B = Zr and Hf), which are potential materials for thermal barrier coatings, were investigated using the PHONO3PY code. A novel perspective is presented, suggesting that the expansion of the octahedra formed by six oxygen ions can suppress the phase transitions in perovskites AB O 3 . This perspective also explains the phenomenon of phase transition suppression when SrZrO 3 is doped with rare-earth elements (REEs). Furthermore, based on this perspective, specific REEs can be selected to effectively restrain the phase transitions of SrZrO 3 and SrHfO 3 . For the orthorhombic SrZrO 3 and SrHfO 3 structures, La and Ce exhibit the highest efficiency, respectively. Regarding the cubic structure of SrZrO 3 , Ce is found to be the most effective. Lastly, in terms of reducing the thermal conductivity of SrHfO 3 , La and Pr demonstrate the greatest capability. These results are consistent with those obtained using Slack’s method. Additionally, a combination of La, Ce, Pr, Nd, Sm, Eu, Gd, and Tb is the most efficient in decreasing the thermal conductivity of SrHfO 3 .