Low thermal conductivity and a ferroelastic tetragonal-monoclinic phase transition are essential for the use of YTaO₄ in thermal barrier coatings. The phonon scattering mechanism of HfO₂ alloying YTaO₄ is elucidated via the analysis of microstructural characteristics, and a limit thermal conductivity (1.3 W·m⁻¹·K⁻¹) is achieved. Furthermore, a revised model is developed to successfully derive high-temperature phonon thermal conductivity, showing a decrease in the phonon scattering coefficient as strain field fluctuations decrease. This proves that the phonon scattering coefficient is temperature dependent. Atomic weight disorder plays a significant role in thermal conductivity reduction, whereas HfO₂ alloying enhances lattice symmetry and weakens the phonon scattering, and thus mitigates thermal conductivity reduction. Additionally, domain boundary width and spacing mismatch between neighboring domains cause the scattering of phonons and further reduce the thermal conductivity. Finally, evidence of a diffusive domain boundary validates that tetragonal-monoclinic transition is a second-order process.

_{低热导率和铁弹性四方-单斜相变对于 YTaO 4}在热障涂层中的应用至关重要。通过微观结构特征分析阐明了HfO ₂合金化YTaO ₄的声子散射机制，并实现了极限导热系数（1.3 W·m ^-1 ·K ^{-1 ）。}此外，还开发了一个修改后的模型，成功推导了高温声子热导率，表明随着应变场波动的减小，声子散射系数减小。这证明声子散射系数与温度有关。原子量无序在热导率降低中起着重要作用，而 HfO₂合金化增强了晶格对称性并削弱了声子散射，从而减轻了热导率的降低。此外，相邻域之间的域边界宽度和间距不匹配会导致声子散射并进一步降低热导率。最后，扩散域边界的证据证实四方-单斜转变是一个二阶过程。