Thermal barrier coating materials require high phase stability, low thermal conductivity, and a thermal expansion coefficient that matches the bonding layer. Cation doping is a highly efficient method for enhancing the thermophysical and mechanical characteristics of materials used in thermal barrier coatings. The thermophysical and mechanical properties, as well as the phase stability at high temperatures of ceramic materials doped with Yb3+ in gadolinium zirconate, are examined by utilizing first principles calculations and solid-state reaction methods. As the Yb3+ content increases, the grain average particle size of gadolinium zirconate ceramics first decreases and then increases. Given that a smaller grain size results in more grain boundaries, thereby reducing the thermal conductivity of the material, it can be inferred that Yb0.20 ((Gd0.8Yb0.2)2Zr2O7) with the smallest grain size exhibits lower thermal conductivity. As the Yb3+ content increases, both the calculated and experiment results suggest the Young’s modulus of gadolinium zirconate initially declines to its minimum value when the Yb3+ content is 0.5 and subsequently experiences a little increase. Furthermore, as the concentration of Yb3+ increases, the material initially experiences a drop in both hardness and fracture toughness, followed by a subsequent increase. Both the calculation and experimental results indicate that the thermal conductivity of gadolinium zirconate initially decreases and then increases. Among the different compositions, Gd1.5Yb0.5Zr2O7 demonstrates the minimum thermal conductivity, measuring 1.029 W/(m⸱K) according to the Clark model and 1.152 W/(m⸱K) according to the Cahill model. At a temperature of 1273 K, the experimental results demonstrated that (Gd0.8Yb0.2)2Zr2O7 has the lowest thermal conductivity of 1.415 W/(m·K). Furthermore, both the calculated and experimental thermal expansion coefficients of the material decrease first until the Yb3+ concentration is 0.5 and then increase slightly when the Yb3+ content increases. Moreover, gadolinium zirconate ceramics have demonstrated a consistent single-phase fluorite structure, excellent stability at high temperatures, and remarkable structural integrity during repeated heating and cooling cycles. The calculation results exhibit strong congruence with the experimental data. The objective of this work is to improve the thermophysical and mechanical properties of gadolinium zirconate ceramics for their application as materials for thermal barrier coatings.

中文翻译：

---

Yb3+对锆酸钆陶瓷热物理和力学性能的影响：第一性原理计算和实验研究


热障涂层材料要求高相稳定性、低导热率以及与粘结层相匹配的热膨胀系数。阳离子掺杂是增强热障涂层材料的热物理和机械特性的高效方法。利用第一原理计算和固相反应方法研究了锆酸钆中掺杂 Yb3+ 的陶瓷材料的热物理和机械性能以及高温下的相稳定性。随着Yb3+含量的增加，锆酸钆陶瓷的晶粒平均粒径先减小后增大。鉴于较小的晶粒尺寸会导致更多的晶界，从而降低材料的热导率，因此可以推断晶粒尺寸最小的Yb0.20（（Gd0.8Yb0.2）2Zr2O7）表现出较低的热导率。随着Yb3+含量的增加，计算结果和实验结果都表明，当Yb3+含量为0.5时，锆酸钆的杨氏模量首先下降到最小值，随后略有增加。此外，随着 Yb3+ 浓度的增加，材料的硬度和断裂韧性最初会下降，随后又增加。计算和实验结果均表明锆酸钆的热导率先减小后增大。在不同的成分中，Gd1.5Yb0.5Zr2O7 表现出最小的导热率，根据 Clark 模型测量为 1.029 W/(m⸱K)，根据 Cahill 模型测量为 1.152 W/(m⸱K)。在1273 K温度下，实验结果表明（Gd0.8Yb0.2)2Zr2O7的导热系数最低，为1.415 W/(m·K)。此外，材料的计算热膨胀系数和实验热膨胀系数在Yb3+浓度达到0.5时先减小，然后当Yb3+含量增加时略有增加。此外，锆酸钆陶瓷表现出一致的单相萤石结构、优异的高温稳定性以及在重复加热和冷却循环过程中显着的结构完整性。计算结果与实验数据表现出很强的一致性。这项工作的目的是提高锆酸钆陶瓷的热物理和机械性能，使其用作热障涂层材料。