The thermal and mechanical properties of hafnium orthosilicate: Experiments and first-principles calculations
The thermal and mechanical properties of hafnium orthosilicate: Experiments and first-principles calculations
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DOI：
10.1016/j.mtla.2020.100793
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发表时间：
2020-08-01
期刊：
影响因子：
3.4
通讯作者：
Esfarjani, Keivan
中科院分区：
文献类型：
--
作者：
Ding, Zhidong;Ridley, Mackenzie;Esfarjani, Keivan
正硅酸铪（HfSiO 4：SiO2）已被提议作为环境阻挡涂层（EBC）材料以在高温下保护硅和硅基陶瓷材料，并作为微电子器件中的候选介电材料。它可以在二氧化硅（SiO2）和氧化铪（HfO 2）之间的界面处自然形成。当用作EBC时，其热膨胀系数（CTE）应与保护层（例如硅和SiC复合材料）的热膨胀系数相匹配，以降低存储的弹性应变能，从而降低这些系统失效的风险。在这项工作中，的物理，机械，热力学和热输运性质已被调查使用密度泛函理论（DFT）计算和实验评估相结合。在300 ~ 1500 K温度范围内，用准谐近似计算的平均线膨胀系数（CTE）从3.06 × 10（-6）K-1增加到6.36 × 10（-6）K-1，与X射线衍射点阵参数和X射线衍射仪的测量结果一致。在300 K时，根据玻尔兹曼输运理论预测的热导率约为16.1 W/m.K。使用热盘和激光闪光测量的样品的热导率给出了13.3 W/m. K的值。该略低的值是预期的，并且指示实验样品中的残余无序，其在理论分析中不存在。第一性原理计算和纳米压痕技术分别用于评估环境温度下的弹性常数和体积模量。通过这两种方法获得的弹性性能同意在5%以内，验证了计算方法及其未来用于其他氧化物或硅酸盐的热机械性能的研究。
Hafnium orthosilicate (HfSiO4 : hafnon) has been proposed as an environmental barrier coating (EBC) material to protect silicon and silicon-based ceramic materials at high temperatures and as a candidate dielectric material in microelectronic devices. It can naturally form at the interface between silicon dioxide (SiO2) and hafnia (HfO2). When used as an EBC its coefficient of thermal expansion (CTE) should match that of the protecting layer (e.g. silicon and SiC composites) to reduce the stored elastic strain energy, and thus the risk of failure of these systems. In this work, the physical, mechanical, thermodynamic and thermal transport properties of hafnon have been investigated using a combination of density functional theory (DFT) calculations and experimental assessments. The average linear coefficient of thermal expansion (CTE) calculated using the quasi-harmonic approximation increase from 3.06 x 10(-6) K-1 to 6.36 x 10(-6) K-1, as the temperature increases from 300 to 1500 K, in agreement with both X-ray diffraction lattice parameter and dilatometry measurements. The predicted thermal conductivity from Boltzmann transport theory is approximately 16.1 W/m.K at 300 K. The thermal conductivity of our samples using both hot disk and laser flash measurements gave a value of 13.3 W/m.K. This slightly lower value is expected and is indicative of residual disorder in the experimental samples, which is absent in the theoretical analysis. First-principles calculations and nanoindentation techniques are used to assess the ambient temperature elastic constants and bulk modulus respectively. The elastic properties obtained by both approaches agreed to within 5%, validating the computational approach and its future use for the study of the thermomechanical properties of other oxides or silicates.