Das Prima, Jahan N, Ali M A
Department of Physics, Chittagong University of Engineering and Technology (CUET) Chattogram-4349 Bangladesh
RSC Adv. 2023 Feb 14;13(8):5538-5556. doi: 10.1039/d2ra07468k. eCollection 2023 Feb 6.
In this study, we performed the first-principles calculations to study the 211 MAX phase carbides: NbAC (A = Ga, Ge, Tl, Zn, P, In, Cd, and Al). The structural characteristics are in good agreement with those of the prior studies. The mechanical behavior has been explored by calculating the stiffness constants, elastic moduli, and Vickers hardness. The stiffness constants and phonon dispersion curves were used to check the structural stability of the selected compounds. 2D and 3D plotting of elastic moduli and calculated anisotropy indices disclosed the anisotropy of the elastic properties. We utilized the Mulliken atomic and bond overlap population to explain the mixture of ionic and covalent bonding among these carbides. The metallic behavior has been confirmed by calculating the band structure and density of states (DOS). Partial DOS was also used to discuss the bonding nature and strength among the different states. The optical properties of these phases have also been computed and analyzed to reveal possible relevance in diverse fields. The Debye temperature ( ), Grüneisen parameter (), melting temperature ( ), and minimum thermal conductivity ( ) were studied to bring out their possible relevance in high-temperature technology. The outcomes of this research indicate that the titled carbides are suitable for use as solar radiation-protecting coating and thermal barrier coating (TBC) materials.
在本研究中，我们进行了第一性原理计算，以研究211 MAX相碳化物：NbAC（A = Ga、Ge、Tl、Zn、P、In、Cd和Al）。其结构特征与先前的研究结果高度吻合。通过计算刚度常数、弹性模量和维氏硬度，对其力学行为进行了探究。利用刚度常数和声子色散曲线来检验所选化合物的结构稳定性。弹性模量的二维和三维绘图以及计算得到的各向异性指数揭示了弹性性质的各向异性。我们利用穆利肯原子重叠布居和键重叠布居来解释这些碳化物中离子键和共价键的混合情况。通过计算能带结构和态密度（DOS）证实了其金属行为。部分态密度也用于讨论不同态之间的键合性质和强度。还对这些相的光学性质进行了计算和分析，以揭示其在不同领域可能的应用价值。研究了德拜温度（ ）、格林艾森参数（ ）、熔点温度（ ）和最小热导率（ ），以阐明它们在高温技术中可能的应用价值。本研究结果表明，上述碳化物适合用作太阳辐射防护涂层和热障涂层（TBC）材料。
