Department of Materials Science, Montanuniversität Leoben, Franz-Josef-Strasse 18, 8700, Leoben, Austria.
Materials Chemistry, RWTH Aachen University, Kopernikusstraße 10, 52074, Aachen, Germany.
Sci Rep. 2023 May 22;13(1):8244. doi: 10.1038/s41598-023-34768-7.
In this work, we studied the energetics of diffusion-related quantities of transition-metal impurities in TiN, a prototype ceramic protective coating. We use ab-initio calculations to construct a database of impurity formation energies, vacancy-impurity binding energies, migration, and activation energies of 3d and selected 4d and 5d elements for the vacancy-mediated diffusion process. The obtained trends suggest that the trends in migration and activation energies are not fully anti-correlated with the size of the migration atom. We argue that this is caused by a strong impact of chemistry in terms of binding. We quantified this effect for selected cases using the density of electronic states, Crystal Orbital Hamiltonian Population analysis, and charge density analysis. Our results show that the bonding of impurities in the initial state of a diffusion jump (equilibrium lattice position), as well as the charge directionality at the transition state (energy maximum along the diffusion jump pathway), significantly impact the activation energies.
在这项工作中，我们研究了过渡金属杂质在 TiN 中的扩散相关量的能量学，TiN 是一种典型的陶瓷防护涂层。我们使用从头算计算构建了一个杂质形成能、空位-杂质结合能、3d 元素以及空位介导扩散过程中选定的 4d 和 5d 元素的迁移和激活能的数据库。所得趋势表明，迁移和激活能的趋势与迁移原子的大小不完全反相关。我们认为这是由于结合能方面的化学性质的强烈影响。我们使用态密度、晶体轨道哈密顿人口分析和电荷密度分析对选定情况进行了量化。我们的结果表明，扩散跳跃初始状态（平衡晶格位置）中杂质的键合以及过渡状态（沿扩散跳跃途径的能量最大值）的电荷方向性，显著影响激活能。
