School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, 541004, P.R. China.
Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, Guilin, 541004, P.R. China.
Sci Rep. 2017 Jul 26;7(1):6535. doi: 10.1038/s41598-017-06658-2.
Changes in the stability, hydrogen diffusion, and mechanical properties of the NbH phases from Ni-doping was studied by using first-principles methods. The calculation results reveal that the single H atom adsorption is energetically favorable at the tetrahedral interstitial site (TIS) and octahedral interstitial site (OIS). The preferred path of H diffusion is TIS-to-TIS, followed by TIS-to-OIS in both NbH and NbNiH. Ni-doping in the NbNiH alloy lowers the energy barrier of H diffusion, enhances the H-diffusion coefficient (D) and mechanical properties of the NbH phase. The value of D increases with increasing temperature, and this trend due to Ni doping clearly becomes weaker at higher temperatures. At the typical operating temperature of 400 K, the D value of NbNiH (TIS) is about 1.90 × 10 m/s, which is about 80 times higher than that of NbH (TIS) (2.15 × 10 m/s). Our calculations indicated that Ni-doping can greatly improve the diffusion of H in Nb.
通过第一性原理方法研究了 Ni 掺杂对 NbH 相稳定性、氢扩散和力学性能的影响。计算结果表明，单氢原子在四面间隙位（TIS）和八面体间隙位（OIS）吸附是能量有利的。在 NbH 和 NbNiH 中，H 扩散的优先路径是 TIS 到 TIS，然后是 TIS 到 OIS。Ni 掺杂降低了 NbNiH 合金中 H 的扩散能垒，提高了 NbH 相的 H 扩散系数（D）和力学性能。D 值随温度升高而增加，由于 Ni 掺杂，这种趋势在较高温度下明显减弱。在典型的工作温度 400 K 下，NbNiH（TIS）的 D 值约为 1.90×10 m/s，约为 NbH（TIS）（2.15×10 m/s）的 80 倍。我们的计算表明，Ni 掺杂可以大大提高 H 在 Nb 中的扩散。
