Self-diffusion and macroscopic diffusion of hydrogen in amorphous metals from first-principles calculations.
Self-diffusion and macroscopic diffusion of hydrogen in amorphous metals from first-principles calculations.
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DOI：
10.1063/1.3158619
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发表时间：
2009-06
期刊：
影响因子：
--
通讯作者：
Shiqiang Hao;D. Sholl
中科院分区：
文献类型：
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作者：
Shiqiang Hao;D. Sholl
间隙氢的扩散在非晶态金属作为氢净化膜的潜在应用中起着关键作用。以非晶态Fe(3)B为例，我们展示了基于第一性原理的方法可以用来表征间隙氢在非晶态金属中的扩散。间隙氢的净输运是由菲克定律中的输运扩散系数决定的。这种扩散系数强烈地依赖于间隙浓度，并且除了稀疏间隙浓度外，不等于自扩散系数。在有实际意义的条件下，非晶态金属中间隙氢的浓度是非稀薄的，因此如果要描述净传质，必须使用确定传质扩散系数的方法。我们展示了如何使用第一性原理计算得到的H原子扩散速率的动力学蒙特卡罗模拟来评估H在非晶态金属中的自扩散系数和输运扩散系数。这些方法将有助于筛选非晶态金属合金作为氢气净化的潜在膜。
Diffusion of interstitial hydrogen plays a key role in potential uses for amorphous metals as membranes for hydrogen purification. We show how first principles-based methods can be used to characterize diffusion of interstitial H in amorphous metals using amorphous Fe(3)B as an example. Net transport of interstitial H is governed by the transport diffusion coefficient that appears in Fick's law. This diffusion coefficient is strongly dependent on the interstitial concentration, and is not equal to the self-diffusion coefficient except at dilute interstitial concentrations. Under conditions of practical interest, the concentrations of interstitial H in amorphous metals are nondilute so methods to determine the transport diffusion coefficient must be used if net mass transport is to be described. We show how kinetic Monte Carlo simulations of interstitial H diffusion that use rates derived from first-principles calculations can be used to assess both self- and transport diffusion coefficients of H in amorphous metals. These methods will be helpful in efforts to screen amorphous metal alloys as potential membranes for hydrogen purification.