Hydrogen-diffusion in Pd1−xAgx (0⩽x⩽1)
Hydrogen-diffusion in Pd1−xAgx (0⩽x⩽1)
复制标题
Pd1−xAgx (0⩽x⩽1) 中的氢扩散
DOI：
10.1016/s0925-8388(96)02970-2
复制
发表时间：
1997
影响因子：
6.2
通讯作者：
Harald Züchner
中科院分区：
文献类型：
--
作者：
L. Opara;B. Klein;Harald Züchner
通过进一步改进电化学脉冲时间滞后技术，现在可以测量在PdAg合金系列的富银侧上的氢扩散系数，尽管氢在纯银和富银合金中的溶解度极低。测得的宏观扩散系数的氢在银达到的值相当于纯Pd中的扩散，但由数量级，高于在Pd0.5Ag0.5合金。为了描述这一扩散过程已被视为理论上从微观的观点。该过程已经通过计算机计算模拟，假设氢作为Pd基质（具有高氢溶解度）中的随机步行者，其中银统计地分布，由于极小的氢溶解度而在很大程度上阻挡氢扩散路径。计算的均方距离显示出与所测量的宏观扩散系数一样的随银含量增加的类似行为。这意味着通过PdAg合金的氢扩散优选地经由避开富Ag区域的“富Pd扩散路径”以迂回方式发生。
By further improvement of the electrochemical pulse time-lag technique it has now become possible to measure the hydrogen diffusion coefficient on the silver rich side of the series of PdAg-alloys, despite the extremely low hydrogen solubility in pure silver and the silver rich alloys. The measured macroscopic diffusion coefficient of hydrogen in Ag reaches values comparable to the diffusion in pure Pd, but is, by orders of magnitude, higher than in the Pd0.5Ag0.5alloy. In order to describe this the diffusion process has been regarded theoretically from a microscopical point of view. This process has been simulated by computer calculations assuming hydrogen as a random walker in a Pd matrix (with high hydrogen solubility) where silver is distributed statistically, blocking the hydrogen diffusion paths to a great extent due to the extremely small hydrogen solubility. The calculated mean square distance shows an analogous behavior with increasing silver content as the measured macroscopic diffusion coefficient. This means that hydrogen diffusion through PdAg alloys takes place preferably by a roundabout way via “Pd-rich diffusion paths” avoiding Ag-rich regions.