Enhanced diffusion of Nb in Nb-H alloys by hydrogen-induced vacancies
Enhanced diffusion of Nb in Nb-H alloys by hydrogen-induced vacancies
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DOI：
10.1016/j.actamat.2005.02.049
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发表时间：
2005-06
期刊：
影响因子：
9.4
通讯作者：
T. Iida;Y. Yamazaki;Takayuki Kobayashi;Y. Iijima;Y. Fukai
中科院分区：
文献类型：
--
作者：
T. Iida;Y. Yamazaki;Takayuki Kobayashi;Y. Iijima;Y. Fukai
用连续溅射显微切片技术在823-1598K温度范围内测定了氢原子比H/Nb=0.05~0.34的纯Nb和Nb-H合金中95Nb的扩散系数。Nb在Nb-H合金中的扩散系数随氢浓度的增加而显著增大。讨论了扩散增强对温度和氢浓度的依赖关系，并用平均每个空位的氢原子占有数r进行了初步解释，认为扩散增强主要来自活化能Q的减小，这是由于r随氢浓度的增加而增大。指出了这一解释中存在的一些问题，以供今后研究之用。
The diffusion coefficient of95Nb in pure Nb and Nb–H alloys whose hydrogen concentration ranges between H/Nb=0.05 and 0.34 in atomic ratio has been determined in the temperature range 823–1598K using a serial sputter-microsectioning technique. The diffusion coefficient of Nb in the Nb–H alloys was found to increase significantly with increasing hydrogen concentration. The dependence of the diffusion enhancement on temperature and hydrogen concentration was examined in some detail, and explained tentatively in terms of average occupation number of hydrogen atoms per vacancy, r. The diffusion enhancement comes primarily from the decrease of the activation energy Q, resulting from the increase of r with increase of hydrogen concentration. Some remaining problems with this interpretation are pointed out for future investigations.