Study on Diffusion of Hydrogen in AB5 Non-Stoichiometric Hydrogen Absorbing Alloys
来源期刊：JOURNAL OF RARE EARTHS2003年第6期
论文作者：彭文杰 王志兴 陈启元 李新海 郭华军
Key words：hydrogen absorbing alloy; diffusion; nonstoichiometry; electrochemistry;
Abstract: The diffusion coefficient of hydrogen atoms in the studied alloys was electroche mically measured by chronoamperometry when the metallic hydride microelectrodes were completely discharged. It is found that the diffusion coefficient of hydrogen atoms decreases when cobalt is substituted for a minority of nickel. On the contrary, the diffusion coefficient increases with the partial substitution of manganese or aluminum for nickel, which is related to the lattice constant and cell volumes of hydrogen absorbing alloys. The lattice constant c is obviously affected by the substitute elements greatly. The result shows that the expansion of cell volume resulted from the increase of value c causes the increase of diffusion coefficient which is especially obvious when the lattice constant is relatively low. However, this relationship is not clear if the lattice constant increases to some extent. It is suggested that this phenomenon is related to the interaction of hydrogen atoms with metallic atoms.
彭文杰1，王志兴1，陈启元1，李新海1，郭华军1
(1.Department of Metallurgical Physico-Chemistry, School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China)
Abstract:The diffusion coefficient of hydrogen atoms in the studied alloys was electroche mically measured by chronoamperometry when the metallic hydride microelectrodes were completely discharged. It is found that the diffusion coefficient of hydrogen atoms decreases when cobalt is substituted for a minority of nickel. On the contrary, the diffusion coefficient increases with the partial substitution of manganese or aluminum for nickel, which is related to the lattice constant and cell volumes of hydrogen absorbing alloys. The lattice constant c is obviously affected by the substitute elements greatly. The result shows that the expansion of cell volume resulted from the increase of value c causes the increase of diffusion coefficient which is especially obvious when the lattice constant is relatively low. However, this relationship is not clear if the lattice constant increases to some extent. It is suggested that this phenomenon is related to the interaction of hydrogen atoms with metallic atoms.
Key words:hydrogen absorbing alloy; diffusion; nonstoichiometry; electrochemistry;
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