赵炳建鲁雄刚李重河钟庆东
金属学报
在CaCl2熔盐中, 利用固体透氧膜(SOM)法直接电解混合氧化物NiO-CeO2制备CeNi5合金, 并与熔盐电解法(FFC)进行了对比. 阴极的制作方法与FFC法相同, 阳极为碳饱和Cu(或Sn) 液, 采用只允许氧离子通过的透氧膜隔开阴极和阳极, 这样可以采用较高的电解电压 (3.5 V)以获取更高的电解速率. 研究了SOM法制备CeNi5合金的可行性和影响因素, 如电解温度、电解时间, 以及产物的相组成和形 貌等. 结果表明: 通过SOM法, NiO-CeO2可完全还原为CeNi5. 电解中间产物的相组成分析表明, CeNi5的形成过程为: NiO首先还原为 Ni, 与随后生成的CeOCl反应生成CeNi5. SOM法与FFC法对比表明, 2.5 g的烧结试样采用SOM法电解3 h可电解完全, 电流效率为75.5%, 能耗为4.03 kW•h/kg; 采用FFC法需12 h才能电解出纯的CeNi5合金, 其电流效率为26.1%, 能耗为10.27 kW•h/kg. 相比于FFC法, SOM法具有更好的工业化应用前景.
关键词:
透氧膜
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electrolysis
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CeNi5
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hydrogen storage alloy
M.Morinaga and H. Yukawa Department of Materials Science and Engineering
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Graduate School of Engineering
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Nagoya University
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Furo-cho
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Chikusa-ku
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Nagoya 464-8603
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Japan
金属学报(英文版)
The electronic structures are calculated by the DV-Xa molecular orbital method employing small model clusters in order to clarify the roles of the hydride forming elements, A, (e.g., La, Zr Ti, Mg) and non-forming elements, B, (e.g., Ni, Mn, Fe) in hydrogen storage alloys. It is confirmed from this calculation that hydrogen interacts more strongly with hydride non-forming elements, B, than hydride forming elements, A, in agreement with our previous calculations. However,the B-H interaction is enhanced only when some A element exists in the neighborhood. Otherwise, such a B-H interaction never operates in the alloy. In this sense,the coexistence of A and B elements are essential in the constitution of hydrogen storage alloys. Also, it is shown that the A/B compositional ratio of hydrogen storage alloys is understood in terms of a simple parameter, 2Bo(A - B) / /Bo(A - A)+ Bo(B-B)], where the Bo(A-B), Bo(A-A) and the Bo(B-B) are the bond strengths between atoms given in the parentheses.
关键词:
electronic structure
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null
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null
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null
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null
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null
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null
黄火根
,
陈亮
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杜晓清
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李嵘
稀有金属材料与工程
Ti-Zr-Ni基二十面体准晶是一类特殊的储氢材料,在氢能和核聚变能领域具有较强应用前景.采用XRD、TEM、XPS技术和气固反应系统研究了Ti39Zr38Ni17Pd6二十面体准晶的储氘性能.该合金室温下的饱和吸氘浓度接近11 mmol·D2/g·M (D2指氘分子,M指金属),超过Zr2Fe和ZrCo 2种合金.在吸放氘循环过程中,没有发现该合金发生相转变.饱和吸氘使得准晶格膨胀了6.37％,并使得Ti与Zr的结合能上升0.2和0.6 eV,反映出氢原子在这种材料中的占位更靠近这2种金属原子.放氘结果显示该合金具有可能较低的坪台压力,350℃左右低于1 kPa,这意味着氘原子在该合金中比在ZrCo合金中具有更高的稳定性.以上结果表明,这种准晶有可能替代Zr2Fe和ZrCo合金而在核聚变能领域得到应用.
关键词:
准晶
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储氢合金
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氢同位素
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Ti-Zr-Ni-Pd
X.G
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Yang
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Q.A. Zhang
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K. Y Shu
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YL. Du
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YQ. Lei and Q.D. Wang (Department of Materials Science and Engineering
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Zhejiang University
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Hangzhou 310027
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China )W.K. Zhang(Department of Applied Chemistry
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Zhejiang University of Technology
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Hangzhou 3100l4
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China )G.L. Lu(Central Lab
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Zhejiang University
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Hangzhou 310028
,
China)
金属学报(英文版)
The annealing treatment was found to improve the cyclic stability but to degmde discharpe capacity, activation and high-rate discharpeability for the Ti-substituted AB2type alloy electrode. A larper polarization was found in the annealed alloy because of its poor discharpe kinetics resulted hem the structural homogeneity. At larae discharpe cumnts, the hydmpen dchsion in the bulk of the alloy was mpaofed as the mte-determining step. Based on the P ressure-composition isotherm measurement, we concluded that the decrease in discharpeability of the annealed alloy is owing to the low and flat pressure plateau, as well as the large hysteresis, but the hydrgen stomge density almost remains unchangeable after annealing.
关键词:
AB_2
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null
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null
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X.H. Wang(Department of Materials Science and Engineering
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Zhejiang University
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Hangzhou 310027
,
China)
金属学报(英文版)
In this paper, a mathematical model for the stability of hydrides of Ca containing compounds was proposed on the basis of introducing the geometrical and electric factors. The data on (R, Ca)Ni5 compounds are in good agreement with the theoretical curve obtained from the model. For Ml1-x CaxNi5 compounds, the variation of dissociation pressure with cell volume is the joint effects of geometrical and electric factors, and the controlling factor changes gradually from geometrical factor to electric factor with increasing x.
关键词:
hydride
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null
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null
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