A Study on Guiding Principles to Predict the Properties of Hydrogen Absorbing Compounds with Emphasis on Their Positron Lifetime

以正电子寿命预测吸氢化合物性质的指导原则研究

• 批准号: 08555162
• 负责人: YAMAGUCHI Masaharu
• 金额: $ 12.42万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08555162/
• 关键词: Intermetallic compound; LaNi_5; Hydrogen absorbing; Positron annihilation; Positron lifetime; Deformability; Dislocation; Deformation modes; 金属問化合物; 状態図; 相平衡; 積層欠陥

Alloys based on the intermetallic phase, LaNi_5 (the hexagonal CaCu_5-type structure) have been used as negative electrode materials of rechargeable nickel-metal hydride batteries. In order to develop rechargeable nickel-metal hydride batteries with higher performance than that of batteries using LaNi_5 as their negative electrode materials, a new intermetallic compound with a higher hydrogen storage capacity than that of LaNi_5 with reasonable resistance to powdering after cycles of hydriding-dehydriding is required to be discovered.The stabilities of metal hydrides are closely associated with the radii of interstitial holes in their lattices and the valence of constituent elements. Positron life time is sensitive to both the radii of interstitial holes and valence of constituent elements. One of the two aims of this study is to study the correlation between hydrogen desorption pressure and positron life time and that between unit cell volume and positron lifetime. The other aim is to … More clarify the deformation modes in LaNi_5 as basic knowledge to control the powdering of the compound.Measurements of positron life time in LaNi_5, LaNi_<5-X>Al_X and MmNi_<5-X>Al_X results in the following findings : (1) no structural vacancies exist in LaNi_5 and thus hydrogen atoms trapped at interstitial holes, (2) the positron lifetime in LaNi_<5-X>Al_X and MmNi_<5-X>Al_X is proportional to the size of their unit cell, (3) the plateau pressure of LaNi_<5-X>Al_X and MmNi_<5-X>Al_X is proportional to the positron lifetime in these compounds, (4) thus, positron lifetime measurements can be used to develop new hydrogen absorbing compounds.Deformation experiments of LaNi_5 at high temperatures result in the following findings : (1) LaNi_5 can be deformed at temperatures higher than 950ﾟC,(2) yield stress rapidly decreases with increasing temperature, (3) dislocations with Burgers vectors of [0001] and 1/3 <1120> are observed in specimens deformed at temperatures higher than 950ﾟC,(4)slip plane for the former type of dislocations is {1010}. However, that for the latter type of dislocations has yet to be determined. Less

以六方CaCu_5型结构的金属间化合物LaNi_5为基础的合金已被用作可充电镍氢电池的负极材料。为了开发性能优于LaNi_5负极材料的镍氢电池，一种新的金属间化合物，具有比LaNi_5更高的储氢容量，并具有合理的抗粉化性能，金属氧化物的稳定性与其晶格中间隙孔的半径以及晶格中的氢原子的数量密切相关。组成元素的化合价。正电子寿命对填隙孔的半径和组成元素的化合价都很敏感。本研究的两个主要目的之一是研究氢脱附压力与正电子寿命的关系以及单胞体积与正电子寿命的关系。另一个目标是 ...更多信息 LaNi_5、LaNi_<5-X>Al_X和MmNi_<5-X>Al_X的正电子寿命测量结果表明：（1）LaNi_5中不存在结构空位，因此氢原子被捕获在间隙空穴中;（2）LaNi_<5-X>Al_X和MmNi_<5-X>Al_X的正电子寿命与其晶胞尺寸成正比;（3）LaNi_<5-X>Al_X和MmNi_<5-X>Al_X的平台压力与正电子寿命成正比;（4）因此，LaNi_5的高温形变实验结果表明：（1）LaNi_5在高于950 ℃的温度下可以发生形变，（2）屈服应力随温度的升高而迅速降低，（3）在高于950 ℃的温度下形变的样品中观察到Burgers矢量为[0001]和1/3的位错<1120>，（4）前者的滑移面为{1010}。然而，对于后一种类型的位错，尚未确定。少

项目成果

M.Yamaguchi et al: "C-type dislocations emitted from cracks introduced in a thin fail of LaNi_5" J.Alloys and Compound. (in press). (1998)

M.Yamaguchi 等人：“LaNi_5 薄层失效中引入的裂纹发出的 C 型位错”J.合金与化合物。

山口正治: "材料システム学 -力学的性質の統一的理解のために- 第3章ミクロ構造" 共立出版, 1600 (1997)

Masaharu Yamaguchi：“材料系统 - 为了统一理解机械性能 - 第 3 章微观结构”Kyoritsu Shuppan，1600 (1997)

M.Yamaguchi et al.: "Vacancies and their clusters in MoSi_2 studied by positron life time spectrometry" Intermetallics. (in press). (1998)

M.Yamaguchi 等人：“通过正电子寿命光谱法研究 MoSi_2 中的空位及其簇”金属间化合物。

M.Yamaguchi et al.: "Microstructures and defect structures in La-Ni alloys" J.Alloys and Compound. (発表予定).

M. Yamaguchi 等人：“La-Ni 合金中的微观结构和缺陷结构”J.合金与化合物（待出版）。

M.Yamaguchi et al.: "Physical Metallurgy and Processing of Intermetallic Compounds,Chapter 1 Defect Structures pp.3-27" Chapman & Hall, 684 (1996)

M.Yamaguchi 等人：“金属间化合物的物理冶金和加工，第 1 章缺陷结构 pp.3-27” Chapman