特种工艺方法制备储氢合金评述

首先分别简述了气体雾化法、熔体快淬法和铸带法制备储氢合金的微观组织结构特征和电化学性能。其次从合金电极充—放电机理出发分析了具有易活化、高容量、长寿命及高倍率性能等优异电化学性能的储氢合金应该具有的理想微观组织特征。说明了气体雾化法和快淬法在储氧合金制备中固有的弊端，指出铸带法是3种特种工艺方法中制备高性能AB5型储氢合金的最佳选择。     

Electrochemical Properties of Strip Casting LPCNi3.55Co0.75Mn0.4Al0.3 Hydrogen Storage Alloys

LPCNi3.55Co0.75Mn0.4Al0.3 hydrogen storage alloy was investigated, and the effects of thickness of its strip casting ingots(as-cast) on the electrochemical performances were discussed. It was found that the 0.2 C discharge capacity increased with the increase of the thickness (from 1 mm to 10 mm) of the ingots, mainly due to the enlargement of the unit cell volume; Among the thickness of the ingots in our study, l0 mm sample showed a better activation property; LPCNi3.55Co0.75Mn0.4Al0.3 alloy with 10mm showed higher comprehensive properties than those with other thickness under 1C rate.     

Effect of Annealing on Rare Earth Based Hydrogen Storage Alloys

Rare earth-based hydrogen storage alloy used as negative electrode materials for nickel-metal hydride (Ni-MH) batteries are used commercially.The effect of annealing treatment with different annealing temperature and time on the MLNi3.68 Co0.78 Mn0.35 Al0.27 and MMNi3.55 Co0.75 Mn0.40 Al0.30 alloys were investigated.The crystal microstructure,pressure-composition-isotherms (p-C-T) and electrochemical properties of alloys were examined by X-ray diffraction (XRD), automatic PCI monitoring system and electrical performance testing instruments.The optimum annealing treatment conditions of two kinds of alloys were determined.     

镍氢电池负极用纳米晶稀土贮氢合金的性能研究

对采用双辊快淬法制备的纳米晶稀土贮氢合金Ml(NiCoMnAl) 5相结构、贮氢性能和电化学充放电性能进行了研究分析。X射线衍射分析 (XRD)结果表明 ,合金片由均匀的CaCu5相组成 ,其晶粒尺寸平均为 2 0～ 40nm。PCT测试表明 ,该合金具有很好的平台特性和较小的滞后效应。将合金粉压成极片组装成模拟电池以 3 0 0mA·g- 1 (1C)电流充电 ,分别以 2 0 0 0mA·g- 1 (7C)和 3 0 0 0mA·g- 1 (10C)电流放电至 0 .9V和 0 .8V ,其电化学容量分别达到 2 5 0和 2 3 0mAh·g - 1。在 7C放电情况下 ,经 45 0循环后 ,容量衰减率小于 2 0 %。     

Development of Strip Casting Technology in Rare Earth Permanent Magnet Alloys and Hydrogen Storage Alloys in China

The SC technique is now being applied widely in material preparation, especially in rare earth functional materials in virtue of its advanced process and high performance product. The applications of SC technique in rare earth permanent magnet alloys and hydrogen storage alloys were analyzed integrative, on the basis of summary of SC technique development in this paper. The paper mainly includes development history of SC technology, effect of SC technology on alloy microstructure, application of SC technology in RE storage hydrogen alloy and sintered Nd-Fe-B alloy, development of SC equipment and SC product industry. At the same time, the paper points out the existing problem of SC products.     

Study on Kinetics of Hydrogen Absorption by Metal Hydride Slurries Ⅰ. Absorption of Hydrogen by Hydrogen Storage Alloy MlNi_5 Suspended in Benzene

Ｈｙｄｒｏｇｅｎｓｔｏｒａｇｅａｌｌｏｙｈａｖｅａｔｔｒａｃｔｅｄｍｕｃｈａｔｔｅｎｔｉｏｎｂｅｃａｕｓｅｏｆｔｈｅｉｒｌａｒｇｅｃａｐａｃｉｔｙｆｏｒｈｙｄｒｏｇｅｎｓｔｏｒａｇｅｃｏｕｐｌｅｄｗｉｔｈｔｈｅｉｒｒｅａｄｙｒｅｌｅａｓｅｏｆｈｙｄｒｏｇｅｎａｔｍｏｄｅｒａｔｅｔｅｍｐｅｒａｔｕｒｅｓａｎｄｐｒｅｓｓｕｒｅｓａｎｄｔｈｅｉｒａｂｉｌｉｔｙｔｏｕｎｄｅｒｇｏｍａｎｙｃｙｃｌｅｓｏｆａｂｓｏｒｐｔｉｏｎａｎｄｄｅｓｏｒｐｔｉｏｎｗｉｔｈｌｉｔｔｌｅｄｅｃｒｅａｓｅｉｎｃａｐａｃｉｔｙ…     

Effects of Strip Casting and Annealing on Electrochemical Properties of LPCNi3.55Co0.75Mn0.4Al0.3 Hydrogen Storage Alloys

The effect of thickness (1～10 mm) of the ingots on the electrochemical properties of as-cast and annealed strip cast LPCNi3.55Co0.75Mn0.4Al0.3 hydrogen storage alloys was investigated. It is found that the 0.2 C discharge capacity of as-cast LPCNi3.55Co0.75Mn0.4Al0.3 alloy increases with the increase of the thickness of the ingots. As-cast alloy with the thickness of 10 nun shows better activation property, higher 1C discharge capacity and better cyclic stability than others.It is mainly contributed to its larger unit cell volume and less internal stress. Annealed LPCNi3.55Co0.75Mn0.4Al0.3 alloywith the thickness of 3 mm shows much better comprehensive electrochemical properties than as-cast one; The cyclic stability of the alloy with the thickness of 6 mm and the activation properties of the alloys with the thickness of 3～6 mm are improved after annealing. It is mainly owing to the great release of intemal stress and the decrease fo the segregation of Mn in the alloys.     

Kinetics of Liquid-Phase Hydrogenation of Toluene Catalyzed by Hydrogen Storage Alloy MlNi_5

Asacleanandhigh efficiencyenergyresource ,hydrogenisthoughttobethemostpromisingsubstituteoffossilfuels .Storingandutilizingtheenergybyus ingthehydrogenasenergycarrieristhemostfavor ablemethodtosolvetheenergycrisis ,whichattractsthefocusoftheworld .Therehavebeenconsiderableprogressesinthetechnologyofhydrogen energyinre centyears .Reillyetal .[1] firstproposedtheconceptofthemetalhydrideslurryin 1 980s ,inwhichthede formationorruptureofthevesselsduetotheparticlepulverizationandthepoorheattransfer…     

贮氢合金进展

对贮氢合金的工作原理及应用,贮氢合金的基本类型及开发历史和发展趋势进行了综合评述。MmNi5系稀土合金和Laves相合金的开发应用已较为成熟,但其贮氢密度不高,高容量型的钒固溶体型合金和镁基合金是贮氢合金发展的新趋势。目前主要通过添加合金元素、开发制备工艺,改进微观相组织结构并兼以适当的表面处理,以提高钒固溶体型合金和镁基合金常温常压下的吸放氢特性及活化性能。     

多元低钴稀土基贮氢合金及其电极特性

本文根据多元合金化原则设计了一系列电极用低钴 AB5型贮氢合金。并对其组织、不同温度和不同倍率的电化学性能、P- C- T特性进行了研究。结果表明 ,用多元合金化降低 Co含量后 ,合金的放电容量虽有不同程度的降低 ,但可明显改善其充放电循环稳定性 ,且各种合金在 2 0℃时 1 C和 0 .2 C的放电比率、0 .2 C充放电时 40℃和2 0℃的放电比率均基本保持不变。低 Co合金具有更低的平台压。     

Characteristic Investigation of Nano-Crystal Hydrogen Storage Alloys

A Ml (NiCoMnA1)5 hydrogen storage alloys was prepared by double-roller rapid quenching.Its microstructure, electrochemically and kinetic characteristic were studied.A uniform crystal phase with CaCu5 structure could be detected by XRD analyses, whose average grain size is 30 ～ 50 nm and the ratio of c/a of nano-crystal hydrogen storage alloy is larger.The hydrogen absorption/desertion p - C isotherms of alloy show that its fiat-performance is perfect and the magnetic stagnant effect is very little.An simulate cell is used for electrochemical measurement.Electrode is 10C, the capacity decreasing rate via the 450 cycles at 7C is less than 20%.     

贮氢合金的表面处理

本文根据国内外关于贮氢合金表面性质对其电化学性能影响的研究结果,综述了近年来贮氢合金表面改性处理的现状和进展     

氢化燃烧法合成镁基储氢合金进展

以Mg2 Ni为例系统综述了氢化燃烧法制备镁基储氢合金的进展 ,包括其工作原理 ,氢化燃烧法和其它制备镁基储氢合金方法的比较 ,影响氢化燃烧的因素以及材料的氢化特性。较为详细地介绍了国内外的研究状况并进行比较 ,通过比较Mg2 Ni、Mg2 FeH6 、Mg2 CoH5等储氢合金的吸氢性能 ,指出制备镁基储氢合金的理想发展方向应该是采用复合方法获得实用产品 ,即结合氢化燃烧 ,机械合金化 ,多元化 ,纳米化等方法 ,制备非晶态合金 ,以期达到低温下吸放氢量大于 5 %(质量分数 ) ,具有良好的动力学性能 ,使用寿命长 ,低价格的效果。     

Investigation of Coercivity Mechanism for Nd-Fe-B Magnets Prepared by Combination of Strip-Casting with Hydrogen Decrepitation Techniques

The coercivity mechanism of Nd-Fe-B magnets prepared by combination of strip-casting with hydrogen decrepi-tation techniques was investigated. The microstructure of (Nd0.935Dy0.065)14.5Fe79.4B6.1 magnet was observed. The average grain size is about 6 ～ 12 μm. The magnetizing field dependence of the hardmagnetic properties for the (Nd0.935Dy0.065)14.5 Fe79.4B6.1 and the temperature dependence of the coercivity for the Nd14.5Fe79.4B6.1 were investigated. Results show that the coereivity for magnets prepared by the combination of strip-casting with hydrogen decrepitation techniques is controlled by the nucleation mechanism.     

V-Ni二元合金的吸放氢性能

研究了V100-xNix（x=0～12％（原子分数））二元合金的活化性能、吸氢动力学性能、放氢PCT性能及吸放氢过程相结构的变化。Ni的添加提高了钒的活化性能和动力学性能。随着Ni含量的增加，γ相的分解压逐渐升高，稳定性降低。在20℃，3MPa氢压下，当Ni含量高于0．5％（原子分数）时，γ相的含量迅速降低，饱和吸氢量明显减少，当Ni含量超过2％（原子分数）时，γ相消失。增加Ni含量，有利于降低B相的含量，提高B相的分解压。随着Ni含量的增加，合金的晶格常数呈线性趋势降低。     

Electrochemical Properties of Silicon Doped MlNi5 Type of Hydrogen Storage Alloys

ＴｈｅＬａＮｉ5 ｂａｓｅｄｈｙｄｒｏｇｅｎｓｔｏｒａｇｅａｌｌｏｙｓａｒｅｐｒｏｍｉｓｉｎｇｎｅｇａｔｉｖｅｅｌｅｃｔｒｏｄｅｍａｔｅｒｉａｌｓｆｏｒｒｅｃｈａｒｇｅａｂｌｅＮｉ/ＭＨｂａｔｔｅｒｉｅｓｂｅｃａｕｓｅｔｈｅｙｐｏｓｓｅｓｓａｈｉｇｈｃａｐａｃｉｔｙａｎｄａｒｅｅａｓｙｔｏａｃｔｉ ｖａｔｅ .ＢｕｔｔｈｅｄｉｓｃｈａｒｇｅｃａｐａｃｉｔｙｏｆｔｈｅＬａＮｉ5ｅｌｅｃｔｒｏｄｅｄｅｃｌｉｎｅｓｒａｐｉｄｌｙｄｕｒｉｎｇｃｈａｒｇｅ ｄｉｓ ｃｈａｒｇｅｃｙｃｌｅｓ (5 0 %ｏｆｔｈｅｃａｐａ…     

Crystallization and Microstructure Evolution of Amorphous Al85 Y4 Nd4 Fe7 Alloy

A rapidly solidified Al85Y4Nd4Fe7(%, in nominal atomic fraction) alloy was prepared by melt spinning. Asquenched and as-annealed microstructures were studied by differential scanning calorimetry (DSC), X-ray diffraction(XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Fully amorphous structure could be obtained in the rapidly solidified Al85Y4Nd4Fe7 alloy ribbons. The temperature of first crystallization exceeds 300℃. Crystallization of as-annealed Al85Y4Nd4Fe7 alloy is shown to occur in two stages : ( 1 ) primary crystallization of α-Al; (2) formation of Al3Y, Al13Fe4 and unknown crystalline phases.     

CO毒化AB5型合金分形特征研究

研究了三种贮氢合金 L a Ni5、L a Ni4 .7Al0 .3、Ml Ni4 .5Al0 .5被 10 0× 10 - 6 CO毒化后的分形特征 ,求出这三种合金在含 10 0× 10 - 6 CO的氢中循环 ,分维分别为 0 .2 5 4 7、0 .170 9、0 .0 72 5。可以较好的解释合金被毒化的宏观现象。     

Phase Structure and Electrochemical Properties of RE-Mg Based Composite Hydrogen Storage Alloys

Rareearth basedAB5 typealloy ,akindofhy drogenstoragealloyusedasnegativeelectrodemateri alsofthenickel/metalhydride (Ni/MH )secondarybattery ,haseasyinitialactivation ,longcyclelifeandlowcost ,butstillasmalldischargecapacity ,poorhigh ratedischargeability(HRD)andpoorpropertiesatlowtemperature[1,2 ] .Therefore ,howtoincreaseitsdischargecapacityandtoimproveotherelectrochemi calpropertiesismeaningfulbothintheoryandinpracticalapplication .Mg basedhydrogenstorageal loysareremarkablebecauseofitsr…     

Study on High Rate Discharge Performance and Mechanism of AB5 Type Hydrogen Storage Alloys

The effects of surface treatment, particle size distribution, rare earth composition and B additive on the high rate discharge performance of hydrogen storage alloys were investigated. It is found that the activity, discharge capacity and high rate dischargeability of the alloys are improved after physical and chemical modification as a result of the increase of the surface area and formation of the electrocatalysis layers, which increase both the electrochemical reaction rate on the alloy surface and H diffusion rate in the alloy bulk. It is also found that both the over-coarse and over-fine particle size increase the contact resistance of the electrode, resulting in a decrease of discharge capacity, deterioration of high rate dischargeability and lower discharge plateau. In another word, a suitable particle size distribution can enhance the alloy activity, discharge capacity and high rate dischargeability. In addition, the high rate dischargeability is enhanced by in-creasing La content and decreasing Ce content of the alloy composition because of enlargement of the unit cell volume and the improvement of the surface activity. Moreover, B additive resultes in the formation of the second phase, and makes the alloys easier pulverization, which greatly improves the activity, discharge capacity and high rate dischargeability.