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.     

高倍率AB5型稀土贮氢合金的研究进展

综述了AB5型稀土贮氢合金高倍率放电性能的影响因素。从合金成分、制备工艺、粒度控制以及表面改性等几个方面进行总结，并对贮氢合金高倍率放电机制等问题进行了讨论。开发低钴无钴系列合金、非化学计量比、形成双相合金、控制粒度分布以及表面改性处理是目前改善AB5型稀土贮氢合金高倍率放电性能的有效途径。     

Preferential Oxidation of CO in H2 over CuO／CeO2 Catalysts

Over the past few years, the design and researchon fuel cells have been made a great development. Avariety of fuel cells for different applications has beenunder development[1,2]: solid polymer fuel cells(SPFC), also know as proton exchange …     

稀土基AB5型复合贮氢合金的研究进展

制备复合合金是改善贮氢合金性能的一条有效途径。本文对国内外各种多元以及多相稀土复合贮氢材料的研究现状进行了综合评述，主要涉及了AB5-AB2型复合贮氢合金和镁基-AB5型纳米复合贮氢合金的进展。阐述了各种复合材料的组成，微观结构以及电化学性能等，并展望了今后复合贮氢材料的研究方向为应用基础性的研究，如复合作用机制、对热力学性能的影响等方面的研究。     

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 %。     

Status of Research on Application of High Purity Rare Earth Oxides in Solid Oxide Fuel Cells

The solid oxide fuel cell (SOFC) is a high-efficient and environmentally friendly power generation system.The rare earth oxide materials are used extensively in the manufacturing of SOFC components.In particular, the CeO2doped with Gd2O3 or Sm2O3, lanthanide perovskite oxides are indispensable and key materials for developing the intermediate temperature SOFC.The research and development status of application of high purity rare earth oxides in SOFC was overviewed.The rare earth oxide-based and -doped materials were discussed for the SOFC components.Concerning the rare earth oxides applicable to SOFC, several topics were also pointed out for further researching and developing.     

Synthesis of PET and Its Copolymer with Rare Earth Catalysts

A new catalyst system was used in the synthesis of polyethylene terephthalate(PET) and its copolymers, which involved a Ln3 containing compound. The catalytic effects were studied, and it was found that the direct esterification reaction of terephthalate acid(TPA) with ethylene glycol (EG) can be accelerated by the addition of Ln3 ~ containing compound, which acts as a promoter of the catalyst Sb203 in polycondensation of bis hydroxyethyl terephthalate(BHET).     

Oxides Catalysts of Rare Earth and Transient Metal for Catalytic Oxidation of Benzene

The catalysts of CeO2 and the mixture of CeO2 and CuO were prepared, and the activities of these catalysts for completely oxidizing benzene were studied.The results show that the optimal proportion of CeO2/CuO is 6: 4.The highest temperature at which benzene was completely oxidized on these catalysts at different airspeed was measured.Compared these catalysts with the noble metal used, our catalysts had superiority in the resources and the industrial cost besides good activities.     

Hydrogen Absorption of Nd-Fe-B Alloys

The technical parameters of HD process were studied, including the effects of temperature and neodymium contents on the incubation period of hydrogen absorption, hydrogen concentration and the rate of hydrogen absorbed. The results show that the incubation period is shortened and the rate of hydrogen absorbed is accelerated with rising temperature and surface area. These are attributed to the rising rate of hydrogen diffusion at higher temperature. The change of the incubation period and the rate of hydrogen absorbed have the similar trend resulted from the increasing content of the Nd-rich phase owing to the rising temperature. Moreover, the percent of the Nd-rich phase in the ingot can be calculated according to the total hydrogen weight gain.     

Hydrogen Absorption Thermodynamic Properties of Rare-Earth Based Hydrogen Storage Alloy in Benzene

Ｔｈｅｐｒｏｐｅｒｔｙｔｈａｔｔｈｅｒａｒｅｅａｒｔｈｂａｓｅｄｈｙ ｄｒｏｇｅｎｓｔｏｒａｇｅａｌｌｏｙｓｃａｎａｂｓｏｒｂ/ｄｅｓｏｒｂａｌａｒｇｅａｍｏｕｎｔｏｆｈｙｄｒｏｇｅｎａｔｒｏｏｍｔｅｍｐｅｒａｔｕｒｅｈａｓｂｅｅｎｕｓｅｄｓｕｃｃｅｓｓｆｕｌｌｙｆｏｒｈｙｄｒｏｇｅｎｓｅｐａｒａ ｔｉｏｎ ,ｐｕｒｉｆｉｃａｔｉｏｎ ,ａｎｄｔｒａｎｓｐｏｒｔａｔｉｏｎ .Ｉｎｔｈｅａｐｐｌｉｃａｔｉｏｎｓ ,ｉｎｏｒｄｅｒｔｏａｖｏｉｄｐｒｏｂｌｅｍｓｓｕｃｈａｓｔｈｅｏｂｓｔｒｕｃｔｉｏｎｔｏｇａｓ…     

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。     

Hydrogen Absorption and Release Behavior in Hydrogen Decrepitation Process of Nd-Fe-B Alloys

The behavior of hydrogen absorption and release in hydrogen decrepitation (HD) process of Nd-Fe-B alloys were investigated. The results reveal that the reactivity and the amount of hydrogen absorption in HD process are related to the surface activity of the alloy so that the fresh and active surface has a higher efficiency. The presence of Nd-rich phase at the grain boundary is an essential factor of the HD activity of the alloy at room temperature. On degassing, hydrogen is released from the HD powder continuously with increasing temperature. And the residual hydrogen is as low as 0.0015% at 1073K, which shows that the hydrogen is almost exhaused. It is feasible to remove the hydrogen from the HD powder by heating treatment at the temperature of 523-723K for 1h prior to the magnetic field forming in order to decrease the harmful effect of hydrogen on the easy axis alignment of HD magnet.     

Preferential Oxidation of Carbon Monoxide in Excess Hydrogen over Au/Co3O4-CeO2 Catalysts

Fuel cells are considered to be the propulsionsystem of the near future,since they can produceelectricity without pollutingthe environment,and pos-sess the necessary specific power,power density anddurability to replace conventional internal combustioneng…     

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

Ｈｙｄｒｏｇｅｎｓｔｏｒａｇｅａｌｌｏｙｈａｖｅａｔｔｒａｃｔｅｄｍｕｃｈａｔｔｅｎｔｉｏｎｂｅｃａｕｓｅｏｆｔｈｅｉｒｌａｒｇｅｃａｐａｃｉｔｙｆｏｒｈｙｄｒｏｇｅｎｓｔｏｒａｇｅｃｏｕｐｌｅｄｗｉｔｈｔｈｅｉｒｒｅａｄｙｒｅｌｅａｓｅｏｆｈｙｄｒｏｇｅｎａｔｍｏｄｅｒａｔｅｔｅｍｐｅｒａｔｕｒｅｓａｎｄｐｒｅｓｓｕｒｅｓａｎｄｔｈｅｉｒａｂｉｌｉｔｙｔｏｕｎｄｅｒｇｏｍａｎｙｃｙｃｌｅｓｏｆａｂｓｏｒｐｔｉｏｎａｎｄｄｅｓｏｒｐｔｉｏｎｗｉｔｈｌｉｔｔｌｅｄｅｃｒｅａｓｅｉｎｃａｐａｃｉｔｙ…     

Application of Rare Earth Oxides in Diesel Exhaust Purification Catalysts

Diesel oxide catalysts and soot combustion catalysts were reported in this paper.The former was manufactured in mass last year, and enhanced performance is under development now.The later is screened out and further research is under way.The best soot combustion catalyst could ignite soot combustion even at 350 ℃, which is within the range of temperatures reached in diesel exhaust, and shows the catalytic combustion velocity nearly one time faster compared with non-catalytic combustion of soot, which is of benefit to rapid regeneration of diesel particulate filter, thus it might be an excellent practicable catalyst.     

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.     

Evolution of Hydrogen Storage Alloys Prepared by Special Methods

Microstructure characteristics and electrochemical properties of hydrogen storage alloys prepared by gas atomization, melt spinning and strip casting respectively were outlined.The advantages, disadvantages and research development of the above methods for preparing hydrogen storage alloys were explained.The strip casting is a new special means for preparing AB5 rare earth hydrogen storage alloys of high performance and low cost, and the study of the strip casting for preparing hydrogen storage alloys is presented specially.     

RE-Mg-Ni系储氢合金高倍率放电性能研究现状

RE-Mg-Ni系储氢合金具有超晶格结构,其主相晶格单元是由一定比率的AB5单元和AB2单元沿c轴交替层叠排列而成。该类型合金自问世以来便以其高容量、易活化的优势受到人们的广泛关注,然而其循环稳定性及高倍率放电性能不尽人意。人们通过大量研究有效提高了其循环稳定性,使其基本满足了商业化要求。但是要将基于该负极材料的镍氢电池应用在混合动力汽车上,仍需改进其高倍率放电性能。系统分析了元素替代、多元合金化、制备工艺、化合物复合、表面处理等手段对RE-Mg-Ni系储氢合金晶体结构及高倍率放电性能的影响。其中元素替代是一种重要且有效的手段,文中分析了不同稀土元素及B侧元素的作用机制,结果表明,B侧组分采用Ni,Co,Mn,Al的储氢合金具有较好的性能。多元合金化是一种复杂的过程,不同元素间可能存在一定的协同作用,研究其作用机制也是下一步的工作重点。通过优化实验方案,综合使用多种改性手段,可以得到高倍率放电性能良好的RE-Mg-Ni系储氢合金,使其基本满足电动工具用镍氢电池的要求,并可望在以后的研究中进一步提高其高倍率放电性能,使其满足混合动力汽车用镍氢电池的要求,实现良好的经济和社会效益。     

Synthesis, Characterization and Fluorescence of Rare earth Nitrate Complexes with Triaza-crown Ether Derivative

Sinceaza crownethershowsspecialcoordinationpropertiestotransitionmetalandheavymetalions[1,2 ] ,therearemanyreportsofthecomplexesinhost guestchemistry ,molecularrecognition[3 ,4] andionophoreinmembranetransportation[5] ,butthereislittlereportontheirrareearthscomplexesandthefluorescenceaboutthecomplexes[6] ,andthefluorescenceintensityoftheircomplexesarenotverystrong .Weinsetbenzoylgroupintothemacrocycle ,expectingthatitsrareearthscomplexeshavebetterfluorescenceproperties .Inthispaperthesynthesis…     

Study on Kinetics of Hydrogen Absorption by Metal Hydride Slurries Ⅱ. Hydrogenation of Benzene Catalyzed by MlNi_5

Ｂｅｎｚｅｎｅｈｙｄｒｏｇｅｎａｔｉｏｎｉｓｏｆｉｎｄｕｓｔｒｉａｌｉｍ ｐｏｒｔａｎｃｅｂｅｃａｕｓｅｉｔｓｒｅａｃｔｉｏｎｐｒｏｄｕｃｔ ,ｃｙｃｌｏ ｈｅｘａｎｅｉｓａｎｉｍｐｏｒｔａｎｔｉｎｄｕｓｔｒｉａｌｉｎｔｅｒｍｅｄｉａｔｅｕｓｅｄｉｎｔｈｅｐｒｏｄｕｃｔｉｏｎｏｆＮｙｌｏｎ 6ａｎｄＮｙｌｏｎ 6 6 [1] .Ｂｅｎｚｅｎｅｈｙｄｒｏｇｅｎａｔｉｏｎｏｆｂｏｔｈｔｈｅｌｉｑ ｕｉｄｐｈａｓｅａｎｄｇａｓｐｈａｓｅｕｎｄｅｒｄｉｆｆｅｒｅｎｔｃａｔａｌｙ ｓｉｓｗｅｒｅｒｅｐｏｒｔｅｄ[2 ,3 ] .Ｒ…