MmNi5-x(CoAlMn)x/Mg纳米晶复合储氢合金的吸氢性能

研究了机械合金化制备的ＭｍＮｉ５－ｘ（ＣｏＡｌＭｎ）ｘ／Ｍｇ纳米晶复合储氢合金的吸氢特性。通过测定不同镁含量的ＭｍＮｉ５－ｘ（ＣｏＡｌＭｎ）ｘ／Ｍｇ纳米晶复合储氢合金的吸氢ＰＣＴ曲线,考察了镁含量对其吸氢特性的影响。根据对吸氢速度的测定研究了机械合金化对储氢合金的吸氢动力学特性的影响。机械合金化制备的纳米晶复合储氢合金的活化性能与ＭｍＮｉＭ５－ｘ（ＣｏＡｌＭｎ）ｘ铸态合金相比有较大的提高,不需活化或只需一次活化即可吸氢,吸氢量及吸氢的动力学性能与铸态合金相比也有很大的提高。最后对机械合金化形成的纳米晶吸氢特性进行了分析。     

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。     

MnNi5—x（CoAlMn）lx／Mg纳米晶复合储氢合金的吸氢性能

研究了机械合金化制备的ＭｍＮｉ５－ｘ（ＣｏＡｌＭｎ）ｘ／Ｍｇ纳米晶复合储氢合金的吸氢特性。通过测定不同镁含量的ＭｍＮｉ５－ｘ（ＣｏＡｌＭｎ）ｘ／Ｍｇ纳米晶复合储氢合金的吸氢ＰＣＴ曲线，考察了镁含量对其吸氢特性的影响。     

镁基储氢复合材料放氢过程相转变速率研究

用机械合金化方法，在充氢球磨条件下，经不同时间球磨，制备Mg—Ni—MnO2储氢材料。用自行研制的储氢性能测试装置对这种材料放氢过程中的相转变速率进行了测试，并与经相同的球磨工艺制备的Mg—Ni、Mg—MnO2储氢材料的储氢性能进行了比较。试验结果表明：球磨时间对Mg—Ni—MnO2储氢材料的粒度有影响；颗粒大小对放氢过程的相转变速率有影响。颗粒越小，相转变速率的相对峰值越大，完成相变所用的时间相对要短；Ni与MnO2同时催化的镁基储氢材料放氢性能明显高于Ni或MnO2单独催化的储氢材料。     

机械合金化纳米晶材料研究进展

综述了机械合金化制备纳米晶材料的研究进展，重点介绍了高强度铝合金，铜合金，难熔金属化合物，金属储氢材料，复相烯土永磁材料等几类机械合金化纳米晶材料的制备与组织性能，指出了机械合金化技术在纳米晶材料制备方面的优势及应用前景。     

纳米Mg2Ni-1.00%Pd的吸放氢特性研究

采用机械合金化法制备了MgaNi-1．00％Pd（质量分数）合金粉末，用XRD及AFM等分析表征了材料吸放氢前后相和微观结构的变化，测定了Mg2Ni-1．00％Pd合金的吸放氢动力学曲线和PCT曲线。结果表明，机械合金化制备的MgaNi-1．00％Pd合金粉末颗粒尺寸在10—50nm之间；添加1．00％Pd机械球磨，可显著地改善纳米Mg2Ni合金的吸，放氢动力学性能，在初始氢压为1．17MPa、温度为423和473K时，同熔炼法制备的合金相比，材料无需活化即可快速吸氢；PCT曲线上有明显的坪台区，而且坪宽较长，有一定的滞后效应且滞后系数随温度的升高而降低；同熔炼法制备的MgaNi合金相比，纳米MgaNi-1．00％Pd合金吸氢时的焓变值减小，放氢时焓变值增加，可逆贮氢容量为3．0％H2。     

机械合金化制备纳米级超细晶材料

机械合金化是一种很有发展前景的固态合金化方法 ,已成功地应用于制备纳米级超细晶弥散强化材料、磁性材料、超导材料、纳米晶材料等。介绍了机械合金化技术制备纳米级超细晶材料的发展及其工艺过程以及采用该技术制备的纳米级超细晶材料的力学性能、磁性能和储氢性能。     

活化对镁基复合储氢材料结构及性能的影响

机械球磨镁、镍、石墨的混合物制备的镁碳储氢材料,在容积500mL高压釜中进行活化和吸氢。通过电子透射电镜和电子衍射照片,发现活化过程是物料细化和粉化的过程,同时也是物料晶化的过程。物料粒度和晶体结构的变化使物料储氢性能发生了改变,热重分析和差示扫描量热分析表明,活化17次的物料储氢量达4.53%,放氢温度降低至290℃。     

镁碳纳米储氢材料的制备及其性能的研究

用镁与炭化无烟煤混合后进行充氢球磨的方法,制备镁碳储氢材料。运用扫描电镜和透射电镜对储氢材料的粒径、微观形貌及晶形结构进行了表征,运用热重分析仪和差示扫描量热仪对材料的吸放氢性能进行了测试。实验发现,在镁中添加碳进行充氢球磨时,可以在5h内使粒径达到50-100nm。随着碳添加量的增大,镁碳储氢材料的储氢量下降,放氢温度升高。材料Mg3.0C2.0(碳添加量40%)的储氢量2.61%,放氢温度295℃。活性金属Mo对镁碳材料吸放氢性能有着明显的改善作用。     

镁基贮氢合金制备方法的研究进展

就镁基贮氢合金的主要制备方法：熔炼法、机械合金化法、置换扩散法、固相扩散法、氢化燃烧合成法的研究进展进行了报道,讨论了不同方法对合金性能的影响。研究表明,镁基贮氢合金吸氢量大（MH2为7.6%）,并具有良好的吸氢性能。     

钛镍球磨产物的分析及其贮氢性能研究

通过Ｘ射线衍射分析，Ｘ射线光电子能谱分析，研究了两种比例（Ｔｉ：Ｎｉ＝５０：５０，Ｔｉ：Ｎｉ＝６５：３５）的钛镍金属粉末的球磨产物。研究了产物的吸放氢性能，发现产物易活化，并随着Ｔｉ含量的增加，吸氢量增大。     

Structural and Electrochemical Characteristics of Mg0.94 La0.06 Ni AlloyPrepared by Ball Milling

The amorphous Mg0.94Lao.o6Ni alloy was synthesized by ball milling for different time at 400 r min^-1. Electrochemical performances of the alloy electrodes were investigated and the results show that the specimens would reach their maximum electrochemical discharge capacities at the first charge/discharge cycle. The cyclic tests and X-ray diffraction(XRD) results show that discharge capacities would decrease rapidly due to the crystallization of the amorphous and the oxidization of magnesium on the particle surface during the electrochemical charge/discharge cycling. In addition, the DTA and SEM results reveal that the thermal stabilities will be improved and the size of the alloy will be decreased with the ball-milling time. The amorphous Mgo.96Lao.04Ni alloy prepared by ball milling for 40 h at 400 r min^-1 shows the bestelectrochemical properties.     

钒基固溶体贮氢合金研究现状

贮氢合金是MH/Ni电池技术的核心,为了满足镍氢电池作为动力电池的要求,开发低成本、高功率、高稳定性的贮氢合金,近年来人们在进一步提高其电化学性能方面做了大量工作。钒基固溶体贮氢合金是近年来开发的一种新型高性能贮氢材料。介绍了氢钒反应特点和钒基固溶体合金的制备方法,对无电化学活性的基质合金,用元素取代、合成复合合金和多相合金等多种方法,得到一些性能较好的负极材料。并对钒基固溶体贮氢合金的研究及开发现状进行了综述,指出了固溶体合金的研究方向。     

稀土在Ni/MH电池中应用研究

综述了稀土在N i/MH电池中的作用机理。贮氢合金中稀土的含量和组成改变合金的微晶结构,影响合金的吸放氢特性。镍电极中掺杂稀土添加剂一方面可以有效地提高析氧过电位,改善N i/MH电池高温性能。另一方面稀土的掺杂使N i(OH)2晶格发生畸变,改善材料的质子扩散性能,减少电化学反应阻抗。此外,电解液中引入稀土化合物,可增大电极表面的活性中心。阐述了稀土是改善N i/MH电池性能的一种有效的活性材料和添加剂。     

Hydrogen storage thermodynamic and kinetic characteristics of PrMg12-type alloys synthesized by mechanical milling

To improve the hydrogen storage performance of PrMg_(12)-type alloys,Ni was adopted to replace partially Mg in the alloys. The PrMg_(11)Ni+x wt.% Ni( x = 100,200) alloys were prepared via mechanical m illing. The phase structures and m orphology of the experim ental alloys were investigated by X-ray diffraction and transm ission electron microscopy. The results show that increasing milling time and Ni content accelerate the form ation of nanocrystalline and am orphous structure. The gaseous hydrogen storage properties of the experim ental alloys were determ ined by differential scanning calorim etry( DSC) and Sievert apparatus. In addition,increasing milling time makes the hydrogenation rates of the alloys augment firstly and decline subsequently and the dehydrogenation rate always increases. The maximum capacity is 5. 572 wt. % for the x = 100 alloy and 5. 829 wt. % for the x = 200 alloy,respectively. The enthalpy change( ΔH),entropy change( ΔS) and the dehydrogenation activation energy( E_k~(de)) markedly lower with increasing the milling time and the Ni content due to the generation of nanocrystalline and amorphous structure.     

Structure and electrochemical hydrogen storage characteristics of Ce-Mg-Ni-based alloys synthesized by mechanical milling

The substituting Mg with Ni and milling as-cast alloy with Ni were adopted to obtain nanocrystalline/amorphous CeMgnNi+x wt.%Ni(x=100,200) alloys and promote the electrochemical hydrogen storage performances of CeMg_(12)-type alloys.Analyzing the structural features of the alloys provided a mechanism for ameliorating the electrochemical hydrogen storage properties.The electrochemical tests demonstrated that all the alloys just needed one cycle to be activated.Rising Ni proportion had an obvious role on charge-discharge reaction.The discharge capacities of the as-milled(60 h) alloys increased sharply from 182.0 mAh/gfor x=100 alloy to 1010.2 mAh/gfor x=200 alloy at current density of 60 mAh/g.Furthermore,milling time largely determined the performances of electrochemical reaction.The discharge capacity continued to grow along with prolonging milling time,while the cycle stability obviously decreased for x=100 alloy,and first declined and then augmented for the x=200 alloy with milling time extending.In addition,there was an optimal value with milling time varying for the high rate discharge abilities(HRD),which was 80.3%for x=100 alloys and 86.73%for x=200,respectively.     

钒基固溶体型贮氢合金的研究进展

金属钒具有吸氢量大、抗粉化性能好等优点，但是有效吸氢量较低，只有一半的氢能够释放出来，没有实用价值。在V-Ti二元合金的基础上形成的三元合金V-Ti-M(M代表Cr，Mn，Fe，Ni等)具有良好的贮氢性能。Ti／Cr比对V-Ti-Cr合金性能影响很大，Ti/Cr比值为0．75时V-Ti-Cr合金具有最大的贮氢量和有效吸氢量，同时热处理可以有效地提高V-Ti-Cr合金的有效吸氢量，并降低V的使用量。添加Mn的三元合金具有BCC和Laves相双相结构。V-Ti-Fe合金的贮氢量很高，并有希望利用便宜的钒铁做钒源。此外，V基固溶体合金还可以用于镍氢电池负极，如V-Ti-Ni合金具有很高的放电容量，目前需要解决其循环稳定性差和成本高的问题。     

稀土贮氢电池的发展现状及对策

本文综述了我国稀土贮氢电池的主要发展状况。1990年前我国已能生产作为电池(Ni/MH)负极材料的稀土贮氢合金，1990年初期就开始制造电池（Ni／MH)，且在1995年后逐步走向工业化生产水平。目前我国的这种电池的原料供给能力、电池的生产技术及装备、检测手段、电池的综合技术性能等方面都处于世界先进水平。     

Effect of annealing treatment on hydrogen storage properties of La-Ti-Mg-Ni-based alloy

The present study dealt with investigations on the effects of annealing on the hydrogen storage properties of La 1.6 Ti 0.4 MgNi 9 alloys.The experimental alloys were prepared by magnetic levitation melting followed by annealing treatment.For La 1.6 Ti 0.4 MgNi 9 alloys,LaNi 5,LaNi 3 and LaMg 2 Ni 9 were the main phases,Ti 2 Ni phase appeared at 900℃.Annealing not only enhanced the maximum and effective hydrogen storage capacity,improved the hydrogen absorption/desorption kinetics,but also increased the discharge capacity.The cyclic stability had been improved markedly by annealing,e.g.,when the discharge capacity reduced to 60% of maximum discharge capacity,the charge/discharge cycles increased from 66(as-cast) to 89(annealed at 800℃) and 127 times(annealed at 900℃).La 1.6 Ti 0.4 MgNi 9 alloy annealed at 900℃ exhibited better electrochemical properties compared to the other two alloy electrodes.     

Highly ameliorated gaseous and electrochemical hydrogen storage dynamics of nanocrystalline and amorphous LaMg12-type alloys prepared by mechanical milling

Nanocrystalline and amorphous LaMg12-type alloy-Ni composites with a nominal composition of LaMg11 Ni+x wt.% Ni (x=100, 200) were synthesized via ball milling.The influences of ball mill-ing duration and Ni adding amount x on the gaseous and electrochemical hydrogen storage dynamics of the alloys were systematically studied.Gaseous hydrogen storage performances were studied by a differential scanning calorimeter and a Sievert apparatus.The dehydrogenation activation energy of the alloy hydrides was evaluated by Kissinger method.The electrochemical hydrogen storage dynam-ics of the alloys was investigated by an automatic galvanostatic system.The H atom diffusion and ap-parent activation enthalpy of the alloys were calculated.The results demonstrate that a variation in Ni content remarkably enhances the gaseous and electrochemical hydrogen storage dynamics perform-ance of the alloys.The gaseous hydriding rate and high-rate discharge (HRD) ability of the alloys ex-hibit maximum values with varying milling duration.However, the dehydriding kinetics of the alloys is always accelerated by prolonging milling duration.Specifically, rising milling time from 5 to 60 h makes the hydrogen desorption ratio (a ratio of the dehydrogenation amount in 20 min to the saturat-ed hydrogenation amount) increase from 57% to 66% for x=100 alloy and from 57% to 70% for x=200.Moreover, the improvement of gaseous hydrogen storage kinetics is attributed to the descending of dehydrogenation activation energy caused by the prolonging of milling duration and growing of Ni content.