一种新型稀土合金MLNi_(4.5)Al_(0.5)的贮氢性能

本文研究了新型稀土合金ＭＬＮｉ４．５ Ａｌ０．５ 的ＰＣＴ性能、动力学特性、活化性能、循环性能及抗ＣＯ 毒化性能,并与ＬａＮｉ５ 合金进行了比较,结果表明,ＭＬＮｉ４．５ Ａｌ０．５ 的活化性能、循环稳定性及抗ＣＯ 毒化性能均优于ＬａＮｉ５,是一种具有应用前景的稀土贮氢合金。     

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。     

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。     

Al替代Ni对LaNi5-xAlx性能的影响

通过对LaNi5-xAlx(x=0.25,0.5,0.75,1.0)系合金及其氢化物的晶体结构XRD分析,发现Al的添加并未改变合金的晶体结构类型,只是晶格常数变大。对合金的热力学性能实验研究表明,随着Al含量的增加,贮氢合金的平衡氢压降低,吸氢量减少,滞后现象得到改善,焓变值的绝对值增加。对合金的动力学性能实验研究表明,吸氢速度随x的增加而减慢。     

Nd含量对稀土储氢合金REB5性能的影响

设计了用Ｎｄ替代Ｌａ的系列Ｌａ１－ｘＮｄｘＢ５合金，并分析测试了不同含量Ｎｄ的储氢合金的性能。实验发现，Ｌａ１－ｘＮｄｘＢ５合金的晶胞体积与ｘ呈线性关系；平衡氢压与ｘ呈曲线关系；吸氢量与放电容量在ｘ＝０．２最高；循环寿命随Ｎｄ含量增加呈增加的趋势     

稀土对Al、Zn及其合金11年大气腐蚀的影响

本文就Ａｌ、Ｚｎ 及其稀土合金和Ｆｅ等１２ 种试样进行了长达１１ 年的大气腐蚀试验。结果表明,Ａｌ、Ｚｎ及其合金中添加适量稀土可以不同程度提高其耐蚀性。特别是Ａｌ、Ｚｎ 合金中加入稀土后提高耐蚀性明显,Ａｌ－４３．４％ Ｚｎ－１．６％ Ｓｉ及Ｚｎ－５％ Ａｌ合金中加入０．１％ ＲＥ耐蚀性分别提高０．５ 倍和１．０５ 倍。稀土的适宜加入量小于０．５％ 。     

Al—Ti合金合镀镀层的耐蚀性

研究不同含钛量的Ａｌ－ＴＩ合金电镀镀层在０．５ｍｏｌ／ＬＨ２ＳＯ４、０．１％ＮａＣｌ、３．５％ＮａＣｌ水溶液中的耐蚀性能,８００℃抗高温氧化性能以及３００℃、％ＳＯ气氛下的抗硫化性能,并测定了镀层的硬度,Ａｌ－Ｔｉ合金镀怪在稀Ｈ２ＳＯ４及含Ｃｌ的溶液中具有优良的耐性能以及具有良好的抗高温氧化性能及耐硫化性能,增加镀层中的含钛量,则可进一步提高Ａｌ－Ｔｉ合金钛层的耐蚀性。     

MMNi_5基贮氢合金的电极特性

测定了ＭＭＮｉ５基贮氢合金的电极特性。用快淬法制成的ＭＭ（０．９）Ｔｉ（０．１）Ｎｉ（３．９）Ｍｎ（０．４）Ｃｏ（０．４）Ａｌ（０．３）贮氢合金电极的循环寿命和快速放电能力显著提高，其３００次充放电循环后电容量仅下降１８％，这与合金中微晶组织的形成有关，而感应熔炼制成的ＭＭ（０．９）Ｔｉ（０．１）Ｎｉ（３．９）Ｍｎ（０．４）Ｃｏ（０．４）Ａｌ（０．３）贮氢合金电极２００次循环后电容量下降３９％，经１０００℃３ｈ退火后，其３００次循环后电容量下降为２７％。     

MmNi_(3.8-x)Co_xMn_0.4Al_0.3合金的结构与电化学性能

本文对ＭｍＮｉ３．８－ｘＣｏｘＭｎ０．４Ａｌ０．３（ｘ＝０．２、０．４、０．５、０．６、０．７和０．９）进行了物相分析和电化学测试。发现Ｃｏ部分取代Ｎｉ可在不改变合金相结构和起始活化性能的前提下改善合金的循环稳定性，但同时降低了合金的起始放电容量特别是高倍率放电容量。合金的初始放电电压随Ｃｏ含量的增加而增加，但放电电压平台特性随Ｃｏ含量的增加而劣化。Ｃｏ含量对合金的容量、循环稳定性的影响并不是线性的，而是存在拐点，拐点前后合金上述电化学性能随Ｃｏ含量变化的幅度有着较大的差别。     

AB5型贮氢合金结构分析

贮氢合金的电极性能取决于贮氢合金的微结构。从晶体结构、电子结构及化学键结构等各方面对市场上广泛应用的AB5型贮氢合金的结构进行综述，同时讨论合金结构与合金吸放氢性能之间的关系。     

Structure of Sn Doped AB_5 Non-Stoichiometric Hydrogen-Absorbing Alloys-Ⅰ

ＡＢ5 ｔｙｐｅａｌｌｏｙｓａｒｅｗｉｄｅｌｙｕｓｅｄａｓｔｈｅｎｅｇａｔｉｖｅｍａｔｅｒｉａｌｓｏｆｎｉｃｋｅｌｍｅｔａｌｌｉｃｈｙｄｒｉｄｅｂａｔｔｅｒｉｅｓ (Ｎｉ ＭＨ )ｂｅｃａｕｓｅｏｆｔｈｅｅｘｃｅｌｌｅｎｔｐｅｒｆｏｒｍａｎｃｅｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｒａｐｉｄａｃｔｉｖａｔｉｏｎ ,ｈｉｇｈｅｎｅｒｇｙ ｓｔｏｒａｇｅｄｅｎｓｉｔｙ .Ｗｉｔｈｔｈｅｄｅｖｅｌｏｐ ｍｅｎｔｏｆｅｌｅｃｔｒｉｃｅｑｕｉｐｍｅｎｔｗｏｒｋｉｎｇａｔｌａｒｇｅｃｕｒｒｅｎｔ ,ｔｈｅｄｉｓｃｈａｒｇｅｒ…     

Mg_(10)Al_((7-x))Li_2Ti_x(x=0,1,2,3)合金的制备及储氢性能研究

在氩气保护下,采用机械合金化法制备Mg_(10)Al_((7-x))Li_2Ti_x(x=0,1,2,3)合金,并通过XRD、SEM以及DSC等手段对合金进行表征。结果表明,适量的Ti替代Al可以提高合金的吸氢量、降低合金的初始氢化/脱氢温度和提高合金氢化/脱氢动力学性能。Mg_(10)Al_((7-x))Li_2Ti_x(x=1,2,3)合金样品比Mg10Al7Li2合金的初始氢化温度都降低了62K,而初始脱氢温度则分别降低了77、98和59K。当Ti的替代量为x=2时,合金的综合储氢性能最好。     

Phase Structure and Electrochemical Properties of Rare Earth Based Hydrogen Storage Alloys

The rare earth based hydrogen storage alloys MmxM1 1 - x ( Ni3.55 Co0.75 Mn0.4 A10.3 ) ( x = 0 ～ 0.5 ) were investigated in this work.Adjusted Ml: Mm ratio to change the content of La,Ce,Pr and Nd in the alloys and then to change the phase structure, the influences of phase structure on the electrochemical properties were analyzed.The results indicate that the main phase of all alloys is LaNi5 with CaCu5 type structure and the crystal lattices constants of LaNi5 are changed with increasing x value, i.e, decreased a-axis, increased c-axis and axis ratio and nonlinear decreased crystal volume.The crystal volume of the alloy with x = 0.3 is larger than others.There is second phase A1LaNi4 in alloys when x≥0.3, which decrease the discharge capacity, but increase the cycling stability and high rate discharge ability.Compared comprehensively, the alloy with x = 0.3 shows the higher discharge capacity and the better cycling stability.     

LaNi5-xAlx合金的Al含量对吸氢量和平衡氢压的影响

在研究LaNi5-xAlx合金系的结构特性、储氢性能及热力学性能的基础上，分析讨论了Al的加入使LaNi5-xAlx合金系晶胞体积增大的同时，引起了晶格的各向异性膨胀，以及这种非平衡的空间增长对吸氢量和平衡氢压的影响。结果表明，添加Al的合金化影响了原子间的相互作用，导致了原子间距的重新调整，从而导致了储氢性能的变化。根据实验数据导出了LaNi5-xAlx金属间化合物中的Al含量x与平台压力间的对应关系。晶格的各向异性膨胀与吸氢量之间呈很好的线性关系；Seitz半径随Al的加入而增大，有利于平衡氢压的降低；同时吸氢量可能由于晶格畸变增大而减少。     

A study on hydrogen storage and electrochemical properties of La_（0.55）Pr_（0.05）Nd_（0.15）Mg_（0.25）Ni_（3.5） （Co_（0.5）Al_（0.5））_x （x=0.0, 0.1, 0.3, 0.5） alloys

The La0.55Pr0.05Nd0.15Mg0.25Ni3.5(Co0.5Al0.5)x(x=0.0, 0.1, 0.3, 0.5) alloys were prepared by magnetic levitation melting under an Ar atmosphere, and the effects of Co and Al on the hydrogen storage and electrochemical properties were systematically investigated by pressure composition isotherms, cyclic voltammetry, Tafel polarization and electrochemical impedance spectroscopy testing. The results showed that the alloy phases were mainly consisted of (La,Pr)(Ni,Co)5, LaMg2Ni9, (La,Nd)2Ni7 and LaNi3 phases, and the cell volumes of (La,Pr)(Ni,Co)5, LaMg2Ni9, (La,Nd)2Ni7 and LaNi3 phases expanded with Co and Al element added. The hydrogen storage capacity initially increased from 1.36 (x=0) to 1.47 wt.% (x=0.3) and then decreased to 1.22 wt.% (x=0.5). The discharge capacity retention and cycle stability of the alloy electrodes were improved with the increase of Co and Al contents. The La0.55Pr0.05Nd0.15Mg0.25Ni3.5(Co0.5Al0.5)0.3 alloy electrode possessed better electrochemical kinetic characteristic.     

Effect of Addition of Al on Crystal Structure Microtexture and Magnetostriction Coefficient in Tb0.3 Dy0.7 Fe1.95 Alloy

The effect of addition of A1 on crystal structure microtexture and magnetostrictioncoefficient in Tb0.3Dy0.7Fe1.95 alloy were studied.The results show that addition of A1 does not change crystal structure of alloy and the precipitates increase in the microtexture as addition of A1 increases.At a certain magnetic field, magnetostriction coefficient decreased as addition of Al increased.     

Hydriding and dehydriding characteristics of nanocrystalline and amorphous Mg20-xLaxNi10（X=0-6） alloys prepared by melt-spinning

In order to improve the hydrogenation and dehydrogenation performances of the Mg2Ni-type alloys, Mg was partially substituted by La in the alloy, and melt spinning technology was used for the preparation of the Mg20-xLaxNi10 (x=0, 2, 4, 6) hydrogen storage alloys. The structures of the alloys were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). It was found that no amorphous phase formed in the as-spun La-free alloy, but the as-spun alloys containing La held a major amorphous phase. When La content x≤2, the major phase in the as-cast alloys was Mg2Ni phase, but with further increase of La content, the major phase of the as-cast alloys changed into LaNi5+LaMg3 phase. Thermal stability of the as-spun alloys was studied by differential scanning calorimetry (DSC), showing that spinning rate was a negligible factor on the crystallization temperature of the amor-phous phase. The hydrogen absorption and desorption kinetics of the as-cast and as-spun alloys were measured using an automatically con-trolled Sieverts apparatus, confirming that the hydrogen absorption and desorption capacities and kinetics of the as-cast alloys clearly in-creased with rising La content. For La content x=2, the as-spun alloy displayed optimal hydrogen desorption kinetics at 200 ℃.     

Effect of electrolyte concentration on low-temperature electrochemical properties of LaNi5 alloy electrodes at 233 K

The effect of KOH electrolyte concentration on low-temperature electrochemical properties of LaNi5 alloy electrodes at 233 K was studied. The results indicated that the electrolyte concentration had great influence on discharge capacity and discharge voltage plateau of LaNi5 alloy electrode at 233 K, and the highest discharge capacity and discharge voltage plateau were both obtained at 6 mol/L KOH. When the KOH electrolyte concentration changed from 5 to 9 mol/L at 233 K, the high rate discharge ability (HRD) had the same change tendency as the diffusion coefficient, but the exchange current density did not change significantly, which implied that hydrogen diffusion was the control step at low temperature 233 K for discharge process of LaNi5 alloy electrode.     

Phase Structure and Electrochemical Characteristics of Ml（Ni3.55Co0.75Mn0.40Al0.30）5x （x=0.88, 0.92, 0.96, 1.00） Hydrogen Storage Alloys

The phase structure and electrochemical characteristics of Ml （（Ni3.55Co0.75Mn0.40Al0.30）sx （ x = 0.88, 0.92, 0.96, 1.00） hydrogen storage alloys were studied. The effect of the stoichiometric ratio on the phase structure and electrochemical characteristics was analyzed. The results of XRD reveal that all the alloys consist mainly of LaNi5 phase with the hexagonal CaCu5 structure. But a few of the diffraction peaks of La2Ni7 phase on XRD pattern are observed when x ≤ 0.92, and with decreasing x, the intensity of La2Ni7 diffraction peaks increases and the values of lattice parameters a and cell volume increase, c and c/a of LaNi5 phase decrease gradually. When x≥0.96, La2Ni7 phase disappears and the alloys become single CaCu5-type. The electrochemical tests show that the maximum discharge capacity, high rate dischargeability and low temperature dischargeability are improved to different degrees by adjusting the stoichiometric ratio.