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MmNi     

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。     

非晶态和纳米结晶MmNi4.2Al0.8合金及其储氢性能

介绍了利用机械合金化制备非晶态和纳米结晶MmNi4.2Al0.8合金的工艺及此类材料的储氢性能研究的新成果,并对其进行了讨论。     

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。     

非晶态和纳米结晶MnNi4.2A10.8合金及其储氢性能

介绍了利用机械合金化制备非晶态和纳米结晶MmNi4.2Al0.8合金的工艺及此类材料的储氢性能研究的新成果，并对其进行了讨论。     

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 %。     

Mg2Ni系储氢合金电化学性能的研究

用固态扩散和机械球磨砺法制备出纳米级Ｍｇ２Ｎｉ、Ｍｇ１．７Ａｌ０．３Ｎｉ储合金，其电化学性能超过用传统方法制德的合金。驻卵是试表明：该合金放压平台（电压超过１．２Ｖ）较高：在２００ｍＡ／ｇ放电电流密度下，合金充放电循环５０次，容量仍保持在２００ｍＡｇ／ｇ以上。Ｘ射线行射分析表明；随着球磨时间延长，衍射峰的宽化程度变大，强度逐渐减弱，１２小时后变化减缓。这是由于晶粒尺寸较小。缺陷及应力密度增加入。合     

硼的添加对Mg2Ni储氢合金吸放氢性能的影响

镁系储氢合金有着价格低廉、储氢量大等优点,作为机载储氢材料有着广泛的应用前景,但其过高的氢分解温度,过慢的分解速度等缺点制约着实际应用.采用机械球磨制备出Mg2 Ni-xB(x =0％,1％,5％,10％,15％)系列储氢合金.通过XRD分析了合金的物相结构,采用P-C-T测试仪测定了合金的吸放氢性能,研究了添加不同含量的B对Mg2Ni合金吸放氢性能的影响.研究结果表明,B的添加对合金在200和300℃下吸放氢性能的改善作用不明显,但添加B的合金在400℃下的吸氢量均较Mg2Ni高,B的添加量由1％增至15％的合金吸氢量分别为3.09％,3.00％,2.81％,2.84％,而Mg2Ni的吸氢量则只有2.60％.随着B含量的增加,含B合金吸氢量略有降低;在含B的试样中,含5％B的合金吸氢速率最大,仅需180 s便能完成吸氢.所有含B合金的放氢平台均较Mg2Ni高且较为平坦.本次实验表明,B的添加量对合金性能的提升存在一个最优值,本次实验结果显示,添加5％B相对较好地改善合金的储氢性能,提高合金吸氢量和放氢平台压的同时能保持较快的吸氢速率.     

ZrFe_(1.95-x)Mn_xV_(0.10)(x=0,0.05,0.10,0.15)合金的储氢性能研究

利用磁悬浮感应熔炼法制备了ZrFe1.95-xMnxV0.10(x=0,0.05,0.10,0.15)高坪台压储氢合金。采用X射线衍射分析(XRD)、扫描电子显微镜(SEM)和Sievert's体积法研究了Mn部分取代Fe对ZrFe1.95V0.10合金的相结构、吸/放氢PCT性能及吸氢动力学性能的影响。XRD结果表明,当x≤0.10时合金均为C15型立方Laves单相结构,且随着Mn含量的增加,晶格常数逐渐增大;当x=0.15时合金中出现C14型六方Laves第二相,晶格常数略有降低;随着Mn取代量的增加,合金的活化性能改善,滞后系数降低,但坪台斜率增大,放氢坪台压由2.27MPa降至1.12 MPa(243 K下),储氢容量先增后减,在243 K下ZrFe1.85Mn0.10V0.10合金具有最大的储氢容量1.69%(n(H)/n(M)=1.13)及最快的吸氢速率t0.9为46 s。     

Ti/Cr比对(VFe)50Ti26-xCr24+x(0≤x≤2.0)储氢合金吸放氢性能的影响

为研究不同Ti/Cr比对(VFe)50Ti26-xCr24+x(0≤x≤2.0)储氢合金吸放氢性能的影响规律,采用FeV80中间合金制备了低成本储氢合金并系统研究了储氢合金的吸放氢性能及组织结构.PCT及XRD实验结果表明:随着Ti/r比的降低(x的增加),合金的吸放氢量均呈现减小的趋势,放氢平台压则不断增大,所有的合金均由主相BCC及稀土氧化物CeO2相组成,主相BCC的晶格常数随着Ti/Cr比的降低而减小.     

Microstructure and Hydrogen Absorption Pro-perties of Mg/MmNi_(5-x) (CoAlMn)_x Composite Prepared by Me chanical Alloying

Microstructure and Hydrogen Absorption Pro-perties of Mg/MmNi_(5-x) (CoAlMn)_x Composite Prepared by Mechanical Alloying     

Microstructure and improved hydrogen storage properties of Mg based alloy powders prepared by modified milling method

Abstract

In this study, the modified preparation method of combining planetary and vibratory ball milling was proposed to prepare Mg based hydrogen storage alloy powders. The comparison of micromorphology and hydrogen storage behaviour between Mg₂Ni prepared using the modified and conventional preparation methods were investigated experimentally. The comparison results showed that the combination of first planetary and then vibratory ball milling has more favourable effect on improving both the kinetics and the thermodynamics of ball milled Mg₂Ni alloys. The sample synthesised by first planetary milling for 40 h and then vibratory milling for 30 h has faster hydrogen absorption kinetics and lower dehydriding onset temperature than those prepared by the single method of planetary or vibratory milling and hydriding combustion synthesis owing to its popcorn-like microstructure. Moreover, this kind of modified method reduces the reaction enthalpy and activation energy by up to ～18 and 22% respectively.     

机械合金化制备Mg76-xTi12+xNi9Cr3(x=4,8,12,16)合金贮氢性能的研究

采用机械合金化制备Mg(76-x)Ti(12+x)Ni9Cr3(x=4,8,12,16)合金,通过X射线衍射(XRD)、热分析(DSC)、扫描电子显微镜(SEM)和压强-成分-温度(PCT)分析等方法对合金进行分析和表征.结果表明:Mg(76-x)Ti(12+x)Ni9Cr3(x=4,8,12,16)合金相主要由Mg2...     

TiFe储氢合金的电化学性能研究

研究了机械合金化（MA）、真空电弧熔炼、熔炼后短时间球磨、退火和辐射照对TiFe合金电化学性能的影响。短时间球磨可提高TiFe合金放电容量和倍率放电性能,高能辐照可以激活电极表面活性,促进活化;机械合金化可以降低电极极化,增加循环寿命;退火对TiFe合金的电化学性能不利,同时,对真空电弧熔炼TiFe合金在高温时的电化学性能作了初步研究。     

LaNi_(5-x)Al_x贮氢合金的研究

本研究用Ａｌ置换ＬａＮｉ５合金中的部分Ｎｉ，得到一系列ＬａＮｉ５－ｘＡｌｘ（ｘ＝０．１，０．３，０．５）贮氢合金。对这些合金的吸放氢热力学和动力学性能的实验研究表明，随着Ａｌ的加入及Ａｌ含量的增加，贮氢合金的平台氢压降低，吸氢量有所减少，而吸放氢速度有所增加。通过对合金及其氢化物晶体结构的ＸＲＤ分析，发现Ａｌ的加入并未使晶体结构类型发生变化，只是晶格常数变大；ＬａＮｉ５－ｘＡｌｘ合金吸氢后原晶体结构也未发生变化，但其晶格常数增加较大。     

Kinetics of Hydrogen Absorption in MmNi_（3．55）Co_（0．75）Mn_（0．4）Al_（0．3） Alloy

ＫｉｎｅｔｉｃｓｏｆＨｙｄｒｏｇｅｎＡｂｓｏｒｐｔｉｏｎｉｎＭｍＮｉ_（３．５５）Ｃｏ_（０．７５）Ｍｎ_（０．４）Ａｌ_（０．３）ＡｌｌｏｙＬｉｎＱｉｎ（林勤），ＹｕＺｈｅｎｔａｏ（于振涛），ＹｅＷｅｎ（叶文）（ＵｎｉｖｅｒｓｉｔｙｏｆＳｃｉｅｎｃｅａ...     

（Ag—Cu28）80-Inx—Sn20-x合金焊粉的制备及熔化特性研究

用机械合金化法来制备(Ag-Cu28)80-Inx-Sn20-x合金焊粉。利用差示扫描量热仪(DSC)、X-射线衍射仪(XRD)及扫描电子显微镜(SEM)和Simple-PCI软件对制备合金粒子的熔化特性、物相、微观结构和粒度分布等进行表征分析。研究结果表明:机械合金化法可以有效的制备(Ag-Cu28)80-Inx-Sn20-x合金焊粉。组分为(Ag-Cu28)80-In10.5-Sn9.5合金焊粉的熔化温度最低为490.9℃,其物相组成主要为富Ag相和-βCu81Sn22相。球磨30 h,(Ag-Cu28)80-Inx-Sn20-x体系合金化完全。球磨至80 h,合金粉体的平均尺寸约为47.64μm,铺展率为110.76 cm2/g。     

Phase evolution,hydrogen storage thermodynamics and kinetics of ternary Mg_(90)Ce_5Sm_5 alloy

Greatly stable thermodynamics and sluggish kinetics impede the practical application of Mg-based hydrogen storage alloys.The modifications of composition and structure are important strategies in turning these hydrogen storage properties.In this study,Mg-based Mg_(90)Ce_5 Sm_5 ternary alloy fabricated by vacuum induction melting was investigated to explore the performance and the reaction mechanism as hydrogen storage material by X-ray diffraction(XRD),scanning electron microscope(SEM),transmission electron microscopy(TEM) and pressure-composition isotherms(PCI) measurements.The results indicate that the Mg-based Mg_(90)Ce_5 Sm_5 ternary alloy consists of two solid solution phases,including the major phases(Ce,Sm)5 Mg_(41) and the minor phases(Ce,Sm)Mg_(12).After hydrogen absorption,these phases transform into the MgH2 and(Ce,Sm)H_(2.73) phase,while after hydrogen desorption,the MgH2 transforms into the Mg phase,but the(Ce,Sm)H2.73 phases are not changed.The alloy has a reversible hydrogen capacity of about 5.5 wt% H_2 and exhibits well isothermal hydrogen absorption kinetics.Activation energy of 106 kJ/mol was obtained from the hydrogen desorption data between 573 and 633 K,which also exhibits the enhanced kinetics compared with the pure MgH2 sample,as a result of bimetallic synergy catalysis function of(Ce,Sm)H_(2.73) phases.The rate of hydrogen desorption is controlled by the release and recombination of H_2 from the Mg surface.Furthermore,the changes of enthalpy and entropy of hydrogen absorption/desorption were calculated to be-80.0 kJ/mol H_2,-137.5 J/K/mol H_2 and 81.2 kJ/mol H_2,139.2 J/K/mol H_2,respectively.     

Effect of praseodymium substitution for lanthanum on structure and properties of La0.65-xPrxNd0.12Mg0.23Ni3.4Al0.1（X=0.00-0.20） hydrogen storage alloys

In order to investigate the effect of substituting La with Pr on structural and hydrogen storage properties of La-Mg-Ni system (AB3.5-type) hydrogen storage alloys, a series of La0.65-xPrxNd0.12Mg0.23Ni3.4Al0.1(x=0, 0.10, 0.15, 0.2) hydrogen storage alloys were prepared. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) analyses revealed that two alloys (x=0.0 and 0.10) were composed of (La, Mg)2(Ni,Al)7 phase, La(Ni,Al)5 phase and (La,Mg)Ni2 phase, while other alloys (x=0.15 and 0.20) consisted of (La,Mg)2(Ni,Al)7 phase, La(Ni,Al)5 phase, (La,Mg)Ni2 phase and (La, Mg)(Ni,Al)3 phase. All alloys showed, however, only one pressure plateau in P-C isotherms. The Pr/La ratio in alloy composition influenced hydrogen storage capacity and kinetics properties. Elec-trochemical studies showed that the discharge capacity decreased from 360 mAh/g (x=0.00) to 335 mAh/g (x=0.20) as x increased. But the high-rate dischargeability (HRD) of alloy electrodes increased from 26% (x=0.00) to 56% (x=0.20) at a discharge current density of Id=1800 mA/g. Anode polarization measurements were done to further understand the electrochemical kinetics properties after Pr substitution.