ZrM2（M=Mn,V,Ni）相贮氢合金的相组成

本文采用Ｘ射线衍射Ｒｉｅｔｖｅｌｄ全谱拟合分析研究了ＡＢ２型Ｌａｖｅｓ相贮氢合金Ｚｒ（Ｍｎ０．４５－ｘＶｘＮｉ０．５５）２（ｘ＝０．１０－０．４０）的相组成和相含量。     

Electrochemical properties of TiV-based hydrogen storage alloys

The electrochemical properties of the super-stoichiometric TiV-based hydrogen storage electrode alloys(Ti0.8Zr0.2)(V0.533Mn0.107Cr0.16Ni0.2)x(x=2,3,4,5,6)were studied.It is found by XRD analysis that all the alloys mainly consist of a C14 Laves phase with hexagonal structure and a V-based solid solution phase with BCC structure.The lattice parameters and the unit cell volumes of the two phases decrease with increasing x.The cycle life.the linear polarization.the anode polarization and the electrochemical impedance spectra of the alloy electrodes were investigated systematically.The overall electrochemical properties of the alloy electrode are found improved greatly as the result of super-stoicfhiometry and get to the best when x=5.     

Properties of Zr-Ti-V-Mn-Ni hydride alloy

1　ＩＮＴＲＯＤＵＣＴＩＯＮＷｉｔｈｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｅｃｏｎｏｍｉｃｓａｎｄｃｉｔｙｔｒａｆｆｉｃｓ ,ｍｏｒｅａｎｄｍｏｒｅｏｉｌ ｐｏｗｅｒｅｄｖｅｈｉｃｌｅｓａｐｐｅａｒ,ｒｅｓｕｌｔｉｎｇｍｏｒｅｓｅｒｉｏｕｓｐｏｌｌｕｔｉｏｎｔｏｔｈ     

快速凝固钛钒系贮氢合金电化学性能研究

研究了快速凝固处理对钛钒系贮氢电极合金Ti0.8Zr0．2V2．4Mn0．48Cr0．72Ni0．9的相结构、特别是电化学性能的影响规律。XRD研究表明：合金主要由六方结构的C14 Laves相和体心立方结构的钒基固溶体相所组成，快速凝固减少了合金中C14 Laves相的含量。电化学性能分析表明：快速凝固降低了合金电极的最大放电容量，增加了电极的活化次数，提高了电极表面的反应阻抗，恶化了电极的动力学性能，但是却大大改善了合金电极的循环稳定性。     

CRYSTAL STRUCTURE AND ELECTROCHEMICAL PROPERTIESOF Zr(Mn1-xNix)2(0.40≤x≤0.75) HYDROGEN STORAGE ALLOYS

1. IntroductionAmong the binary alloys ZrMZ (M=V,Cr,Mn,Fe,Co,Mn etc.), ZrVZ and ZrCrZ all?Xscan absorb a large quantity of hydrogen to form hydride as ZrVZH6 and ZrCr,H..,[1].The effects of V or Cr atom sites substituted by nickel atom on the crystal structure andelectrochemical properties of the binary ZrVZ or ZrCrZ alloys were investigated extensivelydue to the higher hydrogen storage in binary alloys[Z13]. Many high-performance ABZ typeLaves phase electrode alloys based on Zr…     

快淬对Ti-V基BCC相合金相结构和储氢性能的影响

研究了快淬作用对Ti-28V-15Mn-10Cr合金的相结构和储氢性能的影响。XRD实验结果表明，快淬处理使得合金由BCC和C14Laves两相结构转变为单一的BCC相结构，同时合金的晶格常数随着快淬冷速的增加而增大。快淬作用能显著改善Ti-28V-15Mn-10Cr合金的吸放氢平台特性，从而导致合金放氢量的增加。然而，快淬处理也使得合金的放氢平台压下降以及活化性能变差。     

Synergistic effect between Laves phase and Zr Ni phases in Zr(MnVNi)_2 hydrogen storage alloys

１　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＡＢ２ｔｙｐｅＺｒｂａｓｅｄＬａｖｅｓｐｈａｓｅｈｙｄｒｏｇｅｎｓｔｏｒａｇｅａｌｌｏｙｓｈａｖｅｂｅｅｎｓｔｕｄｉｅｄｅｘｔｅｎｓｉｖｅｌｙｄｕｅｔｏｔｈｅｉｒｈｉｇｈｃａｐａｃｉｔｙ，ｌｏｎｇｃｙｃｌｅｌｉｆｅｔｉｍｅａｎｄｔｈｅｐｏｔｅｎｔｉａｌｔｏｂｅｃｏｍｅａｐｒｏｍｉｓｉｎｇｃａｎｄｉｄａｔｅｆｏｒＡＢ５ｔｙｐｅａｌｌｏｙｓｉｎＮｉＭＨｂａｔｔｅｒｉｅｓ［１，２］．ＵｎｌｉｋｅｔｈｅｃｏｍｍｏｎＡＢ５ｔｙｐｅｈｙｄｒｏｇｅｎｓｔｏｒａｇ…     

Ti对Zr—Mn—V—Ni系合金的微结构和电化学性能的影响

Ｚｒ－Ｍｎ－Ｖ－Ｎｉ合金中Ｚｒ－Ｎｉ金属间化合物与Ｌａｖｅｓ相共存,Ｚｒ０．５Ｔｉ０．５Ｍｎ０．２Ｖ０．６Ｎｉ１．２合金内形成了含Ｔｉ的ｂｃｃ相,选区电子衍射和ＥＤＳ能谱分析结果表明,ｂｃｃ相为Ｂ２型Ｒ相（Ｔｉ０．５Ｚｒ０．２）Ｎｉ,Ｔｉ取代部分Ｚｒ,改变了四元合金中Ｌａｖｅｓ相的晶胞参数和亚结构,非Ｌａｖｅｓ相的形成导致合金元素在各相间的重新分配,多相合金内Ｌａｖｅｓ相的晶胞参数合金的名义成分。     

Phase structure and electrochemical properties of melt-spinning alloy Zr(MnVNi)_(2.4)

1　INTRODUCTIONItiswellknownthatZr basedAB2 LavesphasealloyelectrodeshavehigherdischargecapacityandmuchbettercyclingstabilitythanthatofAB5alloysalthoughitisexpensivecomparedtoAB5alloys .HowtofurtherimprovetheratioofpropertiesandpriceofAB2 alloyshasbeendrawingtheinterestofmanyin vestigators .Someinvestigationsrevealedthatover stoichiometricAB5typealloyshadbettercharge dis chargecyclingstabilitythanstoichiometricalloys[15] ,andsomeover stoichiometricAB2 typealloysshowedhigherdischargec…     

Cluster-based composition rule for Laves phase-related BCC solid solution hydrogen storage alloys

A new cluster line approach for the composition rule of Laves phase-related BCC solid solution hydrogen-storage alloys was presented. The cluster line in a ternary phase diagram refers to a straight composition line linking a specific binary cluster to the third element. In the Laves phase-related BCC solid solution alloy system such as Ti-Cr-V, Ti-Cr tends to form binary Cr2Ti Laves phase while Ti-V and Cr-V to form solid solutions. This Laves phase is characterized by a close-packing icosahedral cluster Cr7Ti6. A cluster line Cr7Ti6-V is then constructed in this system. Alloy rods with a diameter of 3 mm of compositions along this line were prepared by copper-mould suction method. The alloy structure is found to vary with the V contents. Furthermore, the P-C-T measurements indicate that the cluster-line (Cr7Ti6)1-xVx alloys have large hydrogen storage capacities.     

（V30Ti35Cr25Fe10）97．5Si2．5合金的结构与吸放氢性能

采用XRD，SEM和PCT测试研究了（V30Ti35Cr25Fe10）97.5Si2.5（at％）合金的组织结构与吸放氢性能。结果表明：合金由BCC相和C14 Laves相组成，BCC相含量为75％，晶胞参数为α=0．3021nm，Laves相含量为25％，晶胞参数为α=0．4920nm和c=0．7996nm。由于含有大量的Laves相，合金具有良好的活化性能，室温下不需孕育期就可以快速吸氢，5min内达到吸氢饱和状态，饱和吸氢量达到2．98％（质量分数，下同）。在一定氢压下，合金的容量可由合金中BCC相和Laves相的容量按组分的含量进行线性组合而成。     

MICROSTRUCTURE AND ELECTROCHEMICAL CHARACTERISTICS OF Zr_(0.9)Ti_(0.1)(Ni_(1.1)Mn_(0.7)V_(0.2))_x METAL HYDRIDE ELECTRODE

The crystal structure, the phase composition and the electrochemical characteristics of Zr0.9Ti0.1(Ni1.1Mn0.7V0.2)x (x=0.90, 0.95, 1.00, 1.05) alloys were investigated by means of XRD, SEM, EDS and electrochemical measurements. It was shown that all alloys are multiphase with C15 Laves phase as a main phase along with C14 phase and some secondary phases. And the amounts of the C14 phase and secondary phases in the four alloys increases with decreasing x. The results indicated that the various stoichiometric ratios have great effects on the electrochemical characteristics such as the maximum discharge capacity, discharge rate capability and self-discharge properties etc. for Zr0.9Ti0.1(Ni1.1Mn0.7 V0.2)X (x=0.90, 0.95, 1.00, 1.05) alloys. The hyper-stoichiometric Zr0.9 Ti0.1(N1.1Mn0.7 V0.20)1.05 exhibits the maximum discharge capacity of 332mAh-g-1. The C14 phase and secondary phases seems to improve discharge rate capability of the alloys.     

MICROSTRUCTURE AND ELECTROCHEMICAL CHARACTERISTICS OF Zr0.9Ti0.01（Ni1.1.Mn0.7V0.2）x METAL HYDRIDE ELECTRODE

The crystal structure,the phase composition and the electrochemical characteristics of Zr0.9 Ti0.1(Ni1.1Mn0.7V0.2)x(x=0.90,0.95,1.00,1.05) alloys were investigated by means of XRD,SEM,EDS and electrochemical measurements.It was shown that all alloys are multiphase with C15 Laves phase as a main phase along with C14 phase and some secondary phases.And the amounts of the C14 phase and secondary phases in the four alloys increases with decreasing x.The results indicated that the various stoichiometric ratios have great effects on the electrochemical characteristics such as the maximum discharge capacity,discharge rate capability and self-discharge properties etc.for Zr0.9Ti0.1(Ni1.1Mn0.7V0.2)x(x=0.90,0.95,1.00,1.05)alloys.The hyper-stoichiometric Zr0.9Ti0.1(Ni1.1Mn0.7V0.20)1.05 exhibits the maximum discharge capacity of 332mAh·g^-1.The C14 phase and secondary phases seems to mprove discharge rate capability of the alloys.     

元素Ti对贮氢合金ZrMn0．7V0．2CO0．1Ni1．2相结构和电化学性能的影响

研究了元素Ti对贮氢电极合金ZrMn0.7V0.2Co0.1Ni1.2的相结构、相组成以及电化学性能的影响。结果表明，对于合金Zr1-xTix(Mn0.7V0.2Co0.1Ni1.2)，其母体合金的主相为C15型Laves相，并含有少量的非Laves相Zr7M10；但随着掺Ti量的增加，合金中出现C14型Laves相，而且其含量逐渐增加；在x=0．1～0．2时，合金中还出现少量的TiNi相，而在x=0．4～0．5时，非Laves相Zr7M10和TiNi相全部消失，说明元素Ti大量的掺杂抑制了第二相的产生：而且随着Ti含量的增加，合金中的C15型和C14型Laves相的晶格常数逐渐减小。电化学测试结果发现，当含Ti量x=0．2时，合金有最大放电容量Cmax为354mAh／g，在放电电流为300mAh／g条件下，高倍率放电性能比母体合金提高了15％。     

合金化对ZrMn2基Laves相贮氢合金相组成的影响

研究了Ni、V、Cr、Co、Fe、Cu和Ti等合金化元素取代ZrMn2 基Laves相贮氢合金的B侧或A侧对合金相组成的影响。结果表明 ,采用不同的元素对A侧或B侧进行部分取代 ,将引起ZrMn2 基合金相组成的变化。采用Ni取代Mn后 ,ZrMn2 合金的主相结构转变为C15型Laves相 ,表明Ni为C15相稳定元素。对Zr Mn Ni三元合金 ,V为C14相稳定元素 ,而Co、Fe、Cu则为C15相稳定元素。取代量较少时 ,Cr为C15相稳定元素 ,取代量增加时 ,C15相稳定作用减弱。Ti元素为C14相稳定元素 ,Ti对Zr的部分取代将导致合金主相结构转变为C14型Laves相。合金化元素对ZrMn2 合金的相组成的影响与元素的电子浓度和原子尺寸不同有关     

快凝合金Zr（Ni0.55Mn0.3V0.1Cr0.05）2.1的相结构与储氢性能

在快冷（冷却速度１０＾５－１０＾６Ｋ／ｓ）Ｚｒ（Ｎｉ０．５５Ｍｎ０．３Ｖ０．１Ｃｒ０．０５）２．１合金中观察到一种高温条件下丰碑 纳米晶Ｃ１４Ｌａｖｅｓ相,其丰度随冷凝速度下降明显减少。     

DEGRADATION BEHAVIORS OF NEW TYPE TiV-BASED HYDROGEN STORAGE ELECTRODE ALLOYS

The degradation behaviors of the TiV-based multiphase hydrogen storage alloy Ti0.8,Zr0.2V3.2Mn0.64 Cr0.96Ni1.2 during electrochemical cycling in alkaline electrolyte have been studied by XRD, SEM, EIS and AES measurements. XRD analysis indicates that the alloy consists of a C14-type Laves phase and a V-based solid solution. The lattice parameters of both phases are increased after discharged with cycling, which indicates that more irreversible hydrogen remains not discharged in the alloy. It should be responsible for the decrease of discharge capacity. SEM micrographs show that after 10 electrochemical cycles, a large number of cracks can be observed in the alloy, existing mainly in the V-based solid solution phase. Moreover, after 30 cycles, the alloy particles are obviously pulverized due to the larger expansion and shrinkage of cell volumes during hydrogen absorption and desorption, which induces the fast degradation of the TiV-based hydrogen storage alloys. EIS and AES measurements indicate that some passive oxide film has been formed on the surface of alloy electrode, which has higher charge-transfer resistance, lower hydrogen diffusivity, and less electro-catalytic activity. Therefore it can be concluded that the pulverization and oxidation of the alloy are the main factors responsible for the fast degradation of the TiV-based hydrogen storage alloys.     

Ti基贮氢合金Ti0．3Zr0．225V0．25Mn0．3-xNi0．45＋x（x=0-0．25）的显微组织及电化学性能

为了改善Ti基贮氢合金的电化学性能，采用XRD，SEM及EDS分析了Ti0．3Zr0．225V0．25Mn0．3-xNi0．45＋x（x=，0．05，0．10，0．15，0．20，0．25）贮氢合金的相结构及相成分，并研究了合金的电化学性能。结果表明，合金均由六方结构的C14型Laves主相和立方结构的C15型Laves第二相构成；随着Ni替代量x的增大，合金的活化性能降低，而循环稳定性得到一定程度的改善。当Ni替代量x=0．05时，合金的放电容量达到最大，为426mAh／g，显示出很大的应用潜力.     

Ti掺杂ZrV2合金的相组成及贮氢性能研究

利用真空感应熔炼的方法制备出(ZrTi)V2合金,在950℃下对合金进行长时间的退火处理,对合金的相结构及吸氢性能进行测试。结果表明:(ZrTi)V2合金主要由C15Laves相、α-Zr相、Zr3V3O相和V基固溶体相组成,热处理使得α-Zr相及V基固溶体相减少;该合金经400℃,1h除气之后,再经过一次吸放氢循环即可达到最佳的活化效果;根据Van’tHoff关系外推出室温下该合金的平衡压力为8.1×10-14Pa。     

Pulverization mechanism of the multiphase Ti–V-based hydrogen storage electrode alloy during charge/discharge cycling

Pulverization is an important key factor for the electrochemical cycle stability of many hydrogen storage alloys. In this paper, the pulverization mechanism of the multiphase Ti–V-based hydrogen storage alloy which mainly consists of a V-based solid solution phase with the BCC structure and a C14 Laves phase is studied based on a sample material of the Ti_0.8Zr_0.2V_2.7Mn_0.5Cr_0.6Ni_1.25Fe_0.2 alloy. The microstructure of the alloy and the morphology change of the alloy electrode during the charge/discharge process were observed by transmission electron microscope, scanning electron microscope and atomic force microscope, etc. The effect of mechanical properties of the V-based phase and the C14 Laves phase on the pulverization behavior of the Ti–V-based alloy is discussed. The results show that microcracks initially occur at the phase boundary of the V-based phase and the C14 Laves phase and then extend to the C14 Laves phase in the charge/discharge process. The phase boundary is composed of a Ti segregated amorphous layer with a thickness of about 90 nm, mismatching with the crystallized V-base phase and C14 Laves phase. The toughness of the C14 Laves phase is much lower and the hardness is higher than that of the V-based phase. The weak bonding strength of the phase boundary, the lower toughness of the C14 Laves phase and the large volume expansion/contraction of the C14 Laves phase during charge/discharge cycling are the main factors that cause the pulverization of the Ti–V-based alloy.