(La_xNd_y)_(0.90)Mg_(0.10)Ni_(3.09)Mn_(0.12)Co_(0.60)Al_(0.13)贮氢合金自放电性能研究

为了提高La-Mg-Ni基贮氢合金的荷电保持率,本文研究了La/Nd比的变化对La-Mg-Ni基贮氢合金自放电性能的影响。随着Nd替代La量的增加,(LaxNdy)0.9Mg0.10Ni3.09Mn0.12Co0.60Al0.13(x/y=5,4,3,2,1)合金的荷电保持率先增大后减小,当x/y=4时,其荷电保持率达到最大值80.8%(318 K)。合金电极贮存后,FESEM-EDS和XRD分析表明,合金颗粒表面形成了Mg(OH)2和Nd(OH)3。P-C-T曲线和Tafel极化测试表明,随着Nd含量的增加,金属氢化物的稳定性呈现先增加后降低和腐蚀电流先减小后增大的规律。     

(Fe_(0.86)Zr_(0.033)Nb_(0.033)B_(0.068)Cu_(0.01))_x(Al_2O_3)_(1-x)颗粒膜的霍耳效应

用磁控溅射方法制备了系列 (Fe0 .86 Zr0 .0 33Nb0 .0 33B0 .0 6 8Cu0 .0 1 ) x(Al2 O3) 1 -x颗粒膜样品 ,体积百分比x从 0 .3 3～ 0 .63 ,样品厚度约为10 0nm。室温下在Fe0 .86 Zr0 .0 33Nb0 .0 33B0 .0 6 8Cu0 .0 1 体积百分比x =0 .43时得到 17.5 μΩ·cm的最大饱和霍耳电阻率 ,比纯铁磁金属提高了 3～ 4个量级。对其磁性和微结构进行了研究 ,样品霍耳电阻率随外场的变化曲线 ρxy～H与磁场平行于膜面时的磁化曲线M～H有相似性 ,说明霍尔电阻率 ρxy与磁化强度M相关。样品电阻率 ρxx随金属体积百分比x的减小而增加 ,在x =0 .43附近发生突变 ,从金属导电变为绝缘体。根据微结构和输运性质对可能的机制进行了探讨     

Indentation creep behaviors of Mg61Cu28Gd11 and （Mg61Cu28Gd11）99.5Sb0.5 bulk metallic glasses at room temperature

The room temperature creep behaviors of Mg61Cu28Gd11 and(Mg61Cu28Gd11)99.5Sb0.5 bulk metallic glasses(BMGs) were revealed by means of nanoindentation technique.The creep mechanism was explored by characterization of creep rate sensitivity,creep compliance and retardation spectra.The results showed that the experimental creep curves could be well described by a generalized Kelvin model.The low creep rate sensitivity of both Mg-based BMGs indicated that their room temperature creep was dominated by localized shear flow.In addition,the(Mg61Cu28Gd11)99.5Sb0.5 glassy alloy exhibited lower creep rate sensitivity,creep compliance and milder retardation peak,indicating its higher creep-resistance and less relaxed state.Furthermore,the creep retardation spectrum consisted of two relatively separated peaks with the well defined characteristic relaxation times.     

La_(1.1)Fe_(11.4)Si_(1.55)Ge_(0.05)合金的磁热效应

使用电弧熔炼法制备了La1.1Fe11.4Si1.55Ge0.05合金。研究了用少量的Ge替代Si后,La1.1Fe11.4Si1.55Ge0.05合金的磁性和磁热效应。粉末X射线衍射结果表明:在1273K真空退火处理10d后,合金La1.1Fe11.4Si1.55Ge0.05主相为NaZn13型立方结构,存在微量的α-Fe相。热磁曲线M-T与Arrott曲线表明:在居里温度Tc=205K处发生由铁磁性(TTc)转变为顺磁性(TTc)的二级磁相变。在磁场变化0～1.5T下,根据等温磁化曲线通过Maxwell关系式计算得出最大磁熵变-ΔSmmax=9J.kg-.1K-1。Ge替代Si后该合金在其居里温度Tc处-ΔSm-T曲线半高宽增大,使合金的相对制冷能力RCP(S)有所提高。     

Structure and Magnetic Properties of Y(Fe_(1-x) Co_x)_ (11.3) Nb_(0.7)

ＩｎｒｅｃｅｎｔｙｅａｒｓＴｈＭｎ12 ｔｙｐｅｉｒｏｎ ｒｉｃｈｃｏｍｐｏｕｎｄｓｈａｖｅｂｅｅｎｉｎｔｅｎｓｉｖｅｌｙｉｎｖｅｓｔｉｇａｔｅｄｄｕｅｔｏｔｈｅｉｒｅｘｃｅｌｌｅｎｔｐｅｒｍａｎｅｎｔ ｍａｇｎｅｔｉｃｐｒｏｐｅｒｔｉｅｓ .ＡｌｔｈｏｕｇｈｐｕｒｅｂｉｎａｒｙＲＥ Ｆｅｃｏｍ ｐｏｕｎｄｓｄｏｎｏｔｅｘｉｓｔ,ｔｈｅＴｈＭｎ12 ｓｔｒｕｃｔｕｒｅｃａｎｂｅｓｔａｂｉｌｉｚｅｄｉｎｐｓｅｕｄｏｂｉｎａｒｉｅｓｏｆｔｈｅｔｙｐｅＲＥＦｅ12 -ｘＭｘ,ｗｉｔｈＭ =Ａｌ,Ｔｉ,Ｃｒ ,Ｓｉ ,Ｍｏ ,Ｖ …     

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...     

Magnetocaloric effect and magnetic properties of La_（0.9）Ce_（0.1）（Fe_（0.99）Mn_（0.01））_（11.6）Si_（1.4）H_（1.6） compound

Magnetocaloric effect and magnetic properties of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 and its hydride La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 were investigated. The Curie temperature of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was increased by hydrogen absorption. XRD patterns showed that the structure of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 remained NaZn13-type. The Curie temperature (TC) of the sample was increased from 174 K to 331 K. The homogeneity of the hydrogen absorption for La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 was proven very well by the random measurement of DSC. The magnetic entropy △SM of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 had peak at 326 K. The peak value of-△SM-was 12.3 and 7.8 J/(kg.K) under magnetic field change of 0-2 T and 0-1 T,respectively,which was comparable with Gd5Si2Ge2. The negative slope and inflection point of the Arrott curve indicated that the first-order magnetic transition of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was reserved after hydrogen absorption.