CuxAlO2(0.92≤x≤1.0)陶瓷电输运性能

使用高温固相烧结法制备不同化学剂量比的CuAlO2陶瓷,研究CuxAlO2(0.92≤x≤1.0)中Cu、Al摩尔比的相对变化对其结构和导电性能的影响.结果表明:CuxAlO2(0.92≤x≤1.0)陶瓷片的结构和密度随着x值的增大,样品的结晶性逐渐变好,密度也逐渐增大,在x为0.98时,得到密度最大(5.02 g/cm3)且结晶良好的纯相CuAlO2;样品的光学带隙均约为3.44 eV;随着x值的增加,室温电导率先增大然后减小,在x为0.98时得到最大电导率为8.03×10-3 S/cm;电导率随温度的升高而显著增大,且曲线在100～300 K之间很好地符合Arrhenius关系,x为0.98时激活能最低,仅为0.085 eV;在所研究的成分范围内,CuAlO2陶瓷的导电能力主要取决于陶瓷片的致密度.     

MAGNETOSTRICTION IN ANTIFERROMAGNETIC Fe1-xMnx (0.30 ≤ x ≤ 0.55) ALLOYS

采用真空感应熔炼法,制备Fe1-xMnx(x=O.30,0.35,0.40,0.50,0.55(原子分数))合金,在1000℃保温24h,炉冷至室温.研究了不同结构Fe1-xMnx合金样品的室温磁致伸缩性能.结果表明,x≤0.40时,Fe1-xMnx合金样品为,γ ε双相结构,并且ε相体积分数随Mn含量增加而减小,磁致伸缩性能较差;x>0.40时,合金样品为单一的γ相,具有良好的磁致伸缩性能.Fe0.50Mn0.50合金样品在1.9T磁场中的磁致伸缩可达8.73x 10-4     

Sm_（1＋x）Ba_（2－x）Cu_3O_y（0≤x≤0．4）的热力学稳定性

用测量固体电解质电池电动势（ＥＭＦ）的方法，测试了Ｓｍ－Ｂａ－Ｃｕ－Ｏ体系主要化合物的标准Ｇｉｂｂｓ生成自由能；结果发现，稀土复合氧化物Ｓｍ_（１＋ｘ）Ｂａ_（２－ｘ）Ｃｕ_３Ｏ_ｙ，随着固溶度ｘ增加，化合物稳定性下降ＤＴＡ实验支持这一结论。     

Structural,Optical, and Ferroelectric Behaviors of Cul-xLixO （0≤ x ≤ 0.09） Nanostructures

We report structural, optical, and ferroelectric behaviors of lithium-doped copper oxide （CU1-xLixO with x = 0.0, 0.05, 0.07, and 0.09） nanostructures synthesized by hydrothermal method. The XRD pattern indicates the pure phase formation of CuO without any impurity, and the crystallite size is found to be increases for x = 0-0.07 and decreases for x = 0.09. FESEM analysis shows that the average size of Cul xLixO nanostructures increases with the increasing the Li-doping concentrations up to 7% and then decreases for 9% Li doping concentration. Moreover, Raman and photoluminescence spectrum also confirm the phase formation of CuO. A significant reduction in optical band gap is observed up to x = 0.07, and then band gap increases for x ~ 0.09 due to segregation of the impurities on the surface or grain boundaries, which may suppress the grain growth and results the enhancement in optical band gap. Moreover, a weak ferroelectricity is observed in CuO nanostructures for pure and 9% Li doping through polarization versus electric field （P- E）.     

Theoretical analysis of β-LaNi5Hx（5≤x≤8）： structure and energetics

The calculations of total energy, band structure, and electronic density of states and Mulliken population analysis of β-LaNi5Hx（5≤x≤8） were performed by adopting the method of total energy based on the density functional theory. The augmented plane wave function was selected as the basis set in combination with ultra-soft pseudo-potential technology. The influence of the amount of H absorbed in alloys was discussed in terms of geometry, electronic structure and thermodynamic derived from calculated results. The results show that the amount of H absorbed and the preferred site occupation of the absorbed hydrogen atoms were controlled by the position of H- bands and the energy gap between H-bands and conduction bands. The β-phase hydrides of LaNi5 are most stable when hydrogen atom capacity coating in the range of 6 ～ 7.     

CuCr_(1-x)Mg_xO_2(0≤x≤0.09)薄膜的光电性能

采用射频磁控溅射方法,在石英衬底上制备Mg掺杂的CuCrO2薄膜。通过XRD、紫外吸收光谱及电学性能的测量表征该系列薄膜样品的结构与光电性能。结果表明:退火处理后所有薄膜样品的结晶性良好,均为3R型铜铁矿结构;薄膜的电导率随掺杂量的增加而增大。当x=0.09时,样品的室温电导率可达6.16×10-2S/cm,比未掺杂的CuCrO2提高近400倍,且霍耳测试表明所制备的薄膜为p型导电体。电导率随温度变化关系表明:薄膜样品在200～300K的温度范围内均很好地符合Arrhenius热激活规律;当x=0.09时,最低激活能仅为0.034eV。薄膜的可见光透过率与光学带隙宽度均随掺杂量的增加而减小。     

La（1＋x）／3Ba（2—x）／3MnxCu1—xO3（0.8≤x≤1）晶体结构和？…

用固态反应法制备了名义组分为Ｌａ（１＋ｘ）／３Ｂａ（２－ｘ）／３ＭｎｘＣｕ１－ｘＯ３（０．８≤ｘ≤１）的系列试样。试样结构的单相性经粉末Ｘ射线衍射分析而得以证实,且随Ｃｕ的掺杂其结构由未掺杂时的立方对称性转变为正交对称性。输运实验表明：所有试样均经历了半导体到金属的转变但转变温度ＴＰ随掺杂量增加而逐渐移向低温端;外加磁场大大增加了ＴＰ附近的导电性,导致ＴＰ附近最大磁电阻效应的出现。     

THERMODYNAMIC STABILITY OF COMPLEX OXIDE Sm_(1+x)Ba_(2-x)Cu_3O_y(0≤x≤0.4)

用测量固体电解质电池电动势的方法，测试了Ｓｍ－Ｂａ－Ｃｕ－Ｏ体系主要化合物的标准Ｇｉｂｂｓ生成自由能；结果发现稀土复合氧化物Ｓｍ１＋ｘＢａ２－ｘＣｕ３Ｏｙ随着固溶度ｘ增加。化合物稳定性下降。ＤＴＡ实验支持这一结论。     

Ce1-xNdxO2-x/2(0≤x≤0.6)纳米粉体的低温燃烧合成

采用低温燃烧合成法,在柠檬酸-硝酸盐体系中合成了Ce1-xNdxO2-x／2（0≤x≤0.6）固溶体纳米粉体．X射线衍射（XRD）结果表明,Nd^3＋取代Ce^4＋形成具有单相立方萤石结构的固溶体,其晶格常数随Nd^3＋掺杂浓度的增大而线性增加,晶粒尺寸在15-24am之间．透射电镜（TEM）结果表明,粉体颗粒尺寸在2m-40am之间,分散性较好,具有较高的烧结活性．Raman光谱结果表明,F2g宽化峰的出现与掺杂后固溶体中产生的氧空位有关,并且随着掺杂浓度的增加,氧空位数量也随之增加．X射线荧光光谱（XRF）的分析表明,实际掺杂浓度非常接近原始化学计量比．     

Synthesis of CaNi1−xPdx (0.1≤x≤1) alloys and hydrogenation properties of CaPd

An evaluation of the substitution of a third element for the constituent elements (Ca, Ni) in the compound was conducted in order to obtain information about stabilization of the CaNi compound which does not exist as a stable phase. Prior to the experimental study of the substitution, the candidates for the third element were investigated using Miedema’s semi-empirical model, from the standpoint of formation enthalpy, and as a result, Pd was chosen as the element to stabilize the compound. The samples with the nominal compositions of CaNi_1−xPd_x (0.1≤x≤1) were prepared by sintering and high frequency heating, and the constituent phases and hydrogenation properties were examined. New ternary phases such as Ca₁(Ni, Pd)₁ were not obtained under the present conditions; however, some pieces of new information such as the substitution of Ni for Pd in CaPd₂ and reversible hydrogenation of CaPd at 373 K were obtained through the studies.     

正交Li1-xMnO2(0≤x≤0.95)首次充电过程中物相及结构的演变

用高精度非原位XRD结合Rietveld精修对正交Li1-xMnO2(简写为o-Li1-xMnO2,0≤x≤0.95)在首次充电(电化学脱锂)过程中物相及结构的演变进行了研究。结果表明,o-LiMnO2电极的电压升高速率与其结构的变化有关;随着电化学脱锂o-LiMnO2发生一系列相变。证实了文献的理论计算和由晶体学推测出的相变过程,即相变产物中先后出现岩盐型锰酸锂和类尖晶石型锰酸锂。相变结束后,产物中只有岩盐型和类尖晶石锰酸锂2种物相。随着充电的进行,都有Li+从岩盐型和类尖晶石锰酸锂晶格中脱出,二者晶胞参数逐渐变小,微结构也不断变化。     

铜模喷铸Fe_(100-x)Ga_x(15≤x≤30)合金的磁致伸缩

采用铜模喷铸法,制备Fe100-xGax(x=15,19,23,27.5,30)合金。实验结果表明铜模喷铸有利于改善低Ga(15≤x<23)Fe100-xGax合金的磁致伸缩,却大幅降低了高Ga(23≤x≤30)Fe100-xGax合金的磁致伸缩。以Fe81Ga19和Fe72.5Ga27.5合金为例,喷铸态Fe81Ga19样品的饱和磁致伸缩比800℃淬火态提高了7%;而喷铸态Fe72.5Ga27.5样品的饱和磁致伸缩为6.1×10-5,仅是800℃淬火态的60.4%。此外,淬火态Fe72.5Ga27.5样品的饱和磁化强度为131.21A·m2·kg-1,也高于喷铸态(126.21A·m2·kg-1)。     

Sb掺杂Mg_(2-x)Zn_xSi(0≤x≤0.1)固溶体的热电性能（英文）

利用B_2O_3助熔剂法结合SPS技术制备了Mg_(2-x)Zn_xSi_(0.99)Sb_(0.01)(0≤x≤0.1)固溶体。测量了300~780 K温度区间内试样的电导率、塞贝克系数和热导率。发现晶格热导率随Zn取代量的增大而降低。而电导率随Zn取代量的增大而先降低后增大。讨论了影响电导率与晶格热导率的变化规律的具体内在机制。所有样品中x=0.075样品的功率因子最高,在780 K达1.76 m W·m~(-1)·K~(-2),比基体Mg_(2-x)Zn_xSi_(0.99)Sb_(0.01)高约18%。x=0.1样品具有最低晶格热导率,在770 K达到2.86 W·m~(-1)·K~(-1)。低晶格热导率使Mg_(1.9)Zn_(0.1)Si_(0.99)Sb_(0.01)具有最高热电优值,在780 K达0.37。     

配合物燃烧法合成钙钛矿型化合物Gd1-xCaxCrO3(0.1≤x≤0.4)及其电学性能

以配合物燃烧法合成了Ca2+取代的铬酸钆Gd1-xCaxCrO3,在0.1≤x≤0.3时获得纯钙钛矿相,其晶胞体积随Ca含量增加而减小,x≥0.4时,出现第二相.粉体粒径为20nm～50nm,具有高的烧结活性,1400℃烧结4h,其相对密度达到94.8%.在Ca掺杂量小于0.3时(x=0.1,0.2,0.3),相对密度和电导率皆随Ca含量增加而增大,与常用的铬酸镧相比,Gd0.7Ca0.3CrO3电导率高,在700℃可达24 Scn-1(相对密度94%),能适于用做中温固体氧化物燃料电池的连接材料.     

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…     

Structural,Optical, and Ferroelectric Behaviors of Cu_(1-x)Li_xO(0≤x≤0.09) Nanostructures

We report structural,optical,and ferroelectric behaviors of lithium-doped copper oxide(Cu1-xLixO with x =0.0,0.05,0.07,and 0.09) nanostructures synthesized by hydrothermal method.The XRD pattern indicates the pure phase formation of CuO without any impurity,and the crystallite size is found to be increases for x =0–0.07 and decreases for x =0.09.FESEM analysis shows that the average size of Cu1-xLixO nanostructures increases with the increasing the Li-doping concentrations up to 7% and then decreases for 9% Li doping concentration.Moreover,Raman and photoluminescence spectrum also confirm the phase formation of CuO.A significant reduction in optical band gap is observed up to x =0.07,and then band gap increases for x =0.09 due to segregation of the impurities on the surface or grain boundaries,which may suppress the grain growth and results the enhancement in optical band gap.Moreover,a weak ferroelectricity is observed in CuO nanostructures for pure and 9% Li doping through polarization versus electric field(P–E).     

Effects of Mn Content on Mechanical Properties of FeCoCrNiMn_x (0≤x≤0.3) High-Entropy Alloys: A First-Principles Study

Effects of Mn content on mechanical properties of FeCoCrNiMn_x(0 ≤x≤0.3) high-entropy alloys(HEAs) are investigated via first-prmciples calculations combining EMTO-CPA method.Related physical parameters,including lattice constant.elastic constants,elastic modulus,Pugh's ratio,anisotropy factors,Poisson's ratio,Cauchy pressure,Vickers hardness,yield strength,and energy factor,are calculated as a function of Mn content.The results show that the resistances to bulk,elastic,and shear deformation decrease with increasing Mn content.Pugh's ratio B/G indicates that the ductility of FeCoCrNiMn_x HEAs has a remarkable reduction between 22 and 24% of Mn content.Meanwhile,Cauchy pressure suggests that the atomic bonding transforms from metallic to directional characteristic from 22 to 24% of Mn content.Vickers hardness and yield strength of FeCoCrNiMn HEA are intrinsically larger than those of FeCoCrNi HEA.Dislocation nucleation easily occurs in FeCoCrNiMn HE A compared to FeCoCrNi HEA,and large dislocation width in FeCoCrNiMnO_2 HE A results in low stacking-fault energy,which easily induces twinning deformation.This work provides a valuable msieht for further theoretical and experimental study on the mechanical properties of FeCoCrNiMn_x(0≤x≤0.3) HEAs.     

NASICON型电解质材料Li_(1+x)Er_xZr_(2-x)(PO_4)_3(0.1≤x≤0.2)的制备与性能

以Li_2CO_3、ZrO_2、Er_2O_3、(NH_4)_2HPO_4为初始原料,采用传统的固相法合成了Li Zr_2(PO_4)_3基NASICON型固态电解质材料Li_(1+x)Er_xZr_(2-x)(PO_4)_3(x=0~0.2)。通过无压烧结和放电等离子烧结法(SPS)烧结得到致密的电解质片,采用无压烧结过程中在样品中加入少许的PVA使得样品烧结致密。利用XRD、SEM、EIS分别测得样品的结构、形貌以及电性能。结果表明:通过SPS烧结的样品致密度可以达到92.6%。使用SPS烧结后的样品Li1.15Er0.15Zr1.85(PO_4)_3在常温下的晶粒和总电导率分别为2.2×10~(-4)和8.8×10~(-6) S·cm~(-1)。样品的激活能为0.36 e V。     

Crystal structure, 57Fe Mössbauer spectroscopy and magnetization of UxFe6Sn6 (0≤x≤0.6)

The U_xFe₆Sn₆ (0≤x≤0.6) intermetallics were prepared as polycrystalline samples by arc melting followed by annealing. They crystallize in the P6/mmm space group as a lacunary variant of the HfFe₆Ge₆-type, with an ordered insertion of U within the Sn₈ voids of the FeSn framework, and are isostructural with the R_xFe₆Sn₆ compounds (R=Sc, Zr, Tm, Yb, Lu). ⁵⁷Fe Mössbauer spectroscopy shows that the Fe magnetic moments, μ_Fe, are already ordered at room temperature. Anisotropic contributions to the total hyperfine field at the Fe site indicates that μ_Fe are perpendicular to the crystallographic c axis in contrast to the Sc, Zr and rare-earth (except Yb) containing compounds, where μ_Fe are directed along the c axis. The values deduced for the angles between the main axes of the electric field gradient and μ_Fe further show that, within each (001) plane, μ_Fe have a ferromagnetic arrangement similar to that in FeSn and Yb_0.6Fe₆Sn₆. In U_xFe₆Sn₆, the hyperfine fields increase with U content. Magnetization data in the 2–300 K show small ferromagnetic components for the U_0.4Fe₆Sn₆ and U_0.6Fe₆Sn₆ compositions.     

La_((1+x)/3)Ba_((2-x)/3)Mn_xCu_(1-x)O_3(0.8≤x≤1)晶体结构和输运性质

用固态反应法制备了名义组分为 L a(1 + x) /3Ba(2 - x) /3Mnx Cu1 - x O3(0 .8≤ x≤ 1) 的系列试样。试样结构的单相性经粉末 X射线衍射分析而得以证实 ,且随 Cu的掺杂其结构由未掺杂时的立方对称性转变为正交对称性。输运实验表明 :所有试样均经历了半导体到金属的转变 ,但转变温度 TP随掺杂量增加而逐渐移向低温端 ;外加磁场大大增加了 TP附近的导电性 ,导致 TP附近最大磁电阻效应的出现