Crystal Structures of Dy_2(WO_4)_3 and GdY(WO_4)_3

Two compounds, Dy2(WO4)3 and GdY(WO4)3, were synthesized by using the standard solid state reaction technique. The crystal structure was determined by powder X-ray diffraction and Rietveld refinement method. It is found that both compounds have Eu2(WO4)3-type monoclinic structure, with space group C 2/c, Z = 4. The unit cell parameters of Dy2(WO4)3 are a = 0.75981(1) nm. b = 1.13220( 1) nm, c = 1.13254( 1) nm, and β= 109.8001(3)°, and those of GdY(WO4)3 are a = 0.76175(1) nm, b = 1.13543(1) nm, c = 1.13496(2) nm, and bbbbbbbbbβwhile each rare-earth atom is surrounded by eight oxygen atoms. WO4 tetrahedra share their four vertices with REO8 (RE = Dy, Gd, or Y) trigondodecahedra and some REO8 trigondodecahedra share an edge with each other. The phase transition and the magnetic properties were investigated by differential thermal analysis (DTA) and dc superconducting quantum interference device (SQUID) magnetometer.     

Crystal structure determination of CoGeTe from powder diffraction data

The crystal structure of cobalt germanium telluride CoGeTe has been determined by direct methods using integrate intensities of conventional X-ray powder diffraction data and subsequently refined with the Rietveld method. The title compound was prepared by heating of stoichiometric amount of Co, Ge and Te in silica glass tube at 670 °C.CoGeTe adopts orthorhombic symmetry, space group Pbca with unit cell parameters a = 6.1892(4) Å, b = 6.2285(4) Å, c = 11.1240(6) Å, V = 428.8(1) Å³ and Z = 8. Its crystal structure is formed by [CoGe₃Te₃] octahedra sharing both edges and corners. CoGeTe represents a ternary ordered variant of α-NiAs₂ type structure. An important feature present in CoGeTe is an occurrence of short Co–Co distance across the shared edge of [CoGe₃Te₃] octahedra. Differential thermal analysis (DTA) has revealed that CoGeTe melts incongruently at about 725 °C; CoGeTe decomposes into GeTe, CoGe and CoTe₂. Temperature dependence of the electrical conductivity and value of Seebeck coefficient at 300 K are also reported.     

UFeGa5单晶生长及晶体结构研究

采用镓自助熔剂的方法生长出了UFeGa5单晶,采用X射线衍射技术和Rietveld方法对UFeGa5晶体结构进行了研究。结果表明:生长出的UFeGa5单晶体结构完整,结晶性好。UFeGa5具有HoCoGa5型四方结构,空间群为P4/mmm(No.123),其晶格常数为a=0.42533(2)nm,c=0.67298(3)nm,并得到了透射电镜(TEM)实验验证。     

金诺芬的晶体结构研究

用X射线粉末衍射方法 (XRD)对 3种不同熔点的金诺芬 (C2 0 H34AuO9PS)的晶体结构进行研究。结果表明 ,熔点为 1 1 2～ 1 1 4℃的金诺芬属于单斜晶系 ,晶胞参数是a =1 0 30 6nm ,b =0 82 30nm ,c =1 61 62nm ,β =1 0 5 31 6° ;熔点为 1 1 8～ 1 2 0℃的金诺芬属于六方晶系 ,晶胞参数是a =1 462 4 ( 4 )nm ,c =1 1 367( 3)nm ,β =1 2 0° ;熔点为 1 1 4～ 1 1 8℃的金诺芬是单斜晶系和六方晶系晶体组成的混合物。     

X-ray Powder Diffraction Data and Crystal Structure of NiSbY

Ｘ－ｒａｙＰｏｗｄｅｒＤｉｆｆｒａｃｔｉｏｎＤａｔａａｎｄＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆＮｉＳｂＹＺｅｎｇＬｉｎｇｍｉｎ，ＬｉＪｕｎｑｉｎ，ＺｈａｎｇＬｉｐｉｎｇａｎｄＺｈｕａｎｇＹｉｎｇｈｏｎｇ（曾令民）（李均钦）（张丽萍）（庄应烘）（Ｉｎｓ...     

Crystal structure of La5Ti4GaO17

The crystal structure of La₅Ti₄GaO₁₇ compound synthesized by heat-treatment of the co-precipitated hydroxy-oxalates has been determined by the X-ray powder diffraction. It was found that crystal structure of La₅Ti₄GaO₁₇ belongs to the CaLa₄Ti₅O₁₇-type structure (space group Pmnn, a = 0.3912(1) nm, b = 3.128(1) nm, c = 0.5523(1) nm, Z = 2). The final R_W value is equal to 0.081 for 169 independent reflections.     

The ternary iron aluminum carbides

Carbides present in ternary Fe-Al-C were investigated by the combined utilization of an X-ray diffractometer and a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. The alloys were prepared by arc melting and the microstructure was homogenised by a solution annealing treatment in the temperature range 950-1050 °C for 15 min. The diffraction patterns of resulting materials were analysed using a multiphase Rietveld refinement. The steel is composed of a ferritic matrix with carbides Fe₃C, M₂₃C₆, and/or κ-Fe₃AlC depending on the Al and C concentration. It is the first time that the existence of M₂₃C₆ ternary carbide in the Fe-Al-C system is recognized. Microprobe analyses performed revealed that the solubility of Al in M₂₃C₆ is low, with an Fe/Al ratio (in at.%) higher than 15. On the other hand, the amount of Al in the cementite is negligible and hence its lattice parameters do not depend on the Al concentration of the alloy.     

CRYSTAL STRUCTURE AND X-RAY POWDER DIFFRACTION DATA FOR RE COMPOUND HoNiSb

ＣＲＹＳＴＡＬＳＴＲＵＣＴＵＲＥＡＮＤＸ－ＲＡＹＰＯＷＤＥＲＤＩＦＦＲＡＣＴＩＯＮＤＡＴＡＦＯＲＲＥＣＯＭＰＯＵＮＤＨｏＮｉＳｂ￥Ｚｅｎｇ，Ｌｉｎｇｍｉｎ；Ｌｉ，Ｊｕｎｇｑｉｎ；Ｚｈａｎｇ，Ｌｉｐｉｎｇ；Ｚｈｕａｎｇ，Ｙｉｎｇｈｏｎｇ；Ｈａｏ，Ｊｉａ...     

X RAY POWDER DIFFRACTION DATA AND STRUCTURE REFINEMENT OF COMPOUND ErNi 2Si 2

１ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｒａｒｅｅａｒｔｈｃｏｍｐｏｕｎｄｓＲＥＴ２Ｓｉ２,ｗｈｅｒｅＲＥｉｓａｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔａｎｄＴｉｓａｔｒａｎｓｉｔｉｏｎｍｅｔａｌｅｌｅｍｅｎｔ,ｈａｖｅｂｅｅｎｓｔｕｄｉｅｄｗｉｔｈｇｒｅａｔｉｎ?..     

A modified Rietveld method to model highly anisotropic ceramics

High energy X-ray diffraction was employed to probe the complex constitutive behavior of a polycrystalline ferroelectric material in various sample orientations. Pb(Zn,Nb)O₃-Pb(Zr,Ti)O₃ (PZN-PZT) ceramics were subjected to a cyclic bipolar electric field while diffraction patterns were taken. Using transmission geometry and a two-dimensional detector, lattice strain and texture evolution (domain switching) were measured in multiple sample directions simultaneously. In addition, texture analysis suggests that non-180° domain switching is coupled with lattice strain evolution during uniaxial electrical loading. As a result of this material’s high strain anisotropy, the full-pattern Rietveld method was inadequate to analyze the diffraction data. Instead, a modified Rietveld method, which includes an elastic anisotropy term, yielded significant improvements in the data analysis results.     

X-RAY RIETVELD STRUCTURE REFINEMENT OF ErNiSb

ＸＲＡＹＲＩＥＴＶＥＬＤＳＴＲＵＣＴＵＲＥＲＥＦＩＮＥＭＥＮＴＯＦＥｒＮｉＳｂ①ＺｅｎｇＬｉｎｇｍｉｎ,ＹａｎＪｉａｌｉｎ,ＯｕＸｉａｎｇｌｉ,ＨｅＷｅｉａｎｄＺｈｕａｎｇＹｉｎｇｈｏｎｇＩｎｓｔｉｔｕｔｅｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅ,Ｇ...     

Mo-Nb合金单晶晶向测定和表征

采用一种金相和RO-XRD相结合的方法,快速、准确地测定Mo-Nb合金单晶的晶向,并对晶向品质做出精确的表征。所测Mo合金单晶,其(111)晶面衍射角的测试值与计算值基本一致,其晶向偏离角分别为0.73o和0.91o,与电子背散射衍射法测试的结果一致,晶向分散度仅为1o左右。     

Effect of A site and B site doping on structural, thermal, and dielectric properties of BiFeO3 ceramics

Polycrystalline Bi_1−xBa_xFe_1−yM_yO₃ (M = Co and Mn; x = 0.1, y = 0.1) were synthesized by solid-state route method to study the compositional driven structural transformations in multiferroics. Room temperature X-ray diffraction patterns confirmed the formation of perovskite structure. Rietveld-refined crystal structure parameters revealed the existence of rhombohedral R3c symmetry for both the samples. The samples were found to be nearly free from any other secondary phases. Raman analysis reveals that Ba atom substitutes Bi site and Mn and Co atom substitutes Fe site into the BiFeO₃ with the shifting of phonon modes. The red shift is attributed to Co or Mn doping where as blue shift occurs from Ba doping. The differential scanning calorimetry reveals the corresponding Neel temperature 370 °C and 326 °C for Co and Mn doped samples. Ba and Co substitution with x = 0.1 and y = 0.1 has not affected the Neel temperature of the parent BiFeO₃ as well of Ba and Mn substitution. The variation of frequency dispersion in permittivity and loss pattern due to A-site and B-site substitution in BiFeO₃ was observed in the dielectric response curve.     

Zr—Mn—Ni系Laves相贮氢合金中的Zr—Ni相及其晶体结构研究

采用Ｘ射线粉末衍射和Ｒｉｅｔｖｅｌｄ全谱拟事分析,详细地研究了Ｚｒ（Ｍｎ１－ｘＮｉｘ）２（ｘ＝０．４０～０．７５）三元Ｌａｖｅｓ相贮氢合金中形成Ｚｒ－Ｎｉ相的类型及其晶体结构。实验结果表明：Ｚｒ－Ｍｎ－Ｎｉ合金中出现的Ｚ４－Ｍｎ－Ｎｉ合金中出现的Ｚｒ－Ｎｉ相包括ＺｒＮｉ、Ｚｒ９Ｎｉ１１和Ｚｒ７Ｎｉ１０３类,ｒ－Ｎｉ相类型与合金中的Ｎｉ含量有关。其中,ＺｒＮｉ相在ｘ＝０．４０～０．５０范围内出现,Ｚ     

Crystal growth and structure of La3MGa5O14 (M=Ti, Zr, Hf)

La₃M⁴⁺Ga₅O₁₄ (M=Ti, Zr, Hf) compounds were crystallized using the micro-pulling down and Czochralski techniques. Both growth methods showed that these three crystals are peritectic compounds. The structure of La₃TiGa₅O₁₄ (LTiG) crystal was refined using single-crystal X-ray diffraction data. LTiG was observed to be isostructural to Ca₃Ga₂Ge₄O₁₄ (P321 (No.150), Z=1) and the lattice parameters are a=8.223(1), c=5.109(1) Å. The Ti atoms were found to occupy octahedral (1a) and tetrahedral (3f) sites coordinated by six and four oxygen atoms, respectively.     

单晶结构残余应力的X射线衍射分析技术

准确测定单晶材料残余应力是控制和调整单晶构件中残余应力的前提。基于弹性力学对单晶材料弹性模量与对应衍射晶面的关系进行理论分析,建立立方单晶材料的残余应力分析模型,并提出具体试验方法,以DD3单晶叶片为例,进行试验验证。结果表明：不同衍射晶面的弹性模量受独立弹性柔度系数、取向系数影响,DD3单晶叶片表面应力模型计算值与实测值间相对误差在20 MPa范围内。这种X射线衍射残余应力测定方法测定的残余应力值可靠性较高,为工程应用中测定立方单晶残余应力提供了理论依据和试验基础。     

Zr—Mn—V—Ni储氢电极合金中Zr—Ni相形成及其晶体结构研究

Ｚｒ（Ｍｎ０．４５－ｘＮｉ０．５５Ｖｘ）２（ｘ＝０．０５～０．４０）Ｌａｖｅｓ相储氢合金中的Ｚｒ－Ｎｉ相类型主要有ＺｒＮｉ和Ｚｒ９Ｎｉ１１相。ＺｒＮｉ１１相在整个研究的成分范围内出现,而 ＺｒＮｉ相仅在ｘ＝０．２０－０．４０范围内出现。Ｚｒ９Ｎｉ１１相的含量与合金中的 Ｍｎ、Ｖ含量关系不大,而ＺｒＮｉ相的含量随合金中的Ｍｎ、Ｖ含量变化呈增加趋势。Ｚｒ９Ｎｉ１１和ＺｒＮｉ相的晶格常数随合金中的Ｍｎ、Ｖ含量变化而出现波动。Ｚｒ９Ｎｉ１１相为长程有序结构,有序堆垛方向为［１００］和［０１０］,同时ＺｒＮｉ１１相基本上被包围在Ｃ１５相中间,并与Ｃ１５相存在一定取向关系,Ｚｒ９Ｎｉ１１相的＜１１１＞晶向与Ｃ１５相的＜１１０＞晶向基本平行,两者的差值在２°～３°之间。     

Crystal Structure and X-ray Powder Diffraction Data for Rare Earth Compound PrNiSn

１ＩｎｔｒｏｄｕｃｔｉｏｎＴｅｒｎａｒｙｉｎｔｅｒｍｅｔａｌｉｃｃｏｍｐｏｕｎｄｓｃｏｎｔａｉｎｉｎｇｒａｒｅｅａｒｔｈｍｅｔａｌｓｈａｖｅｖａｒｉｏｕｓｃｒｙｓｔａｌｓｔｒｕｃｔｕｒｅｓａｎｄｍａｎｉｆｅｓｔｓｅｖｅｒａｌｉｎｔｅｒｅｓｔｉｎ...     

Crystal structures and hydrogenation behavior of （Ca0.9Sr0.08（Al1-xZnx）3 alloys

The crystal structures and hydrogenation behavior of the （Ca0.9Sr0.1）8（Al1-xZnx）3 （x = 0, 0.1, 0.2, 0.3 and 0.4） alloys were investigated. The new phase （Ca,Sr）E（Al,Zn） was found whenx 〉 0.1. （Ca, Sr）E（Al,Zn） crystallizes in space group 14/mmm （A-139）. The lattice parameters were calculated to be a = b = 1.1616（2） nm, c = 1.6422（4） nm. Zn atoms occupy the 8h and 16n sites together with Al atoms. The （Ca0.9Sr0.1）8Al3 alloy only contains a single Ca8Al3 phase. The （Ca0.9Sr0.1）8（Al1-xZnx）3 alloys consist of Ca8Al3, CasZn3, Ca and （Ca,Sr）2（Al,Zn） phases when x is from 0.1 to 0.3. As x increasing to 0.4, the alloy consists of （Ca,Sr）E（Al,Zn）, Ca8Zn3 and Ca. The hydrogenated （Ca0.9Sr0.1）8Al3 and （Ca0.9Sr0.1）8（Al0.9Zn0.1）3 samples consist of CartE and Al. The （Ca0.9Sr0.1）8（Al1-xZnx）3 （x = 0.2, 0.3 and 0.4） samples can be hydrogenated into CaH2, Al and CaZnl3 under a hydrogen pressure of 5 MPa at 473 K.     

Subsolidus phase relation in the system ZnO–Li2O–MoO3

The subsolidus phase relation of the system ZnO–Li₂O–MoO₃ has been investigated by X-ray diffraction (XRD) analyses. The phase diagram has been constructed. There are six binary compounds and one ternary compound in this system. The phase diagram comprises nine three-phase regions. The ternary compound Li₂Zn₂(MoO₄)₃ is refined by the Rietveld method. It belongs to an orthorhombic system with space group Pnma and lattice constants a = 5.1114 Å, b = 10.4906 Å, c = 17.6172 Å.