Icosahedral Al–Mn phases grown in diffusion-limited conditions

Sequential deposition of Mn on a polycrystalline Al layer at 523–573 K was found to result in an anomalous icosahedral (i) Al–Mn phase, characterized by alterations of intensity- and linewidth ratios. The anomalies suggest a non-equilibrium atom distribution, related to the limited diffusion of Al through the already-formed layer of i-AlMn. The activation energy of Al diffusion was inferred from X-ray diffraction (XRD) data taken for different deposition temperatures.     

A new metal-organic crystal: Potassium thiourea chloride

The growth and characterization of a new nonlinear metal-organic crystal, potassium thiourea chloride (PTC), is reported. The growth of single crystals of PTC was accomplished by the slow evaporation solution growth method. Single crystal X-ray diffraction analysis confirms the crystal structure. The FT-IR analysis confirms the presence of sulfur to potassium bonds in the complex. From the optical spectrum PTC has a good optical transmission in the entire visible region, which is an essential requirement for a nonlinear crystal.     

A new method to evaluate the quality of single crystal Cu by an X-ray diffraction butterfly pattern method

A new method for the evaluation of the quality of an Ohno continuous cast (OCC) Cu single crystal by X-ray diffraction (XRD) butterfly pattern was brought forward. Experimental results show that the growth direction of single crystal Cu is inclined from both sides of the single crystal Cu rod to the axis and is axially symmetric. The degree of deviation from the [100] orientation from the crystal axis is less than 5° with a casting speed 10–40 mm/min. The orientation of single crystal Cu does not have a fixed direction but is in a regular range. Moreover, the orientation of stray grains in the single crystal Cu is random from continuous casting.     

Effect of CuO addition in Bi-Sr-Ca-Cu-O and Y-Ba-Cu-O ceramics

The effect of adding CuO matrix to Bi_1·6Pb_0·4Sr₂Ca₂Cu₃O_δ and Y₁Ba₂Cu₃O_δ superconductors was investigated through resistivity, XRD, SEM, thermoelectric power (TEP), and ac magnetization studies. Samples with as low as 20% (by weight) of the superconducting phase showed superconducting transition in resistivity-temperature (R-T), with the superconducting zero around 77 K in thermoelectric power, critical current (J _c) values were evaluated by applying Bean’s critical state model. CuO could be added to the superconducting material without any significant deterioration in the quality of the samples, up to a concentration of as low as 40% (by weight) of the superconducting material.     

Microstructures and Morphology Evolution of Icosahedral Phase of As-cast Mg67.4Zn28.9Y3.7 Ternary Alloy Subjected to the Pouring Temperature

The microstructure,chemical composition and morphology evolution of icosahedral quasicrystalline phase of Mg67.4Zn28.9Y3.7 ternary alloy were investigated in detail at different pouring temperatures by X-ray diffraction(XRD),scanning electron microscopy(SEM) and energy-dispersive spectrum(EDS).Low interfacial energy favors the formation of I-phase.The experimental results show that the primary I-phase reveals petal-shaped with five and six branches,where each branch has facetted growth morphology with the s...     

一种测定晶体取向及其分布的简便XRD方法

提出了旋转定向测试法,其原理是使试样的在粉末X射线衍射仪上进行θ扫描的同时绕其端面法线自转,增加了晶面法线通过衍射平面的机会。通过这种方法可直观地区分取向多晶,准单晶或者单晶体,评定研制过程中准单晶和择优取向材料的晶体品质,确定单晶,准单晶及择优取向等材料的晶面相对宏观端面的晶向偏离角和取向分散度,还可对单晶体材料进行三维晶面定向。旋转定向法测试晶体取向具有快速简便,一机多用,精度高等优点,在电子、光学、磁性,机械等材料研究领域具在广泛的应用。     

Synthesis,structure and photocatalytic properties of <Emphasis Type="Italic">β</Emphasis>-ZrMo<Subscript>2</Subscript>O<Subscript>8</Subscript>

Monoclinic ZrMo₂O₈ was synthesized via solid state method and single crystals of the title compound have been grown by the hydrothermal method. The crystals belong to monoclinic crystal system with space group C2/c (No. 15) with a = 11·4243(19) Å, b = 7·9297(6) Å, c = 7·4610(14) Å and β = 122·15(2)°, Z = 4. The bandgap of the compound was 2·57 eV. Unlike the other polymorphs of ZrMo₂O₈, the monoclinic form has unique crystallographic features with ZrO₈ and Mo₂O₈ polyhedra. The photocatalytic activity of this compound has been investigated for the first time for the degradation of various dyes under UV irradiation and has been compared with the photoactivity of the trigonal form of ZrMo₂O₈. It has been observed that this compound exhibits specificity towards the degradation of cationic dyes.     

Crystal growth, thermal and optical studies on a metalorganic nonlinear optical material dipotassium boro maleate (DKBM)

A single crystal of dipotassium boro maleate (DKBM) was grown using slow evaporation method. The solubility of DKBM was determined for various temperatures. The structure of the grown crystal was confirmed by single crystal X-ray diffraction (SXRD) and powder X-ray diffraction (PXRD) techniques. The Fourier transform infrared (FT-IR) study reveals the various functional groups present in the grown crystal. The UV-Vis-NIR spectra revealed the transmission properties of the grown crystal. Thermal stability of the crystal was investigated using thermo gravimetric analysis (TGA) and differential thermal analysis (DTA). The nonlinear optical (NLO) property of the crystal was confirmed by powder second harmonic generation (SHG) test.     

添加剂对Y2Ti2O7陶瓷的微波介电性能的影响（英文）

研究了CrO3、Nb2O5、SiO2及Al2O3对Y2Ti2O7陶瓷的烧结性能、相组成和微波介电性能的影响.其中Nb2O5掺杂能够降低Y2Ti2O7陶瓷材料的烧结温度,提高基体陶瓷的介电常数和品质因子,引起谐振频率温度系数的明显变化.且随着Nb2O5含量的增多,所有样品的主晶相仍为立方烧绿石型Y2Ti2O7,Nb5+可能进入烧绿石结构中,部分取代Ti4+所在位置.实验结果表明:1mol%Nb2O5掺杂的陶瓷材料在1420℃下烧结致密,具有最佳的微波介电性能:εr=61.8,Q×f=9096GHz(f=5.494GHz),τf=54×10-6/℃.     

B2O3-Al2O3-SiO2透明玻璃陶瓷研究

玻璃陶瓷属于一类多晶陶瓷材料.通过调整玻璃基质和晶相组成可以制备出具有良好的力学、热学、电学和光学性能的玻璃陶瓷材料.采用传统的熔融和退火技术制备出含B2O3-Al2O3-SiO2-Li2O-K2O组分的硼铝硅玻璃,并通过成核和长晶工艺最终制备出透明玻璃陶瓷.配合料在铂金坩埚中于1450℃下熔融2h,然后经两步热处理制度控制晶核的生成和晶粒的长大.采用差热分析技术确定成核和长晶温度.采用X射线衍射技术对不同热处理制度下的玻璃陶瓷样品进行分析,以确定最佳成核和长晶条件.采用扫描电子显微镜分析玻璃陶瓷形态,晶粒尺寸及其在残余玻璃相中的分布.采用UV-Vis-Nir分光光度计测定玻璃陶瓷样品的透过率.     

Two new barium indium phosphates with intersecting tunnel structures: BaIn2P4O14, and Ba3In2P4O16

Two new barium indium phosphates BaIn₂P₄O₁₄ and Ba₃In₂P₄O₁₆ were synthesized by high temperature solution growth method and structurally characterized by single crystal X-ray diffraction analysis. They represent first compounds in the Ba-In-P-O systems. BaIn₂P₄O₁₄ and Ba₃In₂P₄O₁₆ display different types of 3D architectures. The projections of both structures concern about the existence of the intersecting tunnels. In compound BaIn₂P₄O₁₄, the tunnels are built up of the corner-sharing InO₆ octahedra and P₂O₇ groups, whereas in compound Ba₃In₂P₄O₁₆, they are formed by corner sharing of PO₄ tetrahedra and InO₆ octahedra. The electronic band structure calculations of two compounds have been performed with the density functional theory method. The study of calculations and optical diffuse reflectance experimental results show both compounds are insulators with direct band-gap.     

X射线法测量锗单晶的应力

采用Hiroshi Suzuki等人提出的新的单晶应力测量原理,结合不对称布拉格衍射技术,对锗单晶的应力进行了测量。这种方法的优点在于利用多组试验数据求解多元线性回归方程,从而消除了一般单晶应变测定方法中无应变状态下晶面间距不准确对结果所带来的影响。该法可以推广应用于其他单晶体的应力测量和高织构取向材料的X射线应力测量。     

热退火对KDP晶体微结构的影响

用X射线衍射和Raman光谱技术研究了KDP晶体165℃退火前后微观结构的变化。实验发现退火24h可以减小晶体生长过程中带来的晶格的畸变，提高了晶体的完整性，缩小晶体中键长和键角的变化范围，使晶体内应力得以部分释放。对于快速生长的晶体，退火的效果更加显著。     

单晶材料X射线应力测定原理与方法

结合单晶X射线应力测定基本原理,通过必要的理论分析,对现有单晶应力测定方法进行必要的改进和优化。基于工程实际应用需要,精简了单晶应力测定步骤并拓宽其应用范围,即不需要事先精确已知200,只需改变空间方位角驴和驴,再通过多元线形回归分析方法即可计算出各应力分量。最后给出了单晶应力测定的典型实例,即对同一部位重复测定应力,证实测量误差不超过±20MPa,说明该方法具有较高的测量精度和可靠性。     

一个与准晶相关的新Al—Cu相

本文报道一个新Ａｌ－Ｃｕ相,具有正交结构,空间群Ｆｄｄｄ,点阵常数为：ａ＝０．８１６６ｎｍ,ｂ＝０．９９９５ｎｍ,ｃ＝１．４１４９ｎｍ,表达式为Ａｌ４３．２Ｃｕ５６．８,该相与Ａｌ－Ｃｕ－Ｆｅ准晶的价电子浓度相同,是一个由ＣｓＣｌ结构衍生的类似相。