Phase Formation in a Wedged Au-Ag-Cu Multilayered Structure

1993 ◽  
Vol 311 ◽  
Author(s):  
I. Goldfarb ◽  
E. Zolotoyabko ◽  
D. Shechtman

ABSTRACTAn advanced method for investigation of multicomponent systems is proposed. Thin wedged-shape films of pure components are subsequently deposited to form a multilayered structure with continuously-varying composition as a function of sample location, providing a large number of differently composed samples in one deposition run. Each sample is then subjected to various heat treatments, and phase content as well as the microstructure formed is under investigation.In this study an Au-Ag-Cu multilayered structure was sputtered at a room temperature onto 55 Formvar-coated Mo grids. The satellite-like X-Ray Diffraction (XRD) patterns of these samples revealed the formation of an artificial composition-modulated ternary superlattice, complete destruction of which was observed during heat treatments, where phase formation according to the ternary Au-Ag-Cu phase diagram took place.Several aspects of phase formation were analyzed using XRD, Electron Probe for Micro- Analysis (EPMA) in Scanning Electron Microscopy (SEM), and Scanning Transmission Electron Microscopy (STEM) combined with Selected Area Electron Diffraction (SAED), Digital X-Ray Mapping (DXM), Secondary Electron Mapping and EPMA methods.

2010 ◽  
Vol 97-101 ◽  
pp. 4213-4216
Author(s):  
Jian Xiong Liu ◽  
Zheng Yu Wu ◽  
Guo Wen Meng ◽  
Zhao Lin Zhan

Novel single-crystalline SnO2 zigzag nanoribbons have been successfully synthesized by chemical vapour deposition. Sn powder in a ceramic boat covered with Si plates was heated at 1100°C in a flowing argon atmosphere to get deposits on a Si wafers. The main part of deposits is SnO2 zigzag nanoribbons. They were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). SEM observations reveal that the SnO2 zigzag nanoribbons are almost uniform, with lengths near to several hundred micrometers and have a good periodically tuned microstructure as the same zigzag angle and growth directions. Possible growth mechanism of these zigzag nanoribbons was discussed. A room temperature PL spectrum of the zigzag nanoribbons shows three peaks at 373nm, 421nm and 477nm.The novel zigzag microstructures will provide a new candidate for potential application.


2010 ◽  
Vol 8 (5) ◽  
pp. 1027-1033 ◽  
Author(s):  
Junhao Zhang ◽  
Yuhui Wu ◽  
Jia Zhu ◽  
Shaoxing Huang ◽  
Dongjing Zhang ◽  
...  

AbstractSelf-assembled CdS architectures with flower-like structures have been synthesized by a mixed solvothermal method using ethylene glycol and oleic acid as the mixed solvent at 160°C for 12 h. The results of X-ray diffraction (XRD) patterns, field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images indicate that the product exists as the hexagonal wurtzite phase and conatins of larger numbers of flower-like CdS architectures with diameters of 1.8–3 μm. The selected-area electron diffraction (SAED) pattern and the high resolution transmission electron microscope (HRTEM) image reveal that the grain has better crystallinity. The optical properties of flower-like CdS architectures were also investigated by ultraviolet-visable (UV-vis) and photoluminescence spectroscopy at room temperature. A strong peak at 490 nm is shown in the UV-vis absorption, while an emission at 486 nm and another strong emission at 712 nm are shown in the PL spectrum.


Clay Minerals ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 391-404 ◽  
Author(s):  
J. E. F. C. Gardolinski ◽  
G. Lagaly ◽  
M. Czank

AbstractKaolinite and synthetic γ-Al(OH)3 (gibbsite or hydrargillite) were reacted with phenylphosphonic, phenylphosphinic and 2-nitrophenol-4-arsonic acids. The products were studied by powder X-ray diffraction, transmission electron microscopy/selected area electron diffraction/ energy dispersive X-ray/Fourier transform infrared and simultaneous thermogravimetric/differential thermal analysis. The acids were not intercalated but, instead, easily destroyed the structure of the minerals. Lamellar Al phenylphosphonate and aluminium phenylphosphinate and phenylarsonate with polymeric linear-chain structures were formed from kaolinite. The reaction between gibbsite and the same acids yielded almost identical products. No evidence of formation of grafted kaolinite derivatives after the reaction with phenylphosphonic acid was found.


Clay Minerals ◽  
2008 ◽  
Vol 43 (4) ◽  
pp. 597-613 ◽  
Author(s):  
M. A. Sequeira Braga ◽  
C. Leal Gomes ◽  
J. Duplay ◽  
H. Paquet

AbstractNamacotche gem-bearing pegmatites of Alto Ligonha pegmatite district are heterogeneous, strongly fractionated, and have large Li and Ta and extremely large Cs contents. Clay samples were collected in fracture infillings and dilation cavities with gemstones and were studied using X-ray diffraction (XRD), polarized light microscope, scanning electron microscopy-energy dispersive spectroscopy, high-resolution transmission electron microscopy and chemical analyses. The <2 μm fraction contains cookeite, illite, illite-smectite and suggested irregular mixed-layer cookeite-smectite, beidellite, montmorillonite, kaolinite and goethite.The XRD patterns of chlorite and their d values suggest the presence of ‘di-trioctahedral chlorite’ similar to cookeite-Ia polytype. Cookeite chemical analyses show that Li contents range from 0.82 to 1.08 atoms per half unit cell.A close relationship has been established between occurrences of gemstones and clay minerals. Some important textures and crystal chemistry are discussed.The main gemstones related to the Namacotche Pegmatite are: morganite (pink cesian beryl), kunzite (spodumene) and elbaite tourmaline. As the mechanisms responsible for the gemstone formation take place at low temperature, the clay minerals paragenesis cookeite ± cookeite-smectite interstratification ± beidellite + montmorillonite ± illite-smectite interstratification, represents a late-stage secondary paragenesis, generated by hydrothermal alteration.


2011 ◽  
Vol 233-235 ◽  
pp. 1954-1957
Author(s):  
Xiao Yan Yan ◽  
Zhi Qiang Wei ◽  
Li Gang Liu ◽  
Xiao Juan Wu ◽  
Ge Zhang

Helical structure ZnS were successfully prepared via solvothermal method by the reaction of zinc acetate and sodium sulphide. The composition, morphology, and microstructure of the sample were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), the corresponding selected area electron diffraction (SAED) and X-ray energy spectrum (EDS). The experiment results show that the sample is 1-D hexagonal crystal ZnS and grows along the [002] direction, and is helical structure, with lengths in the range of 100-200 nm, the diameter about 5-15 nm, and pitch about 20nm.


2001 ◽  
Vol 15 (30) ◽  
pp. 1455-1458 ◽  
Author(s):  
H. CHEN ◽  
X. K. LU ◽  
S. Q. ZHOU ◽  
X. H. HAO ◽  
Z. X. WANG

Single phase AlN nanowires are fabricated by a sublimation method. They were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), typical selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). The SEM and TEM images show that most of the nanowires have diameters of about 10–60 nm. The crystal structure of AlN nanowires revealed by XRD, SAED and HRTEM shows the AlN nanowires have a wurtzite structure.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
G. Sathiyadevi ◽  
B. Loganathan ◽  
B. Karthikeyan

The solvent-mediated eco-friendly monodispersed Ag/Pd bimetallic nanocomposites (BNCs) having thick core and thin shell have been prepared through novel green chemical solvent reduction method. Reducing solvent, dimethyl formamide (DMF) is employed for the controlled green synthesis. Characterization of the synthesized Ag/Pd BNCs has been done by x-ray diffraction (XRD) studies, high-resolution scanning electron microscopy (HR-SEM), energy-dispersive X-ray analysis (EDX), and high-resolution transmission electron microscopy (HR-TEM) with selected area electron diffraction (SAED) pattern. The nature of the interaction of L-cysteine with Ag/Pd BNCs has been studied by using surface plasmon spectroscopy, Fourier transform-infrared spectroscopy (FT-IR), cyclic voltammetry (CV), and theoretical methods.


2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Fei Long ◽  
Shuyi Mo ◽  
Yan Zeng ◽  
Shangsen Chi ◽  
Zhengguang Zou

Flower-like Cu2ZnSnS4(CZTS) nanoflakes were synthesized by a facile and fast one-pot solution reaction using copper(II) acetate monohydrate, zinc acetate dihydrate, tin(IV) chloride pentahydrate, and thiourea as starting materials. The as-synthesized samples were characterized by X-ray diffraction (XRD), Raman scattering analysis, field emission scanning electron microscopy (FESEM) equipped with an energy dispersion X-ray spectrometer (EDS), transmission electron microscopy (TEM), and UV-Vis absorption spectra. The XRD patterns shown that the as-synthesized particles were kesterite CZTS and Raman scattering analysis and EDS confirmed that kesterite CZTS was the only phase of product. The results of FESEM and TEM show that the as-synthesized particles were flower-like morphology with the average size of 1~2 μm which are composed of 50 nm thick nanoflakes. UV-Vis absorption spectrum revealed CZTS nanoflakes with a direct band gap of 1.52 eV.


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