Metastable Phases of Alumina

1983 ◽  
Vol 21 ◽  
Author(s):  
A. Dauger ◽  
D. Fargeot ◽  
J.P. Laval
Keyword(s):  
Electron Microscopy ◽  
Spinel Structure ◽  
X Ray Diffraction ◽  
Cationic Sublattice ◽  
Antiphase Boundaries ◽  
Pure Alumina ◽  
X Ray ◽  
Transmission Electron ◽  
Plasma Sprayed ◽  
Metastable Forms

ABSTRACTPlasma sprayed pure alumina samples have been studied by Transmission Electron Microscopy and X–Ray diffraction. The main families of metastable forms (γ δ and θ) have been observed in as-sprayed or in annealed states. All derive from a spinel structure through a periodic antiphase boundaries mechanism, together with an ordering of vacant sites in the cationic sublattice.

The Preparation and Properties of Seawater Purification and Resource Recycling Function Materials

2011 ◽  
Vol 233-235 ◽  
pp. 677-679
Author(s):  
Qi Huang ◽  
Wei Ma ◽  
Mei Han
Keyword(s):  
Electron Microscopy ◽  
Manganese Oxide ◽  
Spinel Structure ◽  
Lithium Manganese Oxide ◽  
Phenol Removal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resource Recycling ◽  
Lithium Manganese ◽  
Transmission Electron

A kind of manganese oxide which could purify seawater arisesed at the historic moment. Lithium manganese oxide was synthesized by coprecipitation method and the manganese oxide was prepared by extracting lithium from lithium manganese oxide. The characteristics of the manganese oxide were studied by X-ray diffraction and transmission electron microscopy. The characteristics showed that the manganese oxide was pure spinel structure and about 100 nm in length. There were experiments to study the effects of oil and phenol removal in the seawater. At the same time recycling lithium from seawater was tested. The results showed that the manganese oxide could not only remove oil and phenol but also recycle lithium.

Microstructural Investigation of RE3(Fe.V) 29 (RE = Nd, Tb) Magnetic Materials

1999 ◽  
Vol 577 ◽  
Author(s):  
J. Bernardi ◽  
M. Noner ◽  
J. Fidler ◽  
X.F. Han ◽  
F.M. Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Type Structure ◽  
X Ray Diffraction ◽  
Antiphase Boundaries ◽  
Microstructural Investigation ◽  
Space Group ◽  
X Ray ◽  
Arc Melting ◽  
Transmission Electron

ABSTRACTThe microstructure of V stabilized RE3(Fe,V)29 (RE=Nd,Tb) has been investigated by transmission electron microscopy (TEM). The investigated samples were prepared by arc melting and subsequent annealing above 910°C. X-ray diffraction confirms that the samples can be indexed based on a monoclinic Nd3(Fe,Ti)29-type structure (3:29) with A2/m space group. Our TEM investigation confirms that Nd3(Fe,V)29 contains usually grains with 3:29 structure and A 2/m space group. In addition grains with rhombohedral Th2Zn17 structure are observed regularly. The Tb3(FeV)29 alloy consists also of grains with monoclinic Nd3(Fe,Ti)29-type structure and contains a high density of planer defects like crystallographic twins or antiphase boundaries. Twinning occurs preferably on (402) of the monoclinic 3:29 structure. No tetragonal RE(Fe,V)12 phase or Fe is found.

Microstructure Study of Spinel Plasma Coatings

1998 ◽  
Author(s):  
G. Lallemand ◽  
S. Fayeulle ◽  
D. Treheux ◽  
C. Esnouf
Keyword(s):  
Electron Microscopy ◽  
X Ray Diffraction ◽  
Frequency Method ◽  
X Ray ◽  
Young’S Moduli ◽  
Transmission Electron ◽  
Splat Solidification ◽  
Coating Microstructure ◽  
Plasma Sprayed ◽  
Rate Gradient

Abstract Spinel powders of different compositions were fabricated fir their good properties of chemical resistance. These powders were plasma sprayed on steels and their microstructure was investigated by scanning electron microscopy (SEM), microanalysis, X-ray diffraction and transmission electron microscopy (TEM). Due to the powder fabrication process, coatings were very heterogeneous in composition, but had the spinel structure. TEM observations pointed out that splat solidification occured with a cooling rate gradient leading to different crystallization inside a lamella. Young's moduli by the coatings were measured by the resonant frequency method and the correlation with coating microstructure was discussed.

Antiphase Domains in Long-Period Superlattices

1968 ◽  
Vol 12 ◽  
pp. 129-138
Author(s):  
P. Chaudhari ◽  
A. Gangulee
Keyword(s):  
Electron Microscopy ◽  
Antiphase Boundary ◽  
Translation Vector ◽  
X Ray Diffraction ◽  
Antiphase Boundaries ◽  
One Dimensional ◽  
X Ray ◽  
Long Period ◽  
Transmission Electron ◽  
Antiphase Domains

AbstractThe antiphase boundary in a superlattice has been defined as the boundary between two neighboring zones which are out ofsphase with each other. This difference in phase is usually represented by a translation vector. In long-period superlattices, however, antiphase boundaries of the above mentioned type occur with regular spacings, thereby introducing another element of order which shows up as satellite peaks in the diffraction pattern. A second kind of antiphase boundaries may be defined in a one-dimensional long-period superlattice as the boundary between two neighboring zones which have different directions of repetition of the antiphase boundaries of the first kind. A theory of X-ray diffraction to obtain the size of the domains of the second kind in a one-dimensional long-period superlattice has been developed. An application of this theory to the ordered alloy Ag3Mg, known to have a one-dimensional long-period superlattice, is described and the results of the X-ray measurements are compared with those obtained by transmission electron microscopy.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

The Effect of the Microstructure of Diffusion Barriers on the Palladium Activation for Electroless Copper Deposition

2002 ◽  
Vol 716 ◽  
Author(s):  
Seok Woo Hong ◽  
Yong Sun Lee ◽  
Ki-Chul Park ◽  
Jong-Wan Park
Keyword(s):  
Electron Microscopy ◽  
Diffusion Barriers ◽  
Copper Deposition ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Electroless Copper ◽  
Sheet Resistance Measurement ◽  
Scanning Electron

AbstractThe effect of microstructure of dc magnetron sputtered TiN and TaN diffusion barriers on the palladium activation for autocatalytic electroless copper deposition has been investigated by using X-ray diffraction, sheet resistance measurement, field emission scanning electron microscopy (FE-SEM) and plan view transmission electron microscopy (TEM). The density of palladium nuclei on TaN diffusion barrier increases as the grain size of TaN films decreases, which was caused by increasing nitrogen content in TaN films. Plan view TEM results of TiN and TaN diffusiton barriers showed that palladium nuclei formed mainly on the grain boundaries of the diffusion barriers.

Palladium Nanowire Thin Films via Template Growth

2003 ◽  
Vol 775 ◽  
Author(s):  
Donghai Wang ◽  
David T. Johnson ◽  
Byron F. McCaughey ◽  
J. Eric Hampsey ◽  
Jibao He ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Conductive Substrate ◽  
Palladium Nanowires ◽  
Efficient Route ◽  
Silica Thin Film

AbstractPalladium nanowires have been electrodeposited into mesoporous silica thin film templates. Palladium continually grows and fills silica mesopores starting from a bottom conductive substrate, providing a ready and efficient route to fabricate a macroscopic palladium nanowire thin films for potentially use in fuel cells, electrodes, sensors, and other applications. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicate it is possible to create different nanowire morphology such as bundles and swirling mesostructure based on the template pore structure.

scholarly journals Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Archaeological Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared And Raman Spectroscopy ◽  
First Time ◽  
Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

Effect of synthesis and activation methods on the character of CoMo/ultrastable Y-zeolite catalysts

2021 ◽  
Vol 19 (1) ◽  
pp. 745-754
Author(s):  
Khoirina Dwi Nugrahaningtyas ◽  
Eddy Heraldy ◽  
Rachmadani ◽  
Yuniawan Hidayat ◽  
Indriana Kartini
Keyword(s):  
Electron Microscopy ◽  
Reduction Process ◽  
Particle Morphology ◽  
Zeolite Catalysts ◽  
X Ray Diffraction ◽  
Y Zeolite ◽  
X Ray ◽  
Irregular Particle ◽  
Transmission Electron ◽  
Pure Metals

Abstract The properties of three types of CoMo/USY catalysts with different synthesized methods have been studied. The sequential and co-impregnation methods followed by activation using calcination and reduction process have been conducted. The properties of the catalysts were examined using Fourier-transform-infrared (FTIR) spectroscopy, X-ray diffraction (XRD) with refinement, and surface area analyzer (SAA). The FTIR spectrum study revealed the enhanced intensity of its Bronsted acid site, and the XRD diffractogram pattern verified the composition of pure metals, oxides, and alloys in the catalyst. The SAA demonstrated the mesoporous features of the catalyst. Scanning electron microscopy showed an irregular particle morphology. Additional analysis using the transmission electron microscopy indicated that the metal has successfully impregnated without damaging the USY structure.

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