scholarly journals An X-ray microtomography study of particle morphology and the packing behaviour of metal powders during filling, compaction and ball indentation processes

2021 ◽  
Vol 385 ◽  
pp. 250-263
Author(s):  
Mozhdeh Mehrabi ◽  
Ali Hassanpour ◽  
Andrew Bayly
Keyword(s):  
Particle Morphology ◽  
Metal Powders ◽  
X Ray ◽  
Ball Indentation

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.

scholarly journals Surface Texture of Microcrystalline Tunnel-Structured Manganese(IV) Oxides: Nitrogen Sorptiometry and Electron Microscopy Studies

2002 ◽  
Vol 20 (7) ◽  
pp. 619-632 ◽  
Author(s):  
A.A. Ali ◽  
F.A. Al-Sagheer ◽  
M.I. Zaki
Keyword(s):  
Electron Microscopy ◽  
Chemical Composition ◽  
Surface Texture ◽  
Particle Morphology ◽  
High Resolution Electron Microscopy ◽  
Surface Chemical ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Surface Chemical Composition ◽  
Resolution Electron

Three different modifications of manganese(IV) oxide, viz. cryptomelane, nsutite and todorokite-like, were synthesized by hydrothermal methods. The bulk chemical composition, phase composition, crystalline structure and particle morphology of the resulting materials were determined by thermogravimetry, atomic absorption spectroscopy, X-ray diffractometry, infrared spectroscopy and scanning electron microscopy. The surface chemical composition, texture and structure were assessed using X-ray photoelectron microscopy, nitrogen sorptiometry and high-resolution electron microscopy. The results highlighted the hydrothermal conditions under which such tunnel-structured modifications of manganese(IV) oxide can be successfully synthesized. Moreover, they revealed that (i) the bulk was microcrystalline, (ii) the crystallites were either fibrils (cryptomelane and nsutite) or rod-like (todorokite) with low-index exposed facets, (iii) the surface chemical composition mostly reflected that of the bulk and (iv) the surface texture was linked with high specific areas, slit-shaped mesopores associated with particle interstices and micropores which allowed surface accessibility to the bulk tunnels of the test oxides. The application of such test oxides as shape-selective oxidation catalysts appears worthy of investigation.

INFLUENCE OF METAL POWDER PRODUCTION METHOD ON MICROSTRUCTURE AND FLUIDITY OF MAGNETICALLY ALLOY GRANULATE

2021 ◽  
Vol 2021 (9) ◽  
pp. 3-7
Author(s):  
Dmitriy Kostin ◽  
Aleksandr Amosov ◽  
Anatoliy Samboruk ◽  
Bogdan Chernyshev ◽  
Anton Kamynin
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Comparative Studies ◽  
Particle Morphology ◽  
Production Method ◽  
Magnetic Alloy ◽  
Gas Atomization ◽  
Metal Powders ◽  
Hard Magnetic Alloy

A comparison is made of the characteristics of metal powders of a hard magnetic alloy produced by centrifugal spraying and gas atomization. Comparative studies of particle morphology and particle size distribution of powders are presented in order to determine them.

Effect of High-Energy Ball Milling on Microstructure and Microwave Absorbing Properties of NdFe Material

2011 ◽  
Vol 311-313 ◽  
pp. 1281-1285 ◽  
Author(s):  
Pei Hao Lin ◽  
Lei Wang ◽  
Shun Kang Pan ◽  
Hua Mei Wan
Keyword(s):  
Ball Milling ◽  
Particle Morphology ◽  
High Energy ◽  
High Energy Ball Milling ◽  
X Ray ◽  
Microwave Absorbing Properties ◽  
Absorbing Materials ◽  
Milling Method ◽  
Energy Ball ◽  
Microwave Absorbing

The NdFe magnetic absorbing materials were prepared by rapid solidification and high-energy ball milling method. The effect of high-energy ball milling on particle morphology, organizational structure and microwave absorbing properties of NdFe magnetic absorbing materials were analyzed with the aid of X-ray diffractometer, scanning electron microscope and vector network analysis. The results show that the Nd2Fe17 and α-Fe phase are refined, the particles become smaller and thinner; the span-ratio of the particles increases along with time during the process of high-energy ball milling; and meanwhile, the frequency of absorbing peak reduces. The absorbing bandwidth broadens as the increase of the time of ball milling, except that of 48h.The minimum reflectance of the powder decreases from -22dB to - 44dB under the circumstances that the time of high energy ball milling reaches 48h and the thickness of the microwave absorbing coating is 1.5mm. But it rebounds to about - 6dB when the time of ball milling reaches 72h.

Well-defined colloidal tin(IV) oxide particles

1990 ◽  
Vol 5 (5) ◽  
pp. 1083-1091 ◽  
Author(s):  
Manuel Ocaña ◽  
Egon Matijević
Keyword(s):  
Dielectric Constant ◽  
Infrared Spectra ◽  
Particle Morphology ◽  
Spherical Particles ◽  
Degree Of Crystallinity ◽  
Narrow Size Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Additional Information ◽  
Oxide Particles

Spherical and rod-like SnO2 particles of narrow size distribution have been obtained by aging at 100°C acidified tin(IV) chloride solutions in the presence of urea or formamide. It was shown that spherical particles, the x-ray diffraction of which was characteristic of cassiterite, consisted of a large number of much smaller subunits. The rod-like particles had the same structure, but of higher degree of crystallinity. Infrared spectra of these powders were evaluated in terms of the theory of the average dielectric constant (TADC), in order to gain additional information on the particle morphology and the state of aggregation.

Effects of the Precursor Solution Addition Time in the Solochemical Synthesis of ZnO Nanocrystals

2012 ◽  
Vol 727-728 ◽  
pp. 856-860
Author(s):  
Marivone Gusatti ◽  
Carlos Eduardo Maduro de Campos ◽  
Gilvan Sérgio Barroso ◽  
Daniel Aragão Ribeiro de Souza ◽  
Camila Cardoso Milioli ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Precursor Solution ◽  
Particle Morphology ◽  
Wurtzite Phase ◽  
X Ray ◽  
Zno Nanocrystals ◽  
Transmission Electron ◽  
Nanometric Particles ◽  
Crystalline Domains ◽  
Hexagonal Wurtzite Phase

The solochemical method was applied to prepare ZnO nanocrystals at low temperature, using sodium hydroxide and zinc chloride as starting materials. In this work, different addition times of the precursor solution were adopted and their effects on the crystalline domains (or crystallite) size and particle morphology of the obtained samples were investigated. The synthesized products were characterized by X-ray powder diffraction (XRPD) and transmission electron microscopy (TEM) techniques. The XRPD results revealed that all samples produced have a single ZnO hexagonal wurtzite phase (space groupP63mc) under anisotropic strain. The parallel to perpendicular crystallite size ratio was about 1.21 for the sample produced with instantaneous addition of the precursor solution and 1.19 for 1 h longer addition time. The anisotropic strains become about 12% smaller for the sample produced with longer addition time. The TEM results of the samples showed ZnO nanometric particles with nearly rounded and rod-like morphologies.

X-ray photoelectron spectroscopic analysis of halloysites with different composition and particle morphology

Clay Minerals ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 413-421 ◽  
Author(s):  
M. Soma ◽  
G. J. Churchman ◽  
B. K. G. Theng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Cation Exchange Capacity ◽  
Spectroscopic Analysis ◽  
Surface Composition ◽  
Particle Morphology ◽  
Exchange Capacity ◽  
Surface Layers ◽  
X Ray ◽  
Fe Content ◽  
Before And After

AbstractThe surface composition of some halloysites with different particle morphology has been investigated by X-ray photoelectron spectroscopy (XPS) before and after removal of external Fe. The Fe(III) 2p3/2 binding energy of external Fe is appreciably smaller than that of structural Fe. Particle morphology is influenced by structural Fe content. The long-tubular halloysite has very little surface Fe, and its concentration tends to increase with the proportion of non-tubular particles in the samples. The spheroidal sample contains the most structural Fe which, however, does not appear to influence particle shape directly. Study by XPS indicates that Fe substitutes for Al in octahedral positions in approximately 1 : 2 proportion. As a result, an increase in octahedral vacancies and cation exchange capacity would be predicted. Further, halloysite layers within a crystal are generally inhomogeneous in composition. Built up like “onion skins”, the surface layers would either be enriched or depleted in Fe depending on the chemical environment in which crystal growth occurs.

scholarly journals Formation and Application of High Reflectivity Controllable Barium Sulfate Microspheres

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 333 ◽  
Author(s):  
Yuejiao Liu ◽  
Xiaoyan Guo ◽  
Qingyang Gu ◽  
Guangxiang He ◽  
Suohe Yang ◽  
...  
Keyword(s):  
Barium Sulfate ◽  
Ethylenediaminetetraacetic Acid ◽  
Density Lipoprotein ◽  
High Sensitivity ◽  
Particle Morphology ◽  
Disodium Edta ◽  
Reaction Conditions ◽  
X Ray ◽  
High Reflectivity ◽  
Good Repeatability

This paper investigated the influence of reaction conditions on particle morphology. X-ray powder diffraction (XRD), particle size distribution (PSD), and scanning electron microscopy (SEM) were used to characterize the morphology of barium sulfate. The barium sulfate microspheres were synthesized with BaCl2, Na2SO4, and ethylenediaminetetraacetic acid disodium (EDTA·2Na). The reflectivity of the synthesized barium sulfate microspheres was greater than 99% in the range of 400–700 nm, which was characterized by a reflectance spectrometer. The morphology of the barium sulfate particles and their cross-section were observed by SEM. The prepared microspheres were applied to high-density lipoprotein dry tablets due to their high reflectivity, and the results showed that the prepared tablets had high sensitivity and good repeatability.

X-Ray Fluorescence Analysis of Tungsten-Molybdenum Metals and Electrolytes

1960 ◽  
Vol 4 ◽  
pp. 474-487
Author(s):  
K. R. Stever ◽  
J. L. Johnson ◽  
H. H. Heady
Keyword(s):  
Internal Standard ◽  
Fluorescence Analysis ◽  
Metal Powders ◽  
Soft Or ◽  
X Ray ◽  
Molybdenum Metal ◽  
Fused Salts ◽  
Hard Radiation ◽  
Impurity Elements

AbstractAn X-ray fluorescence method is presented for the analysis of tungsten-molybdenum solutions. Tungsten and molybdenum metal powders, produced by a fused-salt electrolysis procedure, are dissolved and analyzed for tungsten and molybdenum by using the W La1, Pt La1 intensity ratios. The platinum spectral line from the X-ray tube target serves as a self-internal standard. The sensitivity limit is about 0,05% and in the concentration range of 0.5 to 100%, the accuracy of analysis is within about 2% standard deviation. The technique is also applied to the analysis of tungsten and molybdenum in fused salts and to the determination of several other Impurity elements in these metals.A double detector modification for the General Electric X-ray unit is described. The detector consists of a double-window flow proportional counter tube backed up by a sealed krypton-filled counter tube. This allows counting of either soft or hard radiation at maximum efficiencies without the necessity of changing counter tubes. Advantages in specific applications are discussed.

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