ACTIVE-ILMENITE SURFACE STRUCTURE INFLUENCE ON ACID-ASSISTED BALL MILLING

2018 ◽  
Vol 25 (Supp01) ◽  
pp. 1840006
Author(s):  
WEERACHON PHOOHINKONG ◽  
SORAPONG PAVASUPREE ◽  
KANOKTHIP BOONYARATTANAKALIN ◽  
WANICHAYA MEKPRASART ◽  
WISANU PECHARAPA
Keyword(s):  
Electron Microscope ◽  
Ball Milling ◽  
Sample Surface ◽  
Chemical Oxidation ◽  
Milling Process ◽  
Octahedral Cluster ◽  
Edge Structure ◽  
X Ray ◽  
Ball Milling Process ◽  
X Ray Absorption

Active-ilmenite powder derived from natural ilmenite sand was prepared by the ball milling process with acid-solution and Deionized (DI) water. Morphology and particle size of active-ilmenite product in acid/DI-assisted ball milling process were monitored by field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). Surface atomic component and chemical bonding were investigated by X-ray photoelectron spectroscopy (XPS). Meanwhile, bulk chemical oxidation and fine structure of active-ilmenite were studied by X-ray absorption near edge structure (XANES) and extended X-ray absorption ne-structure spectroscopy (EXAFS) to confirm the oxidation state and local active species structure at surface. Active-ilmenite by acid-assisted ball milling process is a distinctive method for the preparation of active-ilmenite product with high active surface. Moreover, the distortion of TiO6 and FeO6 octahedral cluster on the sample surface was detected in all milled samples with acid-assisted ball milling process. The presence of Fe[Formula: see text], Fe[Formula: see text] ions and miniature sulfate was also detected on the sample surface by milled product with acid-assisted method.

scholarly journals Characterization and x-ray absorption spectroscopy of ilmenite nanoparticles derived from natural ilmenite ore via acid-assisted mechanical ball-milling process

2017 ◽  
Vol 8 (3) ◽  
pp. 035012 ◽  
Author(s):  
Weerachon Phoohinkong ◽  
Sorapong Pavasupree ◽  
Anucha Wannagon ◽  
Samunya Sanguanpak ◽  
Kanokthip Boonyarattanakalin ◽  
...  
Keyword(s):  
Ball Milling ◽  
Absorption Spectroscopy ◽  
Milling Process ◽  
X Ray ◽  
Ball Milling Process ◽  
X Ray Absorption ◽  
Mechanical Ball Milling

scholarly journals Effect of Organic Assistant on the Performance of Ceria-Based Catalysts for the Selective Catalytic Reduction of NO with Ammonia

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 357 ◽  
Author(s):  
Huang ◽  
Li ◽  
Qiu ◽  
Chen ◽  
Cheng ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Ball Milling ◽  
Catalytic Reduction ◽  
Temperature Programmed Desorption ◽  
Milling Process ◽  
X Ray ◽  
Ball Milling Process ◽  
Nh3 Scr ◽  
Temperature Programmed ◽  
Catalytic Performances

In the present study, a series of CeO2/TiO2 catalysts were fabricated by dry ball milling method in the absence and presence of organic assistants, and their catalytic performances for the selective catalytic reduction (SCR) of NO by NH3 were investigated. It was found that the addition of organic assistants in the ball milling process and the calcining ambience exerted a significant influence on the catalytic performances of CeO2/TiO2 catalysts. The nitrogen sorption isotherm measurement (BET), powder X-ray diffraction (XRD), Raman spectra, high-resolution transmission electron microscopy (HR-TEM), hydrogen temperature-programmed reduction (H2-TPR), ammonia temperature-programmed desorption (NH3-TPD), sulfur dioxide temperature-programmed desorption (SO2-TPD), thermogravimetric analysis (TG), Fourier transform infrared (FT-IR) and X-ray photoelectron spectra (XPS) characterizations showed that the introduction of citric acid in the ball milling process could significantly change the decomposition process of the precursor mixture, which can lead to improved dispersion and reducibility of cerium species, surface acidity as well as the surface microstructure, all which were responsible for the high low temperature activity of CeTi-C-N in an NH3-SCR reaction. In contrast, the addition of sucrose in the milling process showed an inhibitory effect on the catalytic performance of CeO2/TiO2 catalyst in an NH3-SCR reaction, possibly due to the decrease of the crystallinity of the TiO2 support and the carbon residue covering the active sites.

X-RAY PHOTOEMISSION ELECTRON MICROSCOPE DETERMINATION OF ORIGINS OF ROOM TEMPERATURE FERROMAGNETISM AND PHOTOLUMINESCENCE IN HIGH Co-CONTENT CoxZn1-xO FILMS

2014 ◽  
Vol 21 (04) ◽  
pp. 1450058 ◽  
Author(s):  
WEI CAO ◽  
VLADIMIR PANKRATOV ◽  
MARKO HUTTULA ◽  
LIANA SHIRMANE ◽  
YU RAN NIU ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Luminescence Properties ◽  
Edge Structure ◽  
X Ray ◽  
Zno Nanoclusters ◽  
X Ray Absorption ◽  
Photoemission Electron

In this paper, we reported on the X-ray photoemission electron microscope (XPEEM) determination of magnetic and luminescence origins for two Co x Zn 1-x O films. The cobalt fraction x of radio frequency co-sputtered samples were 0.86(2) and 0.92(2), respectively. Films were ferromagnetic and semiconductive. Unique narrow green color lines beside the ZnO intrinsic emissions were found with a decay time in microsecond range at room temperature. Origins of magnetic and luminescence properties were determined with XPEEM. The X-ray absorption near edge structure at the Co  L3-edge denoted that Co was partially oxidized, and phase-contrast images together with chemical composition identification further proved that Co and CoO co-existed in the samples. The ferromagnetism was attributed to ferromagnetism of Co clusters partially canceled by the antiferromagnetism of its oxide, and the photoluminescence to bound exciton in ZnO nanoclusters and defect related centers of ZnO nanoclusters in a Co -rich matrix. Present results show possibilities for adjusting magnetic and luminescence properties of Co – ZnO compounds by changing the cobalt concentration.

Synchrotron X-ray Absorption Studies of Atomic-Level Alloying in Immiscible Mixtures

1998 ◽  
Vol 524 ◽  
Author(s):  
J.-H. He ◽  
P. J. Schilling ◽  
E. Ma
Keyword(s):  
Ball Milling ◽  
Room Temperature ◽  
High Energy ◽  
Atomic Level ◽  
High Energy Ball Milling ◽  
Edge Structure ◽  
X Ray ◽  
Energy Ball ◽  
Immiscible Mixtures ◽  
X Ray Absorption

ABSTRACTAn X-ray absorption beamline has been developed recently at the electron storage ring of the LSU Center for Advanced Microstructures and Devices. Using Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Structure (XANES), we have studied the local atomic environments in immiscible mixtures processed by high-energy ball milling, a mechanical alloying technique involving heavy deformation. By examining the local coordination and bond distances, it is concluded that atomic-level alloying can indeed be induced between Cu and Fe through milling at room temperature, forming substitutional fcc and bcc solid solutions. In addition to single-phase regions, a two-phase region consisting of fcc/bcc solutions has been found after milling at both room temperature and liquid nitrogen temperature. In contrast to the Cu-Fe system, solid solution formation is not detectable in milled Ag-Fe and Cu-Ta mixtures. This work demonstrates the power of synchrotron EXAFS/XANES experiments in monitoring nonequilibrium alloying on the atomic level. At the same time, the results provide direct experimental evidence of the capability as well as limitations of high-energy ball milling to form alloys in positive-heat-of-mixing systems.

Study of X-ray absorption near-edge structure with a photoemission electron microscope

2006 ◽  
Vol 38 (4) ◽  
pp. 574-578
Author(s):  
Zengming Zhang ◽  
Zejun Ding ◽  
Hideki Yoshikawa ◽  
Ryuichi Shimizu
Keyword(s):  
Electron Microscope ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption ◽  
Photoemission Electron

Stoichiometric Study of Iron Sulfide Prepared by Mechanochemical Reaction

2007 ◽  
Vol 561-565 ◽  
pp. 2099-2102 ◽  
Author(s):  
Chung Kwei Lin ◽  
Chin Yi Chen ◽  
Pee Yew Lee ◽  
Chih Chieh Chan
Keyword(s):  
Ball Milling ◽  
Nearest Neighbor ◽  
Iron Sulfide ◽  
Structural Evolution ◽  
High Energy ◽  
Mechanochemical Reaction ◽  
Iron Sulfides ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

In the present study, pure elemental powders of Fe and S were mixed to give the desired compositions of Fe50S50. A SPEX 8000D high-energy ball mill was used to synthesize iron sulfide powders under an Ar-filled atmosphere. The prepared powders were examined by conventional X-ray diffractometry and synchrotron X-ray absorption spectroscopy. The experimental results revealed that mechanochemical reactions occurred during the ball milling process for all the compositions. The Fe50S50 phase was obtained after ball milling for 20 h. Extended X-ray absorption fine structure (EXAFS) results revealed that the nearest neighbor bond lengths of the radial distribution function (RDF) for iron decreased when iron sulfides formed. X-ray absorption near edge structure (XANES) of S K-edges distinguished better the structural evolution of these iron sulfides.

Soft X-Ray Absorption Microscopy of Surfaces with Synchrotron Radiation

1988 ◽  
Vol 143 ◽  
Author(s):  
G. R. Harp ◽  
B. P. Tonner
Keyword(s):  
Synchrotron Radiation ◽  
Sample Surface ◽  
Spectroscopic Technique ◽  
Solid Surfaces ◽  
Chemical Information ◽  
Secondary Electrons ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

AbstractAs a spectroscopic technique, x-ray absorption near-edge structure (XANES) of core-levels using synchrotron radiation is in wide-spread use for the determination of the molecular composition of solid surfaces. A common detection method measures the yield of secondary electrons, which is proportional to the x-ray absorption coefficient for sufficiently high photon energy. In the experiments reported here, we show how the secondary electrons emitted as a result of photoabsorption can be used to generate a magnified image of the sample surface, with fundamental spatial limits determined by the deBroglie wavelength of the emitted electrons. Contrast in the secondary electron spatial distribution contains both topographical and chemical information about the sample surface. The use of tunable synchrotron radiation enables us to separate these contributions to the microscopic image, and to spatially resolve surface chemical composition as reflected in micro-XANES spectra.

Quasi Crystal Al (1xxx)/Carbonised Coconut Shell Nanoparticles: Synthesis and Characterisation

MRS Advances ◽  
2018 ◽  
Vol 3 (42-43) ◽  
pp. 2559-2571 ◽  
Author(s):  
Sefiu A. Bello ◽  
Johnson O. Agunsoye ◽  
Jeleel A. Adebisi ◽  
Funsho O. Kolawole ◽  
Nasirudeen K. Raji ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Ball Milling ◽  
Milling Process ◽  
Coconut Shell ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Ball Milling Technique ◽  
The Individual ◽  
Average Size

AbstractA novel synthesis of Al (1xxx)/carbonised coconut shell (CCS) nanoparticles using a ball milling technique was investigated. Initial Al/0.1%CCS powders of an average size of 51.06μm was milled for a period of 70 h. The milled particles at 16, 46 and 70 h were characterized using X-ray diffractomer (XRD), scanning electron microscope (SEM), transmission electron microscope and UV-Vis spectrophotometer. Result revealed that the calculated particle crystallite size from XRD aided with Scherrer’s equation is consistent with particle image sizes obtained from SEM aided with software. TEM image depicted variation in orientation and appearance of the Al 1xxx/0.1% CCS nanoparticles at different milling time. The wide variation in the particle size is attributable to different ball impacts on the individual powders during the ball milling process. Increased maximum absorbance observed with the milled particles when compared with the initial powders is an indication of quantum/nanosizing effect due to ball milling.

Calculations of oxygen electron energy loss near edge structure

1987 ◽  
Vol 45 ◽  
pp. 128-129
Author(s):  
Xudong Weng ◽  
Peter Rez
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Energy Loss ◽  
Electron Energy ◽  
Nearest Neighbour ◽  
Edge Structure ◽  
X Ray ◽  
Electron Energy Loss ◽  
X Ray Absorption ◽  
Widespread Interest

Most analytical microscopes are equipped with energy loss spectrometers capable of giving spectra showing 1-2 eV resolution for inner shell edges. The relatively weak modulation starting 30-50 eV from threshold due to Extended X-ray Edge Energy Loss Fine Structure (EXELFS) which is analogous to EXAFS in X-ray absorption has been studied in some detail. Although the theory is, in principle, straightforward the technique using energy loss in the electron microscope to determine nearest neighbour distances has not attracted widespread interest. This is partly due to the long counting times involved. The near edge structure (NES) within 20-30 eV of threshold is characterized by a very strong modulation and is clearly visible even when small amounts of the element are present. Interpretation of the features is very much more difficult and except in those cases in which peaks can be clearly assigned to transitions to antibonding orbitals the main form of analysis has been limited to simple comparisons or fingerprinting.

scholarly journals Mechanical properties of the Al-Mg/MWCNTs composite powders: The effects of ball milling process parameters

2021 ◽  
Author(s):  
Hossein Ahmadian
Keyword(s):  
Mechanical Properties ◽  
Ball Milling ◽  
Milling Time ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
X Ray ◽  
Ball Milling Process ◽  
Carbon Nano Tubes ◽  
Ball Milling Time

Abstract The effects of multi-walled carbon nano-tubes (MWCNTs) and the ball milling parameters on the mechanical properties of the Al-Mg alloy powders were investigated. Three different composite powders were synthesized through ball-milling process at different time and milling rates. The microstructural and phase analyses were carried out via scanning electron microscopy and X-ray diffraction spectroscopy, respectively. The results indicated that increasing the ball-milling time and rate would lead to the formation of finer particles, which consequently intensifies the plastic deformation and then, results in lower crystallite size. The morphological investigations indicated that while the MWCNTs agglomerates in lower milling rates, increased milling rate not only improve the distribution of the MWCNTs, but also decreases the length of the nano-tubes and promotes their diffusion into Al-Mg matrix. The formation of Al-Mg intermetallic phases through the ball-milling process of the composite powders was also confirmed via microstructural investigations.

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