scholarly journals Testing the Debye Function Approach on a Laboratory X-ray Powder Diffraction Equipment. A Critical Study.

2013 ◽  
Vol 28 (S2) ◽  
pp. S11-S21 ◽  
Author(s):  
Ruggero Frison ◽  
Antonio Cervellino ◽  
Giuseppe Cernuto ◽  
Antonietta Guagliardi ◽  
Norberto Masciocchi
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Function Analysis ◽  
Average Particle Size ◽  
Lattice Parameter ◽  
Critical Study ◽  
Average Particle ◽  
Debye Function ◽  
Laboratory Equipment ◽  
Nanosized Materials

Total Scattering Methods are nowadays widely used for the characterization of defective and nanosized materials. They commonly rely on highly accurate neutron and synchrotron diffraction data collected at dedicated beamlines. Here, we compare the results obtained on conventional laboratory equipment and synchrotron radiation when adopting the Debye Function Analysis method on a simple nanocrystalline material (a synthetic iron oxide with average particle size near to 10 nm). Such comparison, which includes the cubic lattice parameter, the sample stoichiometry and the microstructural (size-distribution) analyses, highlights the limitations, but also some strengthening points, of dealing with conventional powder diffraction data collections on nanocrystalline materials.

Influence of Excess Bi2O3 and Na2Co3 on Crystal Structure and Microstructure of Bismuth Sodium Titanate Ceramics

2011 ◽  
Vol 474-476 ◽  
pp. 1711-1714 ◽  
Author(s):  
Panadda Sittiketkron ◽  
Arrak Klinbumrung ◽  
Theerachai Bongkarn
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Perovskite Phase ◽  
Average Particle Size ◽  
Sodium Titanate ◽  
Solid State Reaction Method ◽  
Lattice Parameter ◽  
Rhombohedral Structure ◽  
Average Particle ◽  
Average Grain Size

This study investigated the influence of excess Bi2O3 and Na2CO3 on the crystal structure, microstructure and dielectric properties of (Bi0.5Na0.5)TiO3 (BNT) ceramics. The BNT ceramics were synthesized using the solid-state reaction method with various excess Bi2O3 and Na2CO3 levels (0, 1, 2, 3 and 4 mol%). The X-ray characterization revealed that all samples had a rhombohedral structure. A pure perovskite phase was obtained in all samples. The lattice parameter a tended to increase with increased excess Bi2O3 and Na2CO3 content in the calcined powders and sintered ceramics. The average particle size increased while, the average grain size tended to decreased with increased of excess Bi2O3 and Na2CO3 content. The depolarization temperature (Td) and the Curie temperature (Tc) were slightly decreased with the increase of excess Bi2O3 and Na2CO3 content. The dielectric properties were related to the density.

X-ray powder diffraction data of CoSi

1997 ◽  
Vol 12 (4) ◽  
pp. 252-254 ◽  
Author(s):  
G. Ghosh ◽  
G. V. Narasimha Rao ◽  
V. S. Sastry ◽  
A. Bharathi ◽  
Y. Hariharan ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Melting Process ◽  
Lattice Parameter ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
Arc Melting ◽  
Cubic Structure

X-ray powder diffraction data of CoSi are reported. The sample was prepared by an arc melting process and has a cubic structure (space group P213, space group No. 198) with lattice parameter a=4.4427 Å, Dx=6.591 gcm−3, Z=4, and I/Ic=1.03.

scholarly journals A review of Debye Function Analysis

2013 ◽  
Vol 28 (S2) ◽  
pp. S2-S10 ◽  
Author(s):  
Kenneth R. Beyerlein
Keyword(s):  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Function Analysis ◽  
Reciprocal Space ◽  
Spherical Particles ◽  
Complete Agreement ◽  
Line Profiles ◽  
Debye Function

The employment of the Debye function to model line profiles in the powder diffraction pattern from small crystallites is briefly reviewed. It is also demonstrated that for the case of very small spherical particles, it is necessary to average patterns from multiple constructions of the particle to have complete agreement with reciprocal space models. In doing so it is demonstrated that the technique of Debye function analysis is best suited for systems with only a few possible atomic arrangements.

Microstructural and Magnetic Properties of Nanostructured Fe65Co35 Powders Prepared by Mechanical Alloying

2013 ◽  
Vol 829 ◽  
pp. 778-783 ◽  
Author(s):  
Mohsen Razi ◽  
Ali Ghasemi ◽  
Gholam Hossein Borhani
Keyword(s):  
Magnetic Properties ◽  
Mechanical Alloying ◽  
Milling Time ◽  
Cooling System ◽  
Average Particle Size ◽  
Weight Ratio ◽  
Lattice Parameter ◽  
Milling Process ◽  
Protective Atmosphere ◽  
Average Particle

Nanostructured Fe65Co35 alloy powders were fabricated by mechanical alloying in an attritor mill with different milling times. The milling process carried out in speed of 350 rpm, with 20:1 ball to powder weight ratio and under argon protective atmosphere. A continuous cooling system applied to avoid increasing temperature during the milling. The effect of milling time on structural and magnetic properties investigated by X-ray diffraction, scanning electron microscopy and vibration sample magnetometer. According to the obtained results, nanostructured Fe65Co35 solid solution powders resulted with an average particle size of 400 nm and crystallite size of 6.8 nm by milling for 20 hours. With increasing the milling time, the lattice parameter decreased and the lattice strain increased for Fe65Co35 powders. The maximum saturation magnetization with 1311 emu/cc value and the minimum coercivity with 22 Oe value occurs after milling for 15 hours.

X-ray powder diffraction data for ErH2−xDx

2008 ◽  
Vol 23 (3) ◽  
pp. 259-264 ◽  
Author(s):  
Mark A. Rodriguez ◽  
Robert M. Ferrizz ◽  
Clark S. Snow ◽  
James F. Browning
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Room Temperature ◽  
Lattice Parameter ◽  
Powder Diffraction Data ◽  
Mole Percent ◽  
X Ray ◽  
Cubic Lattice ◽  
Fluorite Type ◽  
Hydrogen Deuterium

X-ray powder diffraction data for ErH2−xDx formed by hydrogen (i.e., protium)–deuterium loading of Er metal are reported. Lattice parameters for the varying hydrogen–deuterium compositions followed Vergard’s law behavior. The cubic lattice parameter at room temperature for ErH2−xDx obeys a linear relationship according to the formula a=5.1287−1.1120×10−4⋅x, where a is the lattice parameter of the fluorite-type structure and x is the mole percent of deuterium. Microstrain measurements suggest a possible ordering of hydrogen and deuterium in the composition ErH1D1.

X-ray powder diffraction data for rhombohedral AlPt

2006 ◽  
Vol 21 (4) ◽  
pp. 318-319
Author(s):  
Mark A. Rodriguez ◽  
David P. Adams
Keyword(s):  
Thin Film ◽  
High Temperature ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Lattice Parameter ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray ◽  
High Temperature Reactions

X-ray powder diffraction data for a rhombohedral AlPt phase formed by self-propagating, high-temperature reactions of Al∕Pt bi-layer films are reported. Multilayer Al∕Pt thin film samples, reacted in air or vacuum, transformed into rhombohedral AlPt with space group R-3(148). Indexing and lattice parameter refinement of AlPt powders (generated from thin-film samples) yielded trigonal/hexagonal unit-cell lattice parameters of a=15.623(6) Å and c=5.305(2) Å, Z=39, and V=1121.5 Å3.

Analysis of the Promoter-Catalyst interaction between Mn and Rh by Transmission Electron Microscopy

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
B. Graham ◽  
R.F. Klie
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Average Particle Size ◽  
Lattice Parameter ◽  
Average Particle ◽  
Fischer Tropsch ◽  
Transmission Electron ◽  
Three Samples ◽  
Promoter Interaction

In the hope of optimizing the Fischer-Tropsch mechanism to produce cleaner ethanol, the catalyst- promoter interaction between rhodium and manganese was examined by transmission electron microscopy. Three samples were analyzed on a carbon nanotube (CNT) substrate with 3 wt% rhodium (3%Rh/CNT), 1% manganese with 3 wt% rhodium (1%Mn/3% Rh/CNT), and 2% manganese with 3 wt% rhodium (2% Mn/3% Rh/CNT). The average particle size were found to be (1.9 ± 0.6) nm, (2.1 ± 0.5) nm, and (3.2 ± 0.6) nm, respectively. An increase in particle size indicates that the rhodium and manganese are interacting. The lattice parameter for rhodium were also determined to be (4.1 ± 0.1) Å, (4.2 ± 0.1) Å, and (3.8 ± 0.1) Å, respectively. The decrease in lattice parameter in the 2%Mn/3%Rh/CNT sample was most likely due to a change in the crystal structure of the rhodium particles as a result of the interaction between the manganese and rhodium.

Fabrication of Barium Stannate Tatanate Ceramics via Combustion Technique

2008 ◽  
Vol 55-57 ◽  
pp. 173-176 ◽  
Author(s):  
C. Wattanawikkam ◽  
Theerachai Bongkarn
Keyword(s):  
Perovskite Phase ◽  
Average Particle Size ◽  
Combustion Method ◽  
Lattice Parameter ◽  
Average Particle ◽  
Calcination Temperatures ◽  
Grain Sizes ◽  
Barium Stannate ◽  
Calcined Temperature ◽  
Combustion Technique

The effect of firing temperatures on phase formation and microstructure of barium stannate titanate [Ba(Sn0.1Ti0.9)O3; BST10] ceramics were investigated. BST10 was synthesized via a combustion method, at various calcination and sintering temperatures. It was found that, a single perovskite of BST10 powders was obtained with a calcinations temperature of 1200 oC. The percent of the perovskite phase and the lattice parameter were increased with increasing calcination temperatures. The average particle size was increased from 0.48 to 1.69 µm by increasing the calcined temperature from 600 to 1200 oC. The average grain sizes were increased from 0.99 to 17.77 µm by increasing the sintering temperature from 1250 to 1450 oC. The maximum density and dielectric constant were observed in sintered samples at 1350 oC.

Influences of Firing Temperatures on Phase and Morphology Evolution of (Ba0.25Sr0.75)(Zr0.75Ti0.25)O3 Ceramics Synthesized via Solid-State Reaction Method

2009 ◽  
Vol 421-422 ◽  
pp. 247-250 ◽  
Author(s):  
Atthakorn Thongtha ◽  
Kritsana Angsukased ◽  
Theerachai Bongkarn
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Perovskite Phase ◽  
Average Particle Size ◽  
Solid State Reaction Method ◽  
Lattice Parameter ◽  
Average Particle ◽  
Strontium Zirconate ◽  
Reaction Method ◽  
Average Grain Size

The effect of calcination (1000-1400 oC) and sintering temperatures (1400-1600 oC) on the phase formation and microstructure of barium strontium zirconate titanate [(Ba0.25Sr0.75)(Zr0.75Ti0.25)O3; BSZT] ceramics were investigated. BSZT powders were prepared by the solid-state reaction method. Higher calcination temperatures increased the percentage of the perovskite phase, but decreased the lattice parameter a of BSZT powders. The pure perovskite phase of BSZT powders was detected above the calcination temperature of 1350 oC. The microstructure of BSZT powders exhibited an almost-spherical morphology and had a porous agglomerated form. The average particle size and the average grain size of the ceramics were increased with the increase of calcination and sintering temperatures. The highest density of the samples was 5.42 g/cm3 which was obtained from ceramic sintered at 1550 oC for 2 h.

scholarly journals Lattice parameters and site occupancy factors of magnetite–maghemite core–shell nanoparticles. A critical study

2014 ◽  
Vol 47 (5) ◽  
pp. 1755-1761 ◽  
Author(s):  
Antonio Cervellino ◽  
Ruggero Frison ◽  
Giuseppe Cernuto ◽  
Antonietta Guagliardi ◽  
Norberto Masciocchi
Keyword(s):  
Site Occupancy ◽  
Lattice Parameter ◽  
Lattice Parameters ◽  
Critical Study ◽  
Core Shell ◽  
Large Set ◽  
Shell Nanoparticles ◽  
Debye Function ◽  
Sample Average ◽  
Core Shell Nanoparticles

The size-driven expansion and oxidation-driven contraction phenomena of nonstoichiometric magnetite–maghemite core–shell nanoparticles have been investigated by the total scattering Debye function approach. Results from a large set of samples are discussed in terms of significant effects on the sample average lattice parameter and on the possibility of deriving the sample average oxidation level from accurate, diffraction-based, cell values. Controlling subtle experimental effects affecting the measurement of diffraction angles and correcting for extra-sample scattering contributions to the pattern intensity are crucial issues for accurately estimating lattice parameters and cation vacancies. The average nanoparticle stoichiometry appears to be controlled mainly by iron depletion of octahedral sites. A simple law with a single adjustable parameter, well correlating lattice parameter, stoichiometry and size effects of all the nanoparticles present in the whole set of samples used in this study, is proposed.

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