scholarly journals Comment on “Crystal growth and aggregation in suspensions of δ-MnO2 nanoparticles: implications for surface reactivity” by F. F. Marafatto, B. Lanson and J. Peña, Environ. Sci.: Nano, 2018, 5, 497

2018 ◽  
Vol 5 (9) ◽  
pp. 2198-2200 ◽  
Author(s):  
Alain Manceau
Keyword(s):  
Crystal Growth ◽  
Crystallite Size ◽  
Strain Gradient ◽  
Lognormal Distribution ◽  
Surface Reactivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mno2 Nanoparticles

We show that X-ray diffraction of δ-MnO2 nanoparticles is sensitive to the lognormal distribution of the crystallite size and to the strain gradient across the nanosheet.

scholarly journals Crystal growth and aggregation in suspensions of δ-MnO2 nanoparticles: implications for surface reactivity

2018 ◽  
Vol 5 (2) ◽  
pp. 497-508 ◽  
Author(s):  
Francesco Femi Marafatto ◽  
Bruno Lanson ◽  
Jasquelin Peña
Keyword(s):  
Crystal Growth ◽  
Crystallite Size ◽  
Ph Control ◽  
Sodium Content ◽  
Surface Reactivity ◽  
Mno2 Nanoparticles ◽  
Suspension Ph

Sodium content and suspension pH control crystallite size and aggregation in δ-MnO2 nanoparticles.

Mechanochemical Synthesis of Zinc Ferrite, ZnFe2O4

2007 ◽  
Vol 534-536 ◽  
pp. 201-204
Author(s):  
Yutaka Sawada ◽  
Kiyokata Iizumi ◽  
Tomokazu Kuramochi ◽  
Mei Han Wang ◽  
Li Xian Sun ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Crystallite Size ◽  
Powder Mixture ◽  
Mechanochemical Synthesis ◽  
Zinc Ferrite ◽  
Diffraction Spectrum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Milled Powders

Mechanochemical synthesis of zinc ferrite, ZnFe2O4, was attempted from a powder mixture of iron (III) oxide, alpha-Fe2O3 and zinc (II) oxide, ZnO. Nanocrystalline zinc ferrite, ZnFe2O4 powders were successfully synthesized only by milling for 30 hours. The X-ray diffraction spectrum of the as-milled powders (without heating) showed twelve ZnFe2O4 peaks and four weak peaks of coexisting unreacted Fe2O3. The crystallite size of the mechanochemicallysynthesized ZnFe2O4 was 26.3 nm. Evidence of the ZnFe2O4 formation was absent for the powders milled for 10 and 20 hours; milling lowered the crystallinity of the starting materials. Heating after milling enhanced the formation of ZnFe2O4, the crystal growth of ZnFe2O4 and the unreacted starting materials. The unreacted starting materials decreased their amounts by heating at higher temperatures.

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.

scholarly journals Measurements by x-ray diffraction of the temperature dependence of lattice parameter and crystallite size for isostatically-pressed graphite

Carbon Trends ◽  
2021 ◽  
pp. 100071
Author(s):  
Keith R. Hallam ◽  
James Edward Darnbrough ◽  
Charilaos Paraskevoulakos ◽  
Peter J. Heard ◽  
T. James Marrow ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Crystallite Size ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Synthesis of magnesium carbonate hydrate from natural talc

2020 ◽  
Vol 18 (1) ◽  
pp. 951-961
Author(s):  
Qiuju Chen ◽  
Tao Hui ◽  
Hongjuan Sun ◽  
Tongjiang Peng ◽  
Wenjin Ding
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Crystal Growth ◽  
Crystal Morphology ◽  
Magnesium Carbonate ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
Morphological Transformation ◽  
X Ray ◽  
Carbonation Process

AbstractVarious morphologies of magnesium carbonate hydrate had been synthesized without using any organic additives by carefully adjusting the reaction temperature and time during the talc carbonation process. At lower temperatures, magnesium carbonate hydrate was prone to display needle-like morphology. With the further increase of the carbonation temperature, the sheet-like crystallites became the preferred morphology, and at higher aging temperatures, these crystallites tended to assemble into layer-like structures with diverse morphologies, such as rose-like particles and nest-like structure. The reaction time had no effect on the crystal morphology, but it affected the particle size and situation of the crystal growth. X-Ray diffraction results showed that these various morphologies were closely related to their crystal structure and compositions. The needle-like magnesium carbonate hydrate had a formula of MgCO3·3H2O, whereas with the morphological transformation from needle-like to sheet-like, rose-like, and nest-like structure, their corresponding compositions also changed from MgCO3·3H2O to 4MgCO3·Mg(OH)2·8H2O, 4MgCO3·Mg(OH)2·5H2O, and 4MgCO3·Mg(OH)2·4H2O.

The Use of the Pseudo-Voigt Function in the Variance Method of X-ray Line-Broadening Analysis

1997 ◽  
Vol 30 (4) ◽  
pp. 427-430 ◽  
Author(s):  
F. Sánchez-Bajo ◽  
F. L. Cumbrera
Keyword(s):  
Crystallite Size ◽  
Original Form ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Variance Method ◽  
The Mean ◽  
Voigt Function

A modified application of the variance method, using the pseudo-Voigt function as a good approximation to the X-ray diffraction profiles, is proposed in order to obtain microstructural quantities such as the mean crystallite size and root-mean-square (r.m.s.) strain. Whereas the variance method in its original form is applicable only to well separated reflections, this technique can be employed in the cases where there is line-profile overlap. Determination of the mean crystallite size and r.m.s. strain for several crystallographic directions in a nanocrystalline cubic sample of 9-YSZ (yttria-stabilized zirconia) has been performed by means of this procedure.

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