X-Ray Diffraction Analysis of the Calcium Carbonate Polymorphs

1970 ◽  
Vol 14 ◽  
pp. 29-37 ◽  
Author(s):  
S. T. Silk ◽  
S. Z. Lewin
Keyword(s):  
Calcium Carbonate ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Particle Size Distributions ◽  
Ray Method ◽  
X Ray ◽  
Packing Efficiency ◽  
Integrated Intensities ◽  
Packing Effect ◽  
Calcium Carbonate Polymorphs

AbstractIt is shown that the integrated intensities of diffraction lines from calcite and aragonite powders prepared by precipitation vary markedly, due to variations in sample packing efficiency arising from different degrees of polydispersity in the particle size distributions. Since prolonged grinding to equalize initially divergent distributions changes the polymorph composition, the packing effect imposes the principal limitation on the precision of the x-ray method for certain types of calcium carbonate preparations.

Phase and Particle Size Analysis of SnO2 Nanomaterials

2015 ◽  
Vol 1109 ◽  
pp. 314-318
Author(s):  
Nor Diyana Abdul Aziz ◽  
Kelimah Elong ◽  
Norlida Kamarulzaman
Keyword(s):  
Particle Size ◽  
Particle Size Analysis ◽  
Annealed Sample ◽  
Degree Of Crystallinity ◽  
Size Analysis ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Particle Size Distributions ◽  
X Ray ◽  
Particle Sizer

Tin Oxide (SnO2) is a metal oxide which has many applications in industry. In this study, SnO2 powders were synthesized by a self-propagating combustion (SPC) method. The product was annealed at 800 °C for 12 and 24 h before characterizing with X-Ray Diffraction (XRD) for phase studies. X-Ray Diffraction results showed that both samples are pure of tetragonal structure with space group P42/mnm. The sample annealed at a longer period, that is, 24 h, shows a higher degree of crystallinity compared to the 12 h annealed sample. It also shows a smaller full width at half maximum (FWHM), indicating larger crystallite size for the 24 h annealed sample. The particle size analysis reveals that there are two groups of particle size distributions for both samples. SEM results give values that are different from the particle sizer results due to the different nature of the measurement methods.

Textured Coatings from Colloidal Suspensions of Faceted Oxide Microcrystals

1992 ◽  
Vol 286 ◽  
Author(s):  
Gregg.W. Steadman ◽  
J. R. Brewster ◽  
J. D. Budai ◽  
L. A. Boatner
Keyword(s):  
Particle Size ◽  
Colloidal Suspensions ◽  
Fiber Texture ◽  
Preferred Orientation ◽  
Morphological Properties ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Particle Size Distributions ◽  
X Ray ◽  
Flat Substrate

ABSTRACTThe morphological properties of cubic, faceted MgO microcrystals have been exploited in the formation of textured coatings. Coatings exhibiting a <100> “fiber” texture were formed by centrifugal sedimentation of colloidal suspensions onto a flat substrate. A decrease in the degree of preferred orientation in the coatings with increasing areal coverage of the particles was quantified for several particle-size distributions by using x-ray diffraction. Novel methods for the deposition of particles exhibiting an in-plane preferred orientation in addition to fiber texture have been investigated.

A Micro-Raman Study of Niobium Titanium Oxide Powders Obtained by Laser-Induced Synthesis

1996 ◽  
Vol 454 ◽  
Author(s):  
L. E. Depero ◽  
L. Sangaletti ◽  
E. Bontempi ◽  
R. Salari ◽  
C. Casale ◽  
...  
Keyword(s):  
Rutile Phase ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Particle Size Distributions ◽  
X Ray ◽  
Oxide Powders ◽  
Nb Content ◽  
Different Temperatures ◽  
Raman Study ◽  
Diffraction Patterns

ABSTRACTMicroraman and scanning electron microscopy studies have been performed on pure TiO2 and Nb-Ti-O nanopowders obtained by laser induced synthesis. The effect of Nb content on the temperature of the anatase to rutile phase transformation, induced by annealing in air at different temperatures, has been evidenced and related to the changes in the particle size distributions obtained from a Fourier analysis of the X-ray diffraction patterns.

Effect of Annealing on Microstructure and Properties of Al-Ti Multilayered Films

1999 ◽  
Vol 594 ◽  
Author(s):  
R. Mitra ◽  
A. Madan ◽  
R. A. Hoffman ◽  
W. A. Chiou ◽  
J. R. Weertman
Keyword(s):  
Cross Section ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
Particle Size Distributions ◽  
Multilayered Films ◽  
Plan View ◽  
X Ray ◽  
Ti Particles ◽  
Deposited Films ◽  
Ti Films

AbstractAl-Ti multilayered films were deposited by magnetron sputtering of Al and Ti targets on to Si (100) or NaCl substrates. The bi-layer thickness was 16 nm with Ti constituting 12% of the total thickness. The films were subsequently annealed in vacuum at 400°C for periods between 2 and 24 h. In the course of the annealing, interdiffusion and chemical reaction between Al and Ti layers led to the precipitation of Al3Ti particles. Plan view and cross-section TEM examination of as-deposited and annealed films were performed to study the microstructural evolution, and to estimate the Al grain and AI3Ti particle size distributions. Cross-section TEM and X-ray diffraction showed a well-defined layered structure in the as-deposited films. The microstructure was found to be metastable in the first 6 h of annealing, with Al-Ti multilayers being gradually replaced by an AI-AI3Ti composite structure. The Al3Ti particles were uniformly distributed throughout the film. X-ray and electron diffraction analyses showed that Al3Ti possessed the ordered DO22 structure. The hardness of the Al-Ti films in as-deposited and annealed conditions was determined using a nanoindenter and the data have been correlated with the microstructural changes with annealing.

Influence of the Type of Cement on the Formation of Calcium Carbonate Polymorphs due to Carbonation of Cement Materials

2014 ◽  
Vol 529 ◽  
pp. 49-53
Author(s):  
Son Tung Pham ◽  
William Prince
Keyword(s):  
Calcium Carbonate ◽  
Thermogravimetric Analysis ◽  
Relative Humidity ◽  
Accelerated Carbonation ◽  
X Ray Diffraction ◽  
Advanced Level ◽  
X Ray ◽  
Calcium Carbonate Polymorphs

The objective of this study was to examine the influence of the type of cement on the formation of calcium carbonate CaCO3 polymorphs after carbonation of cement materials. Thermogravimetric analysis and X-ray diffraction were used to follow mineralogical changes of CEM I and CEM II mortars and pastes which were submitted to an accelerated carbonation at 20% CO2, 20°C and 65% relative humidity. The results indicated that aragonite and vaterite are formed from the carbonation of CEM II materials while these metastable polymorphs are not present in carbonated CEM I materials. It is likely that aragonite and vaterite are formed only at an advanced level of carbonation when pH is smaller than 9, which is the case of CEM I mortar and paste.

Effects of Rotation Speeds and Media Density on Ground Calcium Carbonate during Ultrafine Grinding Process in Planetary Mill

2014 ◽  
Vol 997 ◽  
pp. 542-545
Author(s):  
Yan Ru Chen ◽  
Yi Chen Lu ◽  
Xiao Min Lian ◽  
Chao Yang Li ◽  
Shui Lin Zheng
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Rotational Speed ◽  
Planetary Mill ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dry Grinding ◽  
Ultrafine Grinding ◽  
Effects Of Rotation ◽  
Ground Calcium Carbonate

Superfine ground calcium carbonate (GCC) produced by carbonate minerals is a widely used inorganic powder material. In order to get a finer GCC powder with narrow distribution span, the effect of rotational speed and media density on ground GCC were studied by dry grinding GCC in a planetary ball mill under different rotational speed and various media density. The grinding limit-particle size and distribution of grinding calcium carbonate were measured by centrifugal sedimentation granulometer. The structure of GCC was measured by X-ray diffraction. The result shows that low rotational speed and high-density media is conducive to get a product with smaller particle size and narrow size distribution; crystal plane (012) and (122) are more stable than (018) and (116).

Synthesis of Precipitate Calcium Carbonate with Variation Morphology from Limestone by Using Solution Mixing Method

2019 ◽  
Vol 966 ◽  
pp. 200-203
Author(s):  
Zaenal Arifin ◽  
Triwikantoro ◽  
Bintoro Anang Subagyo ◽  
Mochamad Zainuri ◽  
Darminto
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Molar Ratio ◽  
Mixing Process ◽  
X Ray Diffraction ◽  
Precipitate Calcium Carbonate ◽  
X Ray ◽  
Mixing Method ◽  
Scanning Electron

Abstract. In this study, the CaCO3 powder has been successfully synthesized by mixing CaCl2 from natural limestone and Na2CO3 in the same molar ratio. The mixing process of solutions was carried out by employing the molar contents of 0.125, 0.25, 0.375 and 0.5M at varying temperatures of 30, 40, 60 and 80ᴼC. The produced CaCO3 microparticles were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The highest content of aragonite phase with morphology rod-like of the samples is around 29 wt%, resulting from the process using solution of 0.125 M at 80 ᴼC. While at 30 ᴼC and 40 ᴼC produced 100 wt% calcite phase.

scholarly journals X-Ray Dynamical Diffraction in Powder Samples with Time-Dependent Particle Size Distributions - ADDENDUM

MRS Advances ◽  
2020 ◽  
Vol 5 (29-30) ◽  
pp. 1623-1623
Author(s):  
Adriana Valério ◽  
Sérgio L. Morelhão ◽  
Alex J. Freitas Cabral ◽  
Márcio M. Soares ◽  
Cláudio M. R. Remédios
Keyword(s):  
Particle Size ◽  
Time Dependent ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Dynamical Diffraction ◽  
X Ray ◽  
Powder Samples

scholarly journals Luminescence reveals variations in local structural order of calcium carbonate polymorphs formed by different mechanisms

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Michael B. Toffolo ◽  
Giulia Ricci ◽  
Luisa Caneve ◽  
Ifat Kaplan-Ashiri
Keyword(s):  
Infrared Spectroscopy ◽  
Calcium Carbonate ◽  
Construction Materials ◽  
Reference Database ◽  
Formation Processes ◽  
X Ray Diffraction ◽  
Structural Order ◽  
Lime Plaster ◽  
Calcium Carbonate Polymorphs

Abstract In nature, calcium carbonate (CaCO3) in the form of calcite and aragonite nucleates through different pathways including geogenic and biogenic processes. It may also occur as pyrogenic lime plaster and laboratory-precipitated crystals. All of these formation processes are conducive to different degrees of local structural order in CaCO3 crystals, with the pyrogenic and precipitated forms being the least ordered. These variations affect the manner in which crystals interact with electromagnetic radiation, and thus formation processes may be tracked using methods such as X-ray diffraction and infrared spectroscopy. Here we show that defects in the crystal structure of CaCO3 may be detected by looking at the luminescence of crystals. Using cathodoluminescence by scanning electron microscopy (SEM-CL) and laser-induced fluorescence (LIF), it is possible to discern different polymorphs and their mechanism of formation. We were thus able to determine that pyrogenic calcite and aragonite exhibit blue luminescence due to the incorporation of distortions in the crystal lattice caused by heat and rapid precipitation, in agreement with infrared spectroscopy assessments of local structural order. These results provide the first detailed reference database of SEM-CL and LIF spectra of CaCO3 standards, and find application in the characterization of optical, archaeological and construction materials.

scholarly journals Integration techniques for surface X-ray diffraction data obtained with a two-dimensional detector

2014 ◽  
Vol 47 (1) ◽  
pp. 365-377 ◽  
Author(s):  
Jakub Drnec ◽  
Tao Zhou ◽  
Stelian Pintea ◽  
Willem Onderwaater ◽  
Elias Vlieg ◽  
...  
Keyword(s):  
Reciprocal Space ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Integration Methods ◽  
X Ray ◽  
Structure Factors ◽  
Integration Techniques ◽  
Intensity Map ◽  
Integrated Intensities ◽  
Surface Diffraction

This article proposes two integration methods to determine the structure factors along a surface diffraction rod measured with a two-dimensional detector. The first method applies the classic way of calculating integrated intensities in angular space. This is adapted to work efficiently with two-dimensional data. The second method is based on integration in reciprocal space. An intensity map is created by converting the detected intensity pixel by pixel to the reciprocal space. The integration is then performed directly on this map. A theoretical framework, as well as a comparison between the two integration methods, is provided.

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