Pengaruh Pemanasan Terhadap Kristalinitas Dan Parameter Kisi Nanokomposit Silika-Zirkonia Montmorillonit K10  Dan Silika-Besi Oksida Montmorillonit K10

The thermal treatment of the silica-zirconia montmorillonite K10 and silica-ferri oxide montmorillonite K10 nanocomposites at 300 and 500 °C has been carried out, respectively as part of a study of their function as the catalyst. The heating effect on the crystallinity and the lattice parameter calculation of both nanocomposites was studied using XRD and FTIR instruments. The results showed that the nanocomposite silica-zirconia montmorillonite K10 has a thermal resistance and the crystallinity better than the silica-ferri oxide montmorillonite K10, and both have values varying lattice parameters.

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DFT and TB-mBJLDA studies of structural, electronic and optical properties of Hg1-xCdxTe and Hg1-xZnxTe

Revista Mexicana de Física ◽

10.31349/revmexfis.67.061003 ◽

2021 ◽

Vol 67 (6 Nov-Dec) ◽

Author(s):

N. Aouail ◽

M. Noureddine Belkaid ◽

A. Oukebdane ◽

M. Hocine Tedjini

Keyword(s):

Optical Properties ◽

Dielectric Function ◽

Optical Constants ◽

Lattice Parameter ◽

Lattice Parameters ◽

Experimental Results ◽

Gap Energy ◽

Better Than ◽

Good Agreement ◽

Semiconductor Properties

In this paper, the fundamental semiconductor properties of Hg1-xCdxTe and Hg1-xZnxTe are investigated by ab initio calculations based on the FP-LAPW method. Structural properties have been calculated using LDA and GGA approximations. The electronic properties are studied using the LDA and GGA approximations, and the potential TB-mBJLDA coupled with the lattice parameters aLDA and aGGA. The optical properties are determined from the optimal gap energies based on the TB-mBJLDA potential. Lattice parameters aLDA obtained by the LDA calculations predict values that are in good agreement with the experimental results and are better than those results obtained by the GGA calculations. The use of TB-mBJLDA potential coupled with the lattice parameter aGGA gives gap energy values in good agreement with the experimental results for all alloys except Hg1-xZnxTe (x=0.5, 0.75) where the (TB-mBJ LDA+aLDA) is more suitable. Optical constants are calculated from the dielectric function in the energy range (0-30 eV). The spectrum of real and imaginary parts of the dielectric function, the energy loss function, the refractive index, the extinction coefficient, the absorption coefficient, and the reflectivity show that optical properties of Hg1-xCdxTe are comparable to those of Hg1-xZnxTe. Our results are found to be in reasonable agreement with existing data reported in the literature.

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On the impact of lattice parameter accuracy of atomistic simulations on the microstructure of Ni-Ti shape memory alloys

Modelling and Simulation in Materials Science and Engineering ◽

10.1088/1361-651x/ac3b9e ◽

2021 ◽

Author(s):

Lorenzo La Rosa ◽

Francesco Maresca

Keyword(s):

Molecular Dynamics ◽

Shape Memory Alloys ◽

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Lattice Parameter ◽

Lattice Parameters ◽

Atomistic Simulations ◽

Interatomic Potentials ◽

The Impact

Abstract Ni-Ti is a key shape memory alloy (SMA) system for applications, being cheap and having good mechanical properties. Recently, atomistic simulations of Ni-Ti SMAs have been used with the purpose of revealing the nano-scale mechanisms that control superelasticity and the shape memory effect, which is crucial to guide alloying or processing strategies to improve materials performance. These atomistic simulations are based on molecular dynamics modelling that relies on (empirical) interatomic potentials. These simulations must reproduce accurately the mechanism of martensitic transformation and the microstructure that it originates, since this controls both superelasticity and the shape memory effect. As demonstrated by the energy minimization theory of martensitic transformations [Ball, James (1987) Archive for Rational Mechanics and Analysis, 100:13], the microstructure of martensite depends on the lattice parameters of the austenite and the martensite phases. Here, we compute the bounds of possible microstructural variations based on the experimental variations/uncertainties in the lattice parameter measurements. We show that both density functional theory and molecular dynamics lattice parameters are typically outside the experimental range, and that seemingly small deviations from this range induce large deviations from the experimental bounds of the microstructural predictions, with notable cases where unphysical microstructures are predicted to form. Therefore, our work points to a strategy for benchmarking and selecting interatomic potentials for atomistic modelling of shape memory alloys, which is crucial to modelling the development of martensitic microstructures and their impact on the shape memory effect.

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Monocarbide Characterization In Nickel-Base Mc Aligned Eutectics

MRS Proceedings ◽

10.1557/proc-12-155 ◽

1981 ◽

Vol 12 ◽

Author(s):

M.R. Jackson ◽

M.F.X. Gigliotti ◽

S.W. Yang ◽

J.L. Walter

Keyword(s):

Chemical Analysis ◽

Lattice Parameter ◽

Lattice Parameters ◽

Quantitative Chemical Analysis ◽

Eutectic Alloys ◽

Free Energies ◽

Jet Engine ◽

Engine Blade ◽

Nickel Base ◽

Quantitative Chemical

ABSTRACTIn the aligned Ni-MC eutectic alloys being developed for jet engine blade applications, the fibers are considered to be Tac, Tic, etc. In fact, these fibers will contain Cr, Mo, W and possibly other elements as substitutions for the “M” constituent, and often will not be stoichiometric. Quantitative chemical analysis of fibers is difficult because of their size. However, lattice parameter measurements can be used to learn much a out the carbide chemistry and stoichiometry. Results will be described in detail for fibers extracted from simple Ni-TaC, Ni,Cr-TaC and Ni,Cr,AI-Tac systems. In addition, experiments on mixed (Ta,V)C and (Ta,Ti)C carbides will be discussed. Carbide lattice parameters can be understood in terms of the free energies of formation of the various carbides.

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Leach Resistant Cesium and Strontium-bearing Wasteforms from Hexagonal Tungsten Bronze-Polyacrylonitrile Composite Adsorbers

MRS Proceedings ◽

10.1557/proc-932-57.1 ◽

2006 ◽

Vol 932 ◽

Author(s):

Christopher S. Griffith ◽

Vittorio Luca ◽

Ferdinand Sebesta ◽

Patrick Yee ◽

Elizabeth Drabarek

Keyword(s):

Composite Material ◽

Thermal Treatment ◽

Strontium Titanate ◽

Tungsten Bronze ◽

Composite Adsorbent ◽

Spherical Morphology ◽

Sodium Cations ◽

Full Complement ◽

High Concentrations ◽

Better Than

ABSTRACTImmobilization of adsorbed Cs+ and Sr2+ on a molybdenum-doped, hexagonal tungsten bronze (HTB)-polyacrylonitrile (PAN) composite adsorbent can be achieved by heating in air at temperatures in the range 600 - 1200 °C. Thermal treatment of the parent composite material at 800 – 1000 °C undergoes a ca. 60% reduction in volume and retains its spherical morphology. For materials prepared at 800 – 1200 °C the full complement of Cs+ and the majority of Sr2+ partition into HTB phases (A∼0.16-0.3MO3; A = Cs, Sr, Na; M = Mo,W), along with sodium cations. The presence of high concentrations of Na+ relative to either Cs+ or Sr2+ does not appear to interfere with the formation of the HTB phase. The fraction (f) of Cs+ and Sr2+ leached from the tungstate phase assemblages is better or comparable with cesium hollandite (Cs0.8Ba0.4Ti8O18; f = ca. 8 × 10−5; rate = <1.2 × 10−4 g m−2d−1) and strontium titanate (SrTiO3; f = 3.1 × 10−3; rate = 2.63 × 10−4 g m−2day−1), respectively, using a modified PCT test. Furthermore, where aggressive leaching conditions are employed (0.1M HNO3; 150 °C; 4 days), the tungstate phase assemblages display leach resistance orders of magnitude better than the reference phases (Cs+ - f = ca. 5 × 10−3; rate = ca. 1.4 × 10−3 g m−2day−1; Sr2+ - f = ca. 8 × 10−2; rate = ca. 2.5 × 10−2 g m−2day−1).

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Precision Lattice Parameter Determination at Liquid Helium Temperatures by Double-Scanning Diffractometry

Advances in X-ray Analysis ◽

10.1154/s0376030800004523 ◽

1966 ◽

Vol 10 ◽

pp. 354-365 ◽

Cited By ~ 7

Author(s):

Hubert W. King ◽

Carolyn M. Preece

Keyword(s):

Liquid Helium ◽

Lattice Parameter ◽

Lattice Parameters ◽

Parameter Determination ◽

Double Scanning ◽

Cryogenic Temperatures ◽

Included Angle ◽

X Ray ◽

Standard Specimens ◽

Alignment Errors

AbstractThe back-reflect ion double-scanning diffractometer method, by which lattice parameters can be measured with a reproducibility of one part in 150,000 has been applied at liquid helium temperatures. A cryostat attachment is described which enables diffraction profiles to be scanned on both sides of the primary X-ray beam up to 163°, 2θ. Alignment errors may, thus, be eliminated by measuring the included angle 4θ between respective Bragg reflections. The method is illustrated by measuring the lattice parameters of the I.U.Cr. standard specimens of silicon and tungsten at various cryogenic temperatures.

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The thermal decomposition of chrysotile

Mineralogical Magazine ◽

10.1180/minmag.1977.041.320.05 ◽

1977 ◽

Vol 41 (320) ◽

pp. 453-459 ◽

Cited By ~ 24

Author(s):

C. J. Martin

Keyword(s):

Electron Microscopy ◽

Thermal Decomposition ◽

Thermal Treatment ◽

High Temperatures ◽

Lattice Parameters ◽

Atomic Arrangement ◽

Observable Change ◽

Infra Red ◽

Magnesium Silicates

SummaryThe decomposition of chrysotile fibres heated in air has been studied in the range 100–1400°C by electron microscopy and infra-red absorption. The first observable change in the structure occurred at 580°C, where cavities started to open up between the (001) layers of chrysotile as the fibres were dehydrated, giving rise to strong low-angle diffraction. There was no evidence of any structure in the remaining material but some degree of the original atomic arrangement was preserved for the magnesium silicates, forsterite, and enstatite, later developed in certain preferred orientations. The manner of this crystallization was determined by the thermal treatment, for in samples held between 600°C and 800°C forsterite developed slowly with little further disruption of the fibre while above 800°C the remaining amorphous areas rapidly recrystallized to a mixture of forsterite and enstatite. It is suggested that the mechanisms described by other investigators to explain the development of forsterite in preferred orientations may serve simply to nucleate the crystallization and a similar mechanism to account for the nucleation of the enstatite crystallization is considered. At high temperatures a possible doubling of some of the lattice parameters of the silicates was observed.

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X-ray diffractometry studies and lattice parameter calculation on KNO3–NH4NO3 solid solutions

Powder Diffraction ◽

10.1154/1.1913718 ◽

2005 ◽

Vol 20 (02) ◽

pp. 101-104 ◽

Cited By ~ 1

Author(s):

Wen-Ming Chien ◽

Dhanesh Chandra ◽

Jennifer Franklin ◽

Claudia J. Rawn ◽

Abdel K. Helmy

Keyword(s):

Solid Solutions ◽

Lattice Parameter ◽

X Ray ◽

Parameter Calculation

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Effects of Thermal Treatment on the Structure of Eu:YAG Nanopowder

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.128.107 ◽

2007 ◽

Vol 128 ◽

pp. 107-114 ◽

Cited By ~ 4

Author(s):

Maria Luisa Saladino ◽

Eugenio Caponetti ◽

Stefano Enzo

Keyword(s):

Thermal Treatment ◽

Lattice Strain ◽

Rietveld Method ◽

Lattice Parameter ◽

Spherical Particles ◽

X Rays ◽

Garnet Phase ◽

The Matrix ◽

Different Temperatures ◽

Co Precipitation

Eu:YAG nanopowder precursors were obtained by co-precipitation of aluminium, yttrium and europium nitrates solution with ammonia. The hydroxides precursors were calcined at different temperatures from 900 to 1200°C as a function of holding time (1, 2 and 6 hours). The presence of Eu3+ ions in the matrix was confirmed by Energy Dispersive X-rays analysis. X-Ray Diffraction investigation by the Rietveld method shows that the sample treated at 900°C for 1 hour is essentially the garnet phase with the minor presence of hexagonal and monoclinic metastable phases. The Eu3+ ions are incorporated into the garnet phase, as is suggested by the lattice parameter value being larger than that in literature data (homogeneous strain). For the sample treated at 900°C for 1 hour, electron microscopy observations showed agglomerates of spherical particles of mean size about 50 nm. At higher temperature treatments and for longer holding times the minority hexagonal and monoclinic phases totally disappeared. However, the lattice parameters of the cubic garnet phase gradually decreased with temperature, suggesting an expulsion of Eu3+ ions from the solid solution. Simultaneous with this, it was noted that the lattice strain reached a maximum value, but to later decrease, due to the vacancies created by the Eu species initially migrating to the surface of the coherent domains of diffraction. The lattice strain definitely decreased upon more drastic thermal treatments. Meanwhile, FEG-SEM and TEM observations on the same samples confirmed the growth of the garnet particles as a function of the thermal treatment.

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Preparation and Structure Analysis of Noncrystalline Granular Starch

International Journal of Food Engineering ◽

10.2202/1556-3758.1900 ◽

2010 ◽

Vol 6 (4) ◽

Cited By ~ 11

Author(s):

Peiling Liu ◽

Benshan Zhang ◽

Qun Shen ◽

Xiaosong Hu ◽

Wenhao Li

Keyword(s):

Thermal Treatment ◽

Crystalline Structure ◽

Chemical Method ◽

Physical Method ◽

Maize Starch ◽

X Ray Diffraction ◽

Preparation Methods ◽

Peculiar Form ◽

Freeze Dried ◽

Better Than

Noncrystalline granular (NCG) starch is a peculiar form of starch. The granules have granular shape but no crystalline structure. It is a middle state between native semi-crystal structure and paste. The conception of NCG starch was presented and its preparation methods for native maize starch were explored. Cross-linking by chloroepoxy propane was adopted as the chemical method while ethanol treatment was adopted as the physical method. Cross bonds and ethanol were both able to protect starch granules from swelling while thermal treatment was able to destroy crystalline structure of the granules. The structure of granule was observed by polarization microscope and scanning electron microscopy (SEM). Change from crystalline to noncrystalline structure was confirmed by X-ray diffraction (XRD). It indicated that preparation of NCG starch with the physical method was better than chemical method. The detailed conditions were: maize starch (40%, w/w) was slurried in 50%-ethanol, underwent thermal treatment at 85°C for 2 minutes, washed with anhydrous ethanol (2000 ml), and freeze dried.

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