Mechanism of Solid-State Amorphization in the Fe-Si-Cu-Mg-O System

2021 ◽  
Vol 316 ◽  
pp. 295-299
Author(s):  
Nikolai N. Nikul'chenkov ◽  
Andrey A. Redikul'tsev ◽  
Mikhail L. Lobanov
Keyword(s):  
Solid Solution ◽  
Solid State ◽  
Amorphous State ◽  
Continuous Annealing ◽  
X Ray Diffraction ◽  
Transformation Temperatures ◽  
X Ray ◽  
Heating And Cooling ◽  
Cu Alloy ◽  
State Amorphization

Solid-state amorphization process occurring at 600-1060 °C continuous annealing was observed by non-ambient x-ray diffraction on Fe-3%Si-0.5%Cu alloy surface with MgO as thermostable coating. The phenomenon was occurred at α→γ transformation temperatures (920-960 °C) in a layer consisting of Si solid solution in α-Fe and oxides (MgFe)2SiO4, (MgFe)O, SiO2. Amorphous state remained both during heating and cooling to 20 °C. Simulation for diffusion amorphization of Fe (Si) solid solution was proposed. Mg2Si complexes are reduced from oxides by hydrogen then transfer to solid solution and solid-state amorphization is occurred.

SOLID STATE AMORPHIZATION IN MECHANICALLY ALLOYED Al–Ti–Si NANOCOMPOSITES

2005 ◽  
Vol 04 (05n06) ◽  
pp. 1025-1028
Author(s):  
I. MANNA ◽  
P. NANDI ◽  
B. BANDYOPADHYAY ◽  
P. M. G. NAMBISSAN ◽  
K. GHOSHRAY ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Amorphous Solid ◽  
Positron Annihilation Spectroscopy ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
X Ray ◽  
Transmission Electron ◽  
State Amorphization

The microstructural evolution at different stages of milling of a ternary powder blend of Al 50 Ti 40 Si 10 composition was monitored by X-ray diffraction, high-resolution transmission electron microscopy, positron annihilation spectroscopy and 27 Al nuclear magnetic resonance. Ball-milling leads to alloying, nanocrystallization and partial solid state amorphization, either followed or accompanied by strain-induced nucleation of nanocrystalline intermetallic phases from an amorphous solid solution.

Rietveld refinements of a new solid solution Ba(3−x)Srx(PO4)2 (0≤x≤3)

2003 ◽  
Vol 18 (2) ◽  
pp. 122-127 ◽  
Author(s):  
B. Manoun ◽  
L. Popović ◽  
D. De Waal ◽  
S. M. C. Verryn
Keyword(s):  
Solid Solution ◽  
Solid State ◽  
Solid State Reaction ◽  
Continuous Solid Solution ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Final Temperature ◽  
Hexagonal System ◽  
Rietveld Refinements ◽  
X Ray

Ba(3−x)Srx(PO4)2 orthophosphates (0≤x≤3) have been prepared by solid state reaction. The final temperature was 1000°C. The X-ray diffraction analyses show the existence of a continuous solid solution. Ba(3−x)Srx(PO4)2 orthophosphates (0≤x≤3) crystallize in the hexagonal system with the space group R3m. Their structure is based on a three-dimensional framework constructed of infinite layers of Ba1/Sr1O12 linked and parallel to infinite layers of Ba2/Sr2O10 polyhedra and PO4 tetrahedra.

scholarly journals Methods of amorphization and investigation of the amorphous state

2013 ◽  
Vol 63 (3) ◽  
pp. 305-334 ◽  
Author(s):  
Tomaž Einfalt ◽  
Odon Planinšek ◽  
Klemen Hrovat
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Infrared Spectroscopy ◽  
Solid State ◽  
Terahertz Spectroscopy ◽  
Amorphous State ◽  
Amorphous Form ◽  
X Ray ◽  
State Amorphization ◽  
Crystalline Hydrates ◽  
And Calorimetry

Abstract The amorphous form of pharmaceutical materials represents the most energetic solid state of a material. It provides advantages in terms of dissolution rate and bioavailability. This review presents the methods of solid- -state amorphization described in literature (supercooling of liquids, milling, lyophilization, spray drying, dehydration of crystalline hydrates), with the emphasis on milling. Furthermore, we describe how amorphous state of pharmaceuticals differ depending on the method of preparation and how these differences can be screened by a variety of spectroscopic (X-ray powder diffraction, solid state nuclear magnetic resonance, atomic pairwise distribution, infrared spectroscopy, terahertz spectroscopy) and calorimetry methods.

Comparison of Solvent-Casting and Melt-Compounding Blended Biomedical (Polylactide)-(Polyethylene Glycol) Mixture as Drug Carrier

2014 ◽  
Vol 1002 ◽  
pp. 99-104
Author(s):  
Hong Jiang ◽  
Li Bo Wang ◽  
De Jun Xu ◽  
Xiao Yang Liu
Keyword(s):  
Polyethylene Glycol ◽  
Drug Carrier ◽  
Amorphous State ◽  
Solvent Casting ◽  
X Ray Diffraction ◽  
X Ray ◽  
Weight Percentage ◽  
Melt Compounding ◽  
Heating And Cooling ◽  
Degradation Time

For the purpose of drug carrier and delivery, the polylactide was modified by polyethylene glycol blending with the weight percentage of 80/20 by two methods: solvent-casting and melt-compounding. Characterizations of X-ray diffraction, Scanning Electron Microscope and degradation experiments have been done to study the crystallization, miscibility and degradation behavior. The melt-compounding provides a better miscibility associated with longer degradation time, however the heating procedure effects the polymers. Because of the heating and cooling cycle, the polymers had an opportunity to crystalize and the crystal peak can be seen in the XRD results. While the solvent-casting avoids the high temperature experience of blend with an amorphous state, and provides lower miscibility and short degradation time. These significant features will be considerable factors in drug carrier design.

Austenite-Ferrite Transformation in Non-Oriented Electrical Steels

2007 ◽  
Vol 560 ◽  
pp. 85-89
Author(s):  
Enrique Díaz Barriga-Castro ◽  
Armando Salinas-Rodríguez ◽  
Enrique Nava-Vázquez
Keyword(s):  
Electrical Steel ◽  
Tensile Ductility ◽  
X Ray Diffraction ◽  
Electrical Steels ◽  
Transformation Temperatures ◽  
X Ray ◽  
Heating And Cooling ◽  
Ferrite Transformation ◽  
Isothermal Heat Treatments

The aim of the present work is to determine the austenite to ferrite transformation temperatures in a Si-Al non-oriented electrical steel. Critical transformation temperatures on heating and cooling are determined using an in-situ X-ray diffraction technique where the specimen is heated or cooled in a stepwise manner. The transformation temperatures are estimated from changes in the intensities of the (110)α and (111)γ peaks as a function of temperature. The time evolution of the microstructure resulting from isothermal heat treatments at temperatures between 800 and 1000 °C applied after cooling from 1050 °C is followed by quantitative metallography on samples quenched into water. The results show that, on cooling, formation of ferrite starts at about 950 °C and ends at 790 °C, indicating a strong effect of Si and Al on the austenite to ferrite and eutectoid transformations. These results suggest that the low tensile ductility exhibited by this material at temperatures near 1000 °C can be attributed to strain localization in strain-induced ferrite formed at temperatures as high as 1025 °C.

Anomalous solid state reaction between SiC and Pt

1990 ◽  
Vol 5 (3) ◽  
pp. 601-608 ◽  
Author(s):  
T.C. Chou
Keyword(s):  
Solid State ◽  
Diffusion Zone ◽  
Solid State Reaction ◽  
Periodic Structures ◽  
Amorphous State ◽  
Laser Raman Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Laser Raman ◽  
Auger Microscopy

Periodic structures are generated by solid state reaction between platinum (Pt) and silicon carbide (SiC). At temperatures above 900°C, periodic structures consisting of alternating layers of platinum silicides and carbon are produced in the diffusion zone. The composition profile across the diffusion zone and the chemistry of the periodic structures are investigated by scanning electron microscopy (SEM), scanning Auger microscopy (SAM), x-ray diffraction (XRD), and laser Raman microprobe. The formation of the platinum silicides causes an interfacial melting between Pt and SiC. X-ray diffraction indicates that Pt3Si is formed at 900°C, while Pt2Si is formed at 1000 °C. Laser Raman spectroscopy indicates that carbon is in either an amorphous state or a highly ordered graphitic state, depending upon its location from the reaction interface. The mechanism of formation of the periodic structure is discussed in terms of the solubility of carbon in platinum silicide during the solidification process.

Structural and Morphologies of (1-x)BaTiO3-xBaFe0.5Nb0.5O3 Solid Solution

2008 ◽  
Vol 55-57 ◽  
pp. 137-140 ◽  
Author(s):  
Sukum Eitssayeam
Keyword(s):  
Solid Solution ◽  
Structural Change ◽  
Solid State ◽  
Room Temperature ◽  
Xrd Analysis ◽  
Dielectric Measurement ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Temperature Changes ◽  
X Ray

The structural and physical properties of(1−x)BaTiO3 –xBaFe0.5Nb0.5O3 ceramics system were investigated as a function of the BaFe0.5Nb0.5O3 content by X-ray diffraction (XRD) and dielectric measurement technique. Studies were performed on the samples prepared by solid state reaction for x = 0, 0.2, 0.4 and 0.6. The XRD analysis demonstrated that with increasing BFN content in (1−x)BT–xBFN, the structural change occurred from the tetragonal to the cubic phase at room temperature. Changes in the morphology were then related to these structural depending on the BFN content.

A Thermodynamic Model for Solid State Amorphization: Application to Ni-Ti Multilayers of Different Microstructures

1997 ◽  
Vol 472 ◽  
Author(s):  
A. Böttger ◽  
R. Benedictas ◽  
E.J. Mittemeijer
Keyword(s):  
Solid State ◽  
Grain Boundaries ◽  
Thermodynamic Model ◽  
Driving Force ◽  
Crucial Importance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Formation Energies ◽  
State Amorphization

ABSTRACTOn the basis of an assessment of both the phase-formation energies and the energies of interfaces and grain boundaries the driving force for solid state amorphization (SSA) in crystalline Ni- crystalline Ti and amorphous Ni- crystalline Ti multilayers was calculated. It followed that the structure of the interfaces and grain boundaries, and thus their energies is of crucial importance for the occurrence (or not) of SSA. The SSA behaviour of the two types of Ni-Ti multilayers upon annealing was investigated using X-ray diffraction and (high resolution) transmission electron microscopy. The crystalline Ni- crystalline Ti multilayers showed SSA at both the Ni-Ti interfaces and the Ti grain boundaries. The amorphous Ni- crystalline Ti multilayers exhibited SSA at the Ti grain boundaries only. These observations agree with the predictions from the thermodynamic model.

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