Influence of Preliminary Nucleation on the Physicogeometric Kinetics of Glass Crystallization

2012 ◽  
pp. 209-223 ◽  
Author(s):  
Nobuyoshi Koga ◽  
Jaroslav Šesták
Keyword(s):  
Glass Crystallization ◽  
Kinetics Of

Onset Temperatures and Kinetics of Quartz Glass Crystallization

2018 ◽  
Vol 63 (2) ◽  
pp. 290-294 ◽  
Author(s):  
A. I. Nepomnyashchikh ◽  
A. A. Shalaev ◽  
T. Yu. Sizova ◽  
A. S. Paklin ◽  
A. N. Sapozhnikov ◽  
...  
Keyword(s):  
Quartz Glass ◽  
Glass Crystallization ◽  
Kinetics Of

scholarly journals Crystallization of GeO2–Al2O3–Bi2O3 Glass

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 522
Author(s):  
Małgorzata Płońska ◽  
Julian Plewa
Keyword(s):  
Activation Energy ◽  
Glass Matrix ◽  
Kissinger Method ◽  
Oxide Glass ◽  
Germanium Oxide ◽  
Glass Crystallization ◽  
Glassy Sample ◽  
Controlled Crystallization ◽  
Two Phases ◽  
Kinetics Of

In the presented work, two kinds of germanium oxide glass with different compositions, namely GeO2 and GeO2–Al2O3–Bi2O3, were investigated. After controlled crystallization of a glassy sample, the emission in the NIR-range was determined (1165 nm with excitation at 470 nm). To better understanding the kinetics of the glass crystallization, the activation energy was also determined by applying the Kissinger method. The obtained results show that in the case of GeO2–Al2O3–Bi2O3, activation energy value was 400 and 477 kJ/mol, which means that such values are significantly larger than for pure GeO2 (254 kJ/mol). The investigations also show that two phases crystallized in the complex glass matrix: the mullite-like phase and germanium oxide.

scholarly journals Non-isothermal crystallization of lithium germanophosphate glass studied by different kinetic methods

2018 ◽  
Vol 50 (2) ◽  
pp. 193-203 ◽  
Author(s):  
Srdjan Matijasevic ◽  
Snezana Grujic ◽  
Vladimir Topalovic ◽  
Jelena Nikolic ◽  
Sonja Smiljanic ◽  
...  
Keyword(s):  
Isothermal Condition ◽  
Nucleation And Growth ◽  
Glass Crystallization ◽  
Crystallization Peak ◽  
Crystal Transformation ◽  
Model Free ◽  
Complex Process ◽  
Glass Crystal ◽  
Linear Integral ◽  
Kinetics Of

Crystallization kinetics of 22.5Li2O?10Al2O3?30GeO2?37.5P2O5 (mol%) glass was studied under non-isothermal condition using the differential thermal analysis (DTA). The study was performed by using the first crystallization peak temperature (Tp1) which belongs to the precipitation of LiGe2(PO4)3 phase in the glass. The activation energy of glass crystallization (Ea) was determined using different isokinetic methods. The dependence of Ea on the degree of glass-crystal transformation (?) was studied using model-free isoconversional linear integral KAS (Kissinger-Akahira-Sunose) and FWO (Flynn-Wall-Ozawa) methods. It was shown that the Ea varies with ? and hence with temperature and consequently the glass/crystal transformation can be described as a complex process involving different mechanisms of nucleation and growth.

Laser-Induced Glass-Crystallization Kinetics of GeSe2 Investigated by Light Scattering

1985 ◽  
Vol 452 (1) ◽  
pp. 275-295 ◽  
Author(s):  
M. BALKANSKI ◽  
E. HARO ◽  
Z. S. XU ◽  
J-F. MORHANGE ◽  
G. P. ESPINOSA ◽  
...  
Keyword(s):  
Light Scattering ◽  
Crystallization Kinetics ◽  
Glass Crystallization ◽  
Kinetics Of

Direct observations of radiation-enhanced transformations in glass

1983 ◽  
Vol 41 ◽  
pp. 354-355
Author(s):  
J. F. DeNatale ◽  
D. G. Howitt
Keyword(s):  
Glass Matrix ◽  
Diffusion Mechanism ◽  
Bubble Formation ◽  
Silicate Glasses ◽  
Phase Decomposition ◽  
Direct Observations ◽  
Thin Foils ◽  
Oxygen Bubble ◽  
Electron Energy Loss ◽  
Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

Ion Beam Induced Interfacial Reactions in Molybdenum Thin Films on Silicon

1981 ◽  
Vol 39 ◽  
pp. 162-163
Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Ion Beam ◽  
Chemical Vapor ◽  
Interfacial Reactions ◽  
Practical Applications ◽  
Microelectronic Devices ◽  
Recent Emergence ◽  
Chemical Vapor Deposited ◽  
Atomic Mixing ◽  
Silicon Interface ◽  
Kinetics Of

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.

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