Kinetics of failure in a composite glass-crystal system

1986 ◽  
Vol 18 (3) ◽  
pp. 404-407
Author(s):  
V. N. Dubovik ◽  
A. M. Raikhel' ◽  
L. G. Ivchenko ◽  
O. A. Nepomnyashchii
Keyword(s):  
Crystal System ◽  
Composite Glass ◽  
Glass Crystal ◽  
Kinetics Of

Diffusion Enhancement in Glassy Metals Under Non-Equilibrium Conditions

1995 ◽  
Vol 400 ◽  
Author(s):  
S. Bellini ◽  
G. Mazzone ◽  
A. Montone ◽  
M. Vittori-antisari Enea ◽  
C.R. Casaccia
Keyword(s):  
Free Volume ◽  
Growth Kinetics ◽  
Bulk Diffusion ◽  
High Energy ◽  
First Case ◽  
Diffusion Enhancement ◽  
Glass Crystal ◽  
Kinetics Of ◽  
Crystal Interface ◽  
Diffusion Properties

AbstractThe diffusion properties of a Ni-Zr metallic glass formed at the interface of a bulk diffusion couple have been studied in conditions far from a fully relaxed state. The growth kinetics of the interface film have been enhanced by both plastic deformation and high energy electron irradiation. Different results have been obtained in the two cases, since in the first case the film grows exponentially with time, while in the second case the usual square root dependence on time is observed. This behaviour has been interpreted as a consequence of the annihilation kinetics of the excess free volume introduced in the glass by the above methods. Two different mechanisms of free volume annihilation , namely exchange with a crystal vacancy at the glass-crystal interface and structural relaxation in the bulk glassy phase have been considered to be operative so that the nature of the growth kinetics has been found to depend on the mechanism predominant in each experimental condition.

Effects of Dispersed Al2O3 Particles on Sintering of LTCC

2008 ◽  
Vol 39-40 ◽  
pp. 375-380
Author(s):  
Ralf Müller ◽  
Stefan Reinsch ◽  
Markus Eberstein ◽  
Joachim Deubener ◽  
A. Thiel ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Al2o3 Particle ◽  
Model Composite ◽  
Heating Microscopy ◽  
Glass Crystal ◽  
Rate Controlled ◽  
Higher Temperature ◽  
Crystal Particle ◽  
Kinetics Of ◽  
Glass Viscosity

The sintering of Low Temperature Co-fired Ceramics prepared from alumoborosilicate glass- and Al2O3 powders of similar small particle size was studied by dilatometry, heating microscopy, microstructure analysis, glass- and effective viscosity measurements. The steric effect of Al3O3 inclusions was studied using a “non-reactive” model composite. With increasing Al3O3 volume fraction ( Φ ≤ 0.45), sintering decelerates and its final stage shifts to higher temperature. The attainable shrinkage is reduced as Al2O3 particle clusters bearing residual pores become more frequent. The kinetics of sintering could be described formally superposing the weighed contributions of differentially sized and randomly composed glass-crystal particle clusters and assuming a sintering rate controlled by the effective matrix viscosity, which increases with Φ and with progressive wetting of Al2O3 particles during densification. The “reactive” model composite shows significant dissolution of Al2O3 into the glass, which has two opposed effects on sintering: reducing Φ and increasing glass viscosity. For the present case ( Φ = 0.25), the latter effect dominates and sintering is retarded by Al2O3 dissolution. Crystallization of wollastonite starts after full densification. Dissolution of Al2O3 was found to promote the subsequent growth of anorthite.

scholarly journals TECHNOLOGY FOR PRODUCING COMPOSITE GLASS-CRYSTAL FACING MATERIALS BASED ON MIXED CULLET

2020 ◽  
pp. 106-114
Author(s):  
N. Bondarenko ◽  
O. Puchka ◽  
V. Bessmertnyy ◽  
S. Chuev ◽  
I. Izotova ◽  
...  
Keyword(s):  
Sodium Silicate ◽  
Silicate Glass ◽  
Liquid Glass ◽  
Fluorescence Analysis ◽  
Liquid Sodium ◽  
Sodium Silicate Glass ◽  
Furnace Sintering ◽  
Composite Glass ◽  
Glass Crystal ◽  
Diamond Saw

An effective energy-saving technology for producing composite glass-crystal facing materials based on fractionated cullet of sheet and container glasses, cullet of porcelain and sodium liquid glass has been developed. The use of fine porcelain powder in the composition of composite glass-crystal facing materials in an amount of up to 10 wt is justified. % and liquid sodium glass up to 5 wt. %. It is shown that the optimal fractional composition of granulated mixed cullet is 35 wt. % fraction 0.63-0.80 mm; 35 wt. % - fractions of 0.80-1.25 mm and 30 wt. % fraction of 1.25-3.15 mm. Polytherms of viscosity of colorless, green and brown container glasses, as well as sheet glass, are calculated. The possibility of using mixed cullet for obtaining composite glass-crystal facing materials is on the basis of obtained dependencies. The chemical composition of sheet and container glasses and porcelain is studied using x-ray fluorescence analysis. Optimal charge compositions have been developed to obtain glass-crystal materials with compressive strength up to 79 MPa. The technology of obtaining composite glass-ceramic facing material includes the following technological operations: milling of glass breakage; grinding cullet of porcelain; drying of sodium liquid glass; the screening of crushed cullet on fractions; the grind of crushed cullet of China; grinding the dried sodium silicate glass; weighing the components in accordance with the developed formulations, the averaging of the graded cullet with fine porcelain; averaging the mixture of finely ground dried sodium silicate glass; stacking the mixture in a metal mold; compaction of the mixture in metal molds; heat treatment in a muffle furnace (sintering); extraction of facing tiles from molds; trimming the edges of the tiles with a diamond saw; quality control of finished products.

scholarly journals Tuning the spontaneous formation kinetics of caffeine : malonic acid co-crystals

CrystEngComm ◽  
2016 ◽  
Vol 18 (15) ◽  
pp. 2617-2620 ◽  
Author(s):  
K. P. Nartowski ◽  
Y. Z. Khimyak ◽  
D. J. Berry
Keyword(s):  
Malonic Acid ◽  
Crystal System ◽  
Spontaneous Formation ◽  
Formation Kinetics ◽  
And Control ◽  
Kinetics Of

It has previously been reported that the caffeine : malonic acid co-crystal system forms spontaneously upon the contact of the two materials, here we explore the mechanism of this formation and control the kinetics to enable us to monitor the conversion.

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.

Isothermal Crystallization Kinetics in Simulated High-Level Nuclear Waste Glass

1996 ◽  
Vol 465 ◽  
Author(s):  
John D. Vienna ◽  
Pavel Hrma ◽  
Donald E. Smith
Keyword(s):  
Crystallization Kinetics ◽  
High Level Waste ◽  
Transformation Kinetic ◽  
Isothermal Crystallization Kinetics ◽  
Isothermal Method ◽  
Glass Crystal ◽  
Temperature Transformation ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Kinetics Of

ABSTRACTCrystallization kinetics of a simulated high-level waste (HLW) glass were measured and modelled. Kinetics of acmite growth in the standard HW39–4 glass were measured using the isothermal method. A time-temperature-transformation (TTT) diagram was generated from these data. Classical glass-crystal transformation kinetic models were empirically applied to the crystallization data. These models adequately describe the kinetics of crystallization in complex HLW glasses (i.e., RSquared = 0.908). An approach to measurement, fitting, and use of TTT diagrams for prediction of crystallinity in a HLW glass canister is proposed.

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

Sign in / Sign up

Export Citation Format

Share Document