Diffusion and solubility of hydrogen and water in vitreous silica

  • 201 Pages
  • 3.55 MB
  • English
Statementby Nicholas John Pitt.
The Physical Object
Pagination201leaves,[3] leaves of plates
ID Numbers
Open LibraryOL13949745M

Deuterium permeation, diffusion, and solubility measurements have been made for several types of vitreous silica at temperatures ranging from 0 to °C.

The activation energies for permeation and diffusion were found to be somewhat temperature dependent. Isotope exchange between structural hydroxyl and the diffusing deuterium was found to occur at temperatures.

° by:   ELSEVIER Journal of Non-Crystalline Solids (~,) ~,URNAL OF Diffusion of water in vitreous silica " P.B. McGinnis *, J.E. Shelby Glass Science Laboratory, NYS College of Ceramics, Alfred University, Alfred, NYUSA Abstract Hydroxyl has been removed from three different commercial vitreous silicas at temperatures between and ° by:   1.

Introduction. Numerous research studies, have been conducted on hydrogen permeation and diffusion in various types of vitreous silica. The initial study by Hetherington and Jack indicated that the hydrogen diffusion coefficient in a silica glass (type I) made by fusion of quartz crystals was dependent on the hydrogen concentration at high by: The solubility of gases in vitreous silica complies well with Henry's Law at low pressures.

Deviations observed at high pressures have been explained by site saturation, i.e., the number of dissolved molecules approaches the number of available sites that are Cited by: 2. hydrogen is introduced into the glass during melting.

Some processes are known which directly use the high solubility of hydrogen (and He) in vitreous silica. During melting the hydrogen and helium dissolve in the glass and a bubble free vitreous silica is obtained. For the above reasons it is important to know about the behaviour of hydro­Cited by: 3.

The initial non-Fickean behavior is most likely due to an increase in the water solubility of the silica glass with time. Davis and Tomozawa have shown that at °C the water solubility increases with heat-treatment time.

Download: Download full-size image; Fig. (a) Water uptake for silica glass samples heat-treated at °C under   Theory. It was not until recently that a quantitative accounting of the permeability through silica membranes was given.This employed an equation originally derived to describe the permeability of monatomic gases in vitreous glass and was based on a mechanism involving jumps between solubility equation was derived using a classical statistical mechanics approach.

The solubility of hydrogen in amorphous silica at a temperature of °C and pressures up to 75 kbar is studied using a quenching technique.

Details Diffusion and solubility of hydrogen and water in vitreous silica EPUB

The molar ratio H2/SiO2 is found to linearly increase. The Solubility of Gases in Silica and Diffusion Con. Permeation Velocities at High Pressures. The Behaviour of Hydrogen Isotopes in Diffusion.

The Influence of Phase Changes upon Permeability. The Permeability Constants to Water of Various. A Modified Diffusion Law for Sorption of Water. /5(1). hydrogen, oxygen or water) are present even in so-called extremely pure silica since its production, can be produced during the irradiation, or can be absorbed from the atmosphere during thermal treatments.

Moreover, some of these molecules, as for ex-ample hydrogen or uorine, are ad hoc introduced in the material to improve speci c. Hydrogen diffusion in a silica glass at high temperature (– °C) was investigated. The starting material was a silica glass that was melted in hydrogen atmosphere and contained a high.

The temperature dependence of oxygen diffusion in vitreous silica was determined over the range –°C using a completely new method. Hydrogen reaction with dissolved molecular oxygen.

Arun K. Varshneya, John C. Mauro, in Fundamentals of Inorganic Glasses (Third Edition), Vitreous silica. Vitreous silica is the most refractory glass in commercial usage. In addition to its ability to withstand exceptionally high temperatures, it has a high resistance to chemical corrosion (particularly to acids), a very low electrical conductivity, a very low (~ × 10 − 7 /°C.

Molecular diffusion and solubility of hydrogen isotopes in vitreous silica Journal of Applied Phys (); / Diffusion of Hydrogen and Deuterium in Fused Quartz. This article is cited by 29 publications. Sin Sheng T'sai, T. Hogness. The Diffusion of Gases through Fused Quartz. K.M.

Davis, M. Tomozawa, Water diffusion into silica glass: Structural changes in silica glass and their effect on water solubility and diffusivity, Journal of Non-Crystalline Solids, /(95),3, (), (). The diffusivity of the oxygen ion in vitreous silica has been directly determined by exchange measurements employing the stable isotope 18O and mass spectrometer analysis.

It. The diffusion coefficient and solubility of water in silica glass optical fiber cladding were measured in the temperature range of degreesC and were compared with the corresponding values. We report diffusion experiments where hydrogen permeates through a 1 mm wall of vitreous silica at ° C with applied gas pressures of 70, and each pressure, and at steady state, the flux and the amount of hydrogen in the material are measured.

Within the experimental accuracy we find that the flux is proportional to the pressure and that the hydrogen. study the possible effects of different cooling rates on hydrogen solubility in vitreous silica.

Such quench effects were indeed observed for the water speciation in hydrous silicate glasses [26], in which the ratio of structurally bonded OH groups and molecular water. The diffusivity of the oxygen ion in vitreous silica has been directly determined by exchange measurements employing the stable isotope 18 O and mass spectrometer analysis.

It was found that over the temperature range ° to °C the results can be represented by the equation D = × 10 −2 exp (‐71,/RT) cm 2 sec − results are compared with other measurements of oxygen.

The diffusion of Cs +, Rb +, and K + ions was measured in three grades of vitreous SiO 2 by the radiotracer‐sectioning technique or Rutherford, backscattering spectroscopy. The values of the diffusion coefficient, D, at °C decrease strongly with increasing ionic radius, changing by about two and one‐half orders of magnitude per row of the periodic table.

Abstract. The structures formed by hydrogen in two types of silica glass are investigated using infrared spectroscopy, 1 H magic angle spinning magnetic resonance spectroscopy, and quadrupole mass spectrometry.

The results obtained from these investigations show that hydrogen in silica glass can exist in the form of isolated SiOH groups, SiOH groups with hydrogen bonds, pairs of neighboring.

Lastly, solid-state diffusion can add to the permeance of gases in glass networks due to the existence of solubility sites in the silica. The behavior of the gas molecules is similar to that of surface diffusion, except that, instead of small pores, solubility sites are assumed to exist in the solid-state diffusion model [ 40, 41, 42 ].

Water adsorbs through hydrogen bonds formed between water and surface hydroxyl groups on the molecules,10,11 and with vitreous silica To our knowledge, except for the work by de Leeuw on water interactions with a-quartz surfaces,13 few theoretical studies of the interaction.

Attempts to introduce molecular water into dry, natural quartz crystals by diffusive transport and thus weaken them hydrolytically at T = °–°C and PH 2 O = – MPa have failed.

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Infrared spectroscopy of hydrothermally annealed single crystals of natural quartz reveals the diffusive uptake of interstitial hydrogen (resulting in hydroxyl groups) at rates similar to those. This could lead to some systematic underestimation of hydrogen solubility. Only for reference, Table 1 also contains hydrogen contents calculated using the linear calibration coefficient for H 2 in SiO 2 glass (Shelby, Shelby, J.E.

() Protonic species in vitreous silica. Journal of Non-crystalline Solids). This would. Dissolution of Hydrogen in Fused Silica S. FAILE and D. ROY amount of hydrogen dissolved in fused SOz glass as Hz molecules as opposed to the reacted form, which can increase the OH concentration in the glass, was investigated.

Information on the amountâ -â and form of the hydrogen in glass is of use in studies of the mechanism of radiation coloration resistance in hydrogen. The silica gel gave the same colorimetric silica as the vitreous silica. The solubility of amorphous silica at the vapor pressure of the solution, from 0 to /sup 0/C, is given by the equation log C = /T +where C is the silica concentration in mg/kg and T is absolute temperature.

The solubility of silica gel in distilled water and dilute and alkaline solutions has been investigated.

Description Diffusion and solubility of hydrogen and water in vitreous silica EPUB

The solubility has been studied as a function of the pH of the gel preparation, pH s, and of the pH of the dissolution media, pH L.A kinetic model for the dissolution process has been developed that permits the determination of the rate constant as well as the equilibrium value of the.

We have recorded quantitative optical absorption and Raman spectra of H2 and D2 diffused into silica optical fibers at a pressure of atm. The absorption spectra recorded were fundamental through the third overtone for H2 ( through μm) and the first through fourth overtone for D2 ( through μm). 6 shows that the nucleation rate also depends on the energy barrier to creating a nucleus (pit) with radius, r c such that For vitreous silica at °C in C/C e = (highly undersaturated), r c ranges from ≈ to 4 Å by using accepted interfacial free-energy values of 37–62 mJ/m 2, respectively (calculated from this study assuming a.The diffusion properties of a number of multicomponent silicate glasses were studied via the kinetic thermal desorption mass spectrometry.

The diffusion coefficients of water and carbon dioxide molecules were determined for the first time in the glasses at temperatures ranging between and °C. The diffusion coefficients of water and carbon dioxide decrease with the reduction of the.