Related Experiment Video
Updated: Aug 15, 2026
06:48
Fluid-cell Raman Spectroscopy for operando Studies of Reaction and Transport Phenomena during Silicate Glass Corrosion
Published on: May 9, 2025
Internal friction and vulnerability of mixed alkali glasses
Robby Peibst1, Stephan Schott, Philipp Maass
1Institut für Physik, Technische Universität Ilmenau, 98684 Ilmenau, Germany.
Physical Review Letters
|October 4, 2005
Summary
The mixed alkali effect in glasses is explained by a hopping model where few vacancies drive ion-ion interactions. This model reproduces the observed changes in internal friction and ion mobility, crucial for understanding glass properties.
Area of Science:
- Materials Science
- Solid State Physics
- Glass Science
Background:
- The mixed alkali effect describes unusual properties in glasses containing two types of mobile ions.
- Understanding ion transport and mechanical relaxations in glasses is crucial for their application.
Purpose of the Study:
- To explain the mixed alkali effect in glasses using a hopping model.
- To understand the origins of internal friction peaks and ion mobility changes in mixed alkali systems.
Main Methods:
- Development of a hopping model for mobile ions in glasses.
- Inclusion of ion-vacancy and ion-ion interactions within the model.
- Analysis of the effect of vacancy concentration on ion transport and friction.
Main Results:
- The model successfully reproduces the mixed alkali effect, including internal friction peaks and the vulnerability of majority ion mobility.
- A small fraction of vacancies (c(V)) is shown to be key to explaining the observed phenomena.
- Ion-vacancy and ion-ion exchange processes are identified as the cause of internal friction peaks.
Conclusions:
- The hopping model provides a unified explanation for the mixed alkali effect in glasses.
- Minority ions can trap vacancies, leading to significant changes in ion mobility.
- The model's parameters can be adjusted to match experimental observations in various glass systems.
Related Concept Videos
01:26Alkali Aggregate Reaction in Concrete
The alkali-aggregate reaction in concrete involves natural siliceous minerals in aggregates reacting with alkaline hydroxides derived from cement alkalis. This reaction forms an alkali-silica gel that absorbs water, swells, and increases in volume, which is confined by the surrounding cement paste, creating internal pressures that crack and disrupt the concrete. The extent of expansion and damage can be partly attributed to the alkali-silica reaction's osmotic hydraulic pressure and the...
01:24Stress-Strain Diagram - Brittle Materials
Brittle materials, including glass, cast iron, and stone, exhibit unique characteristics. They fracture without considerable change in their elongation rate, indicating that their breaking and ultimate strength are equivalent. Such materials also show lower strain levels at the point of rupture. The failure in brittle materials predominantly results from normal stresses, as evidenced by the rupture created along a surface perpendicular to the applied load. These materials do not display...
01:26Unsoundness of Aggregate due to Volume Change
Unsoundness in aggregates due to volume changes is primarily caused by the physical alterations aggregates undergo, such as freezing and thawing, thermal changes, and wetting and drying. Unsound aggregates, when subjected to these changes, result in volume change upon disintegration. This, in turn, contributes to the deterioration of concrete, including scaling, pop-outs, and cracking. Particular types of aggregates, such as porous flints, cherts, and those containing clay minerals, are...
04:02Weak Acid Solutions
Few compounds act as strong acids. A far greater number of compounds behave as weak acids and only partially react with water, leaving a large majority of dissolved molecules in their original form and generating a relatively small amount of hydronium ions. Weak acids are commonly encountered in nature, being the substances partly responsible for the tangy taste of citrus fruits, the stinging sensation of insect bites, and the unpleasant smells associated with body odor. A familiar example of a...
02:34Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility
Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, and solubilities (miscibilities) of substances. Molar mass, molecular shape, and polarity affect the strength of different intermolecular forces, which influence the magnitude of physical properties across a family of molecules.
Temporary attractive forces like dispersion are present in all molecules, whether they are polar or nonpolar. They...
Temporary attractive forces like dispersion are present in all molecules, whether they are polar or nonpolar. They...