Activation Energy Spectra for Relaxation in Amorphous Materials. I. Volume Relaxation in Polystyrene and Polyvinyl Acetate

1969 ◽  
Vol 40 (11) ◽  
pp. 4254-4260 ◽  
Author(s):  
R. M. Kimmel ◽  
D. R. Uhlmann
Keyword(s):  
Activation Energy ◽  
Amorphous Materials ◽  
Polyvinyl Acetate ◽  
Energy Spectra ◽  
Volume Relaxation

Activation energy spectra and relaxation in amorphous materials

1983 ◽  
Vol 18 (1) ◽  
pp. 278-288 ◽  
Author(s):  
M. R. J. Gibbs ◽  
J. E. Evetts ◽  
J. A. Leake
Keyword(s):  
Activation Energy ◽  
Amorphous Materials ◽  
Energy Spectra

Structural Relaxation Process in CuHfTi Amorphous Alloys

2009 ◽  
Vol 283-286 ◽  
pp. 533-538 ◽  
Author(s):  
Kazumasa Yamada ◽  
N. Shinagawa ◽  
M. Sogame ◽  
I.A. Figueroa ◽  
Hywel A. Davies ◽  
...  
Keyword(s):  
Activation Energy ◽  
Relaxation Process ◽  
Structural Relaxation ◽  
Amorphous Alloys ◽  
Melt Spinning ◽  
Amorphous Materials ◽  
Ternary Alloys ◽  
Relaxation Processes ◽  
Scanning Calorimetry ◽  
Structure Relaxation

The aim of this research is to clarify a quantitative evaluation in the structural relaxation processes focusing on the activation energy in Cu based amorphous alloys. The activation energy for structural relaxation process in a metal type amorphous CuHfTi ternary alloys, with cross sections of typically 0.03 mm x 2.0 mm, prepared by chill-block melt spinning has been investigated by Differential Scanning Calorimetry (DSC) with a cyclically heating technique. Activation energies for structural relaxation with a spatial quantity in amorphous materials have been discussed by use of a relaxed ratio function that depends on annealing temperature and time. In the present work, the distributions for the Activation Energy Spectrum (AES) were observed almost 152 kJmol-1 (1.58 eV). Another result has been also established that the “reversible” AES model energy distribution though the cyclically structure relaxation occurs even in amorphous Cu60Hf20Ti20 alloy.

scholarly journals Kinetic Processes in Amorphous Materials Revealed by Thermal Analysis: Application to Glassy Selenium

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2725 ◽  
Author(s):  
Málek ◽  
Svoboda
Keyword(s):  
Activation Energy ◽  
Crystal Growth ◽  
Viscous Flow ◽  
Structural Relaxation ◽  
Amorphous Materials ◽  
Supercooled Liquid ◽  
Thermomechanical Analysis ◽  
Growth Data ◽  
Scanning Calorimetry ◽  
Kinetic Processes

It is expected that viscous flow is affecting the kinetic processes in a supercooled liquid, such as the structural relaxation and the crystallization kinetics. These processes significantly influence the behavior of glass being prepared by quenching. In this paper, the activation energy of viscous flow is discussed with respect to the activation energy of crystal growth and the structural relaxation of glassy selenium. Differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and hot-stage infrared microscopy were used. It is shown that the activation energy of structural relaxation corresponds to that of the viscous flow at the lowest value of the glass transition temperature obtained within the commonly achievable time scale. The temperature-dependent activation energy of crystal growth, data obtained by isothermal and non-isothermal DSC and TMA experiments, as well as direct microscopic measurements, follows nearly the same dependence as the activation energy of viscous flow, taking into account viscosity and crystal growth rate decoupling due to the departure from Stokes–Einstein behavior.

Amorphous ceramics as the particulate phase in electrorheological materials systems

1996 ◽  
Vol 11 (1) ◽  
pp. 144-155 ◽  
Author(s):  
Daniel R. Gamota ◽  
Adam W. Schubring ◽  
Brian L. Mueller ◽  
Frank E. Filisko
Keyword(s):  
Activation Energy ◽  
Alkali Metals ◽  
Amorphous Materials ◽  
Stimulus Frequency ◽  
Metal Species ◽  
Particulate Phase ◽  
Ceramic Powders ◽  
Sodium Aluminosilicate ◽  
Paraffin Oil ◽  
Frequency Temperature

Several electrorheological (ER) materials systems composed of amorphous ceramic powders dispersed in light paraffin oil were developed to determine if relationships among ER activities, dielectric properties, compositions, porosities, and oxide species could be identified. The results of the studies suggested that trends among ER activity, dielectric phenomena, and alkali metal species existed. The aluminosilicate powders developed with various alkali metals showed that the ER activity increased as the activation energy decreased. The sodium aluminosilicate appeared to have the greatest ER activity and the lowest activation energy, while the cesium aluminosilicate displayed the weakest ER response, but had the highest activation energy. The thermodielectric responses of the different oxide materials systems developed with sodium showed that the mechanisms contributing to the dielectric dispersions had similar activation energies; however, the magnitudes of the recorded ER activities varied, and thus a direct correlation was not apparent. In addition, studies conducted with ER materials composed of sodium aluminosilicate powders of varying porosities showed that ER activities increased with increasing porosity. Furthermore, the analysis of the results of the thermodielectric and rheological studies of the different amorphous materials ER systems suggested that these materials may have an optimal stimulus frequency/temperature for ER activity.

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