Ultrasonic relaxation in Zinc–Borate glasses

Borate glasses in the system (1 −  x) [29Na 2O − 4Al 2O 3 − 67B 2O 3] −  x ZnO with ( x = 0, 5, 10, 15, 20, 25, 30, and 35 mol%), have been prepared by the melt quenching technique. The longitudinal ultrasonic attenuation of the prepared sample has been measured using the pulse echo technique at ult...

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Bibliographic Details
Published in:Current applied physics 2012, 12(2), , pp.589-596
Main Authors: El-Falaky, G.E., Gaafar, M.S., El-Aal, N.S. Abd
Format: Article
Language:English
Subjects:
Activation energy
Borate glasses
Concentration (composition)
Dispersions
Glass
Internal friction
melting
Melts
Quenching
temperature
Ultrasonic attenuation
Ultrasonic relaxation
Zinc oxide
Zinc-borate glasses
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Summary:Borate glasses in the system (1 −  x) [29Na 2O − 4Al 2O 3 − 67B 2O 3] −  x ZnO with ( x = 0, 5, 10, 15, 20, 25, 30, and 35 mol%), have been prepared by the melt quenching technique. The longitudinal ultrasonic attenuation of the prepared sample has been measured using the pulse echo technique at ultrasonic frequencies 2, 4, 6 and 8 MHz in the temperature range between 160 and 300 K. The results showed well-defined peak whose position shifts toward higher temperature with increasing frequency. The mean activation energy is strongly composition sensitive. The position and overall shape of the loss peaks in dependence on composition were analyzed in terms of an assumed loss of standard linear solid type with low dispersion, and a broad distribution of Arrhenius-type relaxation with temperature independent relaxation strength. The dependence of ultrasonic attenuation on temperature has been interpreted in terms of a thermally activated relaxation process which arises when ultrasonic waves disturb the equilibrium of an atom moving in a double-well potential in the glass network. The dependence of activation energy on composition suggests that the structure of these glasses changes at 15 mol% ZnO concentration. ► Prepared alkali- borate glasses (1 −  x) [29Na 2O − 4Al 2O 3 − 67B 2O 3] −  x ZnO. ► Attenuation studied showed well-defined peak shifts toward high temperature and frequency. ► Attributed to thermally activated relaxation governed by the Arrhenius relationship. ► The number of loss centers dependence of the elastic moduli and oxygen density. ► Activation energy and attempt frequency increase with increase the ZnO.
ISSN:1567-1739
1878-1675
DOI:10.1016/j.cap.2011.09.009