Low temperature ultrasonic study of BNaOBiNb glasses

A series of (x/2) Bi2O3–(x/2) Nb2O5–(100 – x) Na2B4O7, 5 ≤ x ≤ 30 mol% glasses were synthesized in bulk form and their ultrasonic absorption (α) curves were explored at different ultrasonic frequencies (f), 2≤ f ≤ 10 MHz, and at multiple temperatures (T) ranging from 140 to 300 K. Several features o...

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Bibliographic Details
Published in:Ceramics international 2020-10, Vol.46 (15), p.24544-24551
Main Authors: Mahmoud, I.S., Saddeek, Yasser B., Saddek, Amr Bakr
Format: Article
Language:English
Subjects:
Glass
Mechanical properties
Transition metal oxides
Ultrasonic relaxation
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Summary:A series of (x/2) Bi2O3–(x/2) Nb2O5–(100 – x) Na2B4O7, 5 ≤ x ≤ 30 mol% glasses were synthesized in bulk form and their ultrasonic absorption (α) curves were explored at different ultrasonic frequencies (f), 2≤ f ≤ 10 MHz, and at multiple temperatures (T) ranging from 140 to 300 K. Several features of the α–T relationship, including the mean activation energy, were dependent on composition and frequency. The α–T relationship suggested a thermally activated relaxation of movements of oxygen atoms. This relaxation was created owing to the energy transfer from ultrasonic waves to a double-well potential, in which the oxygen atoms moved. It was analyzed using the central force model of double-well states. The parameters of the model such as the mutual potential energy, loss-centers, prolongation or shrinkage of the double-well system, relaxation strength, and deformation potential were affected by differences in composition.
ISSN:0272-8842
1873-3956
DOI:10.1016/j.ceramint.2020.06.241