Preparation and study of dielectric proprieties of glassy materials in ternary system Bi2O3-Nb2O5-P2O5

Phosphate glasses of the ternary system Bi2O3-Nb2O5-P2O5 were studied in two compositional series, namely xBi(2)O(3)-5Nb(2)O(5)-(95-x)P2O5 (serie B), with x = 10-17,5 mol% Bi2O3, and 10Bi(2)O(3)-xNb(2)O(5)-(90-x) P2O5 (serie N), with x = 2,5-15 mol% Nb2O5. Seven homogeneous glassy samples were prepared, and their amorphous structure were confirmed by X-ray diffraction. The dielectric properties such as dielectric constant (epsilon') and dielectric loss (tan delta) were determined as a function of temperature ranging from 100 degrees C to 500 degrees C at a fixed applied frequency of 16 kHz. Replacing P2O5 by Bi2O3 or Nb2O5 decreases the dielectric parameters in both series. These results are attributed to the increase in the cross-link density and the rigidity of the glass, leading therefore to a decrease of the polarization. The usual increasing behavior of (epsilon') and (tan delta) with temperature may be explained by the augmentation of the orientation polarization and the electrical conduction losses values. (C) 2019 Elsevier Ltd. All rights reserved.