Effect of Gd2O3 on the Structure and Dielectric Properties of Phosphobismuth Glass

In this study, 60P(2)O(5)-25Bi(2)O(3)-(10-x)CaO-5Sb(2)O(3)-xGd(2)O(3) (x = 0, 1, 2, 3, 4 and 5) multi-component oxide glass was prepared by conventional high-temperature melting method. XRD spectrum indicates that all samples with x <= 3 mol% formed homogeneous glass, but the glass samples of x= 4 and 5 mol% had crystallized. The density, glass transition temperature (T-g), and softening temperature (Tf) of the doped 0-4 mol% Gd2O3 glass increased steadily, and the coefficient of thermal expansion (CTE) and molar volume decrease continuously. The IR spectra found that the glass network was denser and enhanced the structure when the sample contained 3 mol% Gd2O3. Homogeneous glass doped with 1-3 mol% Gd2O3 has better corrosion resistance than crystallized glass doped with 4 mol% Gd2O3. Dielectric constant (sigma) and dielectric loss (tan alpha) decrease as the network becomes compact. The glass containing 3 mol% Gd2O3 had a compact network structure and lower dielectric properties (sigma=5.01, tan alpha=2.6 x 10(-3)). The results show that Gd acts an important role in enhancing he cross-links between the phosphate chains and nd reducing the dielectric properties of the glass.