Fabrication and characterization of B2O3–Al2O3–Na2O glass system for transparent dielectric layer

Glasses within the B2O3–Al2O3–Na2O system were examined as potential replacements for PbO-based glass frits with low firing temperature (500–600 °C) for transparent dielectric layer of plasma display panel (PDP). The glasses were evaluated for glass transition (Tg), softening temperature (Tf), thermal coefficient of expansion (α) and dielectric constant (ε). The dielectric constant of these glasses was also compared with theoretical data calculated by Appen and Breskerʹs equation. Tg of the glasses varied between 330 and 460 °C and Tf was in the region of 350–500 °C. The thermal coefficient of expansion ranged from 7×10−6 to 10×10−6 K−1. The dielectric constant of these glasses was 6–8 within the region of the theoretical value. The Tg, Tf, α, ε of the selected glass, which was used to prepare transparent dielectric layer in 20 μm thickness, were found to be 449 °C, 476 °C, 8.284×10−6/k, 6.84, respectively. All the results suggest that B2O3–Al2O3–Na2O glasses would be suitable as a potential candidate for Pb-free dielectric layer in PDPs.