Thermal and mechanical properties of lead-free transparent dielectric materials for plasma display panels

The transparent dielectric materials for front panel in PDPs require good thermal expansion matching to glass substrate. Lead oxide ( PbO) has been broadly utilized in transparent dielectric layers for low-temperature firing process. According to environmental and human health problem, however, Pb-based glass ceramics are no longer suitable for transparent dielectric layers. Glass with the Bi-based system was examined as a potential replacement for Pb-based glass. Softening point and coefficient of thermal expansion of the glass were at 520 degrees C and 8.5 x 10(- 6)/degrees C, respectively. Optimum sintering temperature for the highest densification was at 560 degrees C, which indicated the highest flexural strength value derived from the lowest pore volume fraction. In addition, transmittance of specimen sintered at 560 degrees C was about 90% in a visible light region. These results suggested that Bi-based glass would be suitable as an alternative to Pb-based dielectric layer in PDPs.