Effect of Si/B ratio of low dielectric glass on its structure, properties and sealing mechanism for high-frequency communication

Abstract

Sealing glasses are widely used in the electronics industry to provide electrical insulation and form connectors with a range of metals. In this study, a range of SiO₂–B₂O₃–Al₂O₃–R₂O sealing glasses with low dielectric constant and low dielectric loss were prepared using conventional melting and quenching techniques, followed by powder processing. The effects of the SiO₂/B₂O₃ (Si/B) molar ratio on the structure, properties, and sealing mechanism of the glasses were investigated. The results indicated that the network structure of the glass system initially became more compact and subsequently relaxed with an increase in the Si/B ratio. The dielectric constant of the sealing glasses increased with increasing Si/B ratio, whereas the coefficient of thermal expansion and dielectric loss exhibited an initial decrease, followed by an increase. Optimal structural compactness was observed at a Si/B ratio of 2.76, resulting in a lower dielectric constant (4.04@10 GHz) and the lowest dielectric loss (12×10⁻⁴@10 GHz). Following sealing, the chemical bonds in the metal surface layer gradually shifted from metallic to ionic–covalent bonds, which facilitated a robust glass–metal bond. These sealing glasses are well suited for RF connector applications and hold promising market potential in the realm of high-frequency communication.