Effects of ZnO and cordierite contents on the wetting properties of a Bi₂O₃–ZnO–B₂O₃ glass composite as a low-melting sealing glass

The wetting properties of Bi₂O₃–ZnO–B₂O₃ glass composite materials with different ZnO and cordierite contents were investigated upon melting them and thermally treating them at 1300 °C and 430 °C, respectively. The density of a 48%Bi₂O₃–24%ZnO–22% B₂O₃ glass composite was 7.30 g/cm³, which is 99.3% of its theoretical density; its glass softening temperature was 413.2 °C. The addition of cordierite improved the adhesion of the glass by acting as a filler, thus lowering its coefficient of thermal expansion. Specifically, by adding 0–15% cordierite, the coefficient of thermal expansion of the Bi₂O₃–ZnO–B₂O₃ glass was reduced from 10.6 × 10^–6 to 7.5 × 10^–6 /K. X-ray diffraction and transmission electron microscopy studies confirmed that the glass was not crystallized, but rather a composite. This study demonstrates that the Bi₂O₃–ZnO–B₂O₃ glass composite developed herein is an environment-friendly lead-free material that can be sintered at 430 °C without losing its tempered glass function; therefore, this material shows promise for applications in architecture, electronic devices, and home appliances.