Thermal properties of glasses based on Bi₂O₃ for Pb free solder glasses

Abstract

With the aim of developing Pb-free Bi₂O₃-based new solder glasses; glass forming region, glass transition temperature, crystallization temperature, thermal expansion, and water resistance of Bi₂O₃-BaO-B₂O₃ ternary glass system were investigated. The roles of Bi₂O₃ in this ternary glass were also discussed. The results showed that glass transition temperature and thermal expansion coefficients of the ternary glasses were in similar range as compared to those solder glass consisting PbO. The water resistance of ternary glass was almost the same as compared to window glass, but it is higher than solder glass containing PbO. The glass transition temperature of ternary glass was dependent on average bond strength. Our results also showed that as the amount of Bi₂O₃ increased, the average bond strength was decreased which lead to decrement of glass transition temperature. These results suggested that Bi₂O₃ plays an important role as glass network former in the glass system.