Lead-free low-melting point sealing glass in SnO-CaO-P_2O _5 system

摘要

Development of lead-free low-melting point sealing glass with properties such as low coefficient of thermal expansion (CTE), low glass transition temperature (T_g), low softening temperature (T_f), low cost, high electrical resistance and high chemical stability, has been under strong market demands. Research on the development of lead-free low-melting point sealing glass in SnO-CaO-P_2O_5 (SCP) system was carried out. A large glass formation composition region in the SCP ternary system was found. The SCP glass, possessing properties of low T_g (< 690 K) and high thermal stability, is suitable for low-to-mid temperature sealing applications in the industry. Its CTE is in the range 90-100 × 10~(-7) K~(-1), suitable for most device substrates. SiO _2 doping with different amounts decreases the CTE and increases the electrical resistance linearly, and improves the water durability by exponentially decreasing the relative mass loss. However, the CTE and the electrical resistance of the glass doping with B_2O_3 both show a maximum at about 2 mol% B_2O_3 doping.