Abstract
Lead-free glasses with a low melting point and good chemical durability are desirable for the sealing process in the ceramic and electronic fields. In this study, B2O3, ZnO, BaO, and TeO2 or Bi2O3 were used to prepare lead-free sealing glasses with a low melting temperature. The glass forming region, glass transition temperature, softening temperature, thermal stability, thermal expansion property, and X-ray properties were investigated in detail in the ternary (B2O3-ZnO-BaO) and quaternary (B2O3-ZnO-BaO-TeO2 or Bi2O3) systems. The dependencies of these properties on composition were quantitatively characterized. The ternary system glass (30 mass% B2O3-20 mass % ZnO-50 mass% BaO) had a low melting property, a high chemical stability (ΔT : 110°C), and an amorphous structure. Furthermore, the quaternary lead-free glass (10 mass% B2O3-6.7 mass% ZnO-16.7 mass% BaO-66.6 mass% TeO2 or Bi2O3) showed even higher thermal stability (Δ T : more than 200°C) and good bonding and sealing properties. The quaternary glass also had a high water resistance compared to commercial lead glass. In a sealing test with a plane fluorescence lamp incorporated in a digital camera, perfect sealing was achieved. The prepared lead-free glass showed an excellent performance as a substitute for the commercial lead glass.
