KAGAKU KOGAKU RONBUNSHU, Vol.30, No.2, 233-239, 2004
Formation of lead-free sealing glasses in the quaternary system V2O5-ZnO-BaO-TeO2
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, V2O5, ZnO, BaO and TeO2 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 (V2O5-ZnO-BaO) and quaternary (V2O5-ZnO-BaO-TeO2) systems. The dependencies of these properties on composition were quantitatively characterized. The ternary system glass (50.9 mot% V2O5-18.9 mol% ZnO-30.2mol% BaO) had a low melting property, a high chemical stability (DeltaT = 101degreesC), and an amorphous structure. Furthermore, the quaternary lead-free glass (35.9 mol% V2O5-13.4 mol% ZnO-21.3 mol% BaO-29.4mol% TeO2) showed even higher thermal stability (DeltaT=135degreesC) 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.
Keywords:lead-free glass;sealing glass;low-melting point glass;V2O5-ZnO-BaO-TeO2 glass;sealing process