Studies On The Glass Forming Ability Of V₂O₅-B₂O₃-TeO₂ Systsem

Sealing materials are widely used and in huge demand. As a kind of sealing materials, sealing glasses have been widely applied to vacuum electron technology, microelectronics technology, energy, automobile industry, etc because of its good heat resistance, electrical insulation, high mechanical strength and chemical stability.The traditional sealing glasses systems contain a large amount of lead, which is seriously harmful to environment. At the same time, the operating temperature of sealing glasses used in electronic products such as integrated circuit chips, in which most parts are not allowed to operate on high temperature is required as low as possible. So now, the sealing glasses have a trend of development of lead free and low temperature.According to the development trend of the sealing glasses, this dissertation is going to make a research on the glass forming ability of V₂O₅-B₂O₃-TeO₂ system, so that to provide the reliable theory basis of the research and exploitation of good performance, low temperature and lead free sealing glasses system. In this paper, select 63 composition points in V₂O₅-B₂O₃-TeO₂ system uniformly, and each component is in 10mol % changes for step length. Melt and quench the glass batch to obtain the samples, and then the thermal properties and characteristic temperature of the quenched product were tested. Glass forming ability, thermal properties and characteristic temperature were studied. The impact of glass characteristic temperature by the content of B₂O₃ and TeO₂ was discussed.The results indicates that V₂O₅-B₂O₃-TeO₂ ternary system has lower melting temperature .There are three different crystalline regions and a broader area of glass forming region. V₂O₅-B₂O₃-TeO₂ system's glass forming zone is:V₂O₅:0～ 70mol%;B₂O₃:0～30mol%;TeO₂:30～100mol%.V₂O₅-B₂O₃-TeO₂ ternary system has lower melting temperature and sealing temperature, so the system is one of the ideal system of Lead-free low-temperature sealing glass .The glass samples of this system have a more ideal one which essentially consists of 10mol% of V₂O₅, 20mol% of B₂O₃, and 70mol% of TeO₂ .The expansion coefficient, softening temperature and sealing temperature of this system were: 115×10-7K-1, 280℃and 355℃respectively.Maintaining the content of B₂O₃ (10%) unchanged, with the content of TeO₂ increased, both of the glass melting temperature and sealing temperature are lower. The glass softening temperature (Td) ,transition temperature (Tg) and coefficient of expansion almost showed two high, middle low.Maintaining the content of TeO₂ (70%) unchanged, coefficient of expansion and melting temperatures increased with the content of B₂O₃ was first decreased and then increased. The size of melting temperature can not decide the size of sealing temperature.