Influence of compositions on sealing temperature and properties of lead borate non-crystallizing sealing glasses

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• 作者：Yin Cheng ; Hanning Xiao ; Weiming Guo
• 关键词：Sealing glasses ; Low melting ; Thermal properties ; Glass structure
• 刊名：Materials Science and Engineering: A
• 出版年：2007
• 出版时间：25 August 2007
• 年：2007
• 卷：464
• 期：1-2
• 页码：210-215
• 全文大小：172 K

文摘

Lead borate sealing glasses, composed of 30–75PbO, 20–65B₂O₃, 0–10ZnO, 1–5Bi₂O₃ and 0–4GeO₂ in mole percent, were prepared by conventional melting-quenching method. Influence of PbO/B₂O₃ ratios and the content of oxide additives on sealing temperature, thermal expansion properties, thermal stabilities and mechanical properties of lead borate glass were investigated by IR, DSC, thermal expansion and mechanical measurement. Results indicate that the ratio of PbO/B₂O₃, both as the main glass formers, had crucial influence on network structure of lead borate glass. An appropriate proportion of PbO/B₂O₃, ZnO and GeO₂ are beneficial to lower sealing temperature and stabilize the glass against devitrification. When 1 mol % GeO₂ is introduced, the glass possesses the highest stability and lowest sealing temperature (400 °C), which is desirable for low-temperature sealing. Bi₂O₃ has little effects on the melting temperature and sealing temperature, while it helps to improve mechanical properties of lead borate glasses. Only the introduction of GeO₂ causes a little tendency for crystallization. The modified Johnson–Mehl–Avrami (JMA) equation was used to describe the crystallization kinetics of GeO₂ doped lead borate glasses. The precipitation of crystals before melting is a block for the decrease of sealing temperature. Furthermore the adjustability of the coefficient of thermal expansion caused by the additives would expand applications of lead borate glass.