K2O含量对B2O3-Al2O3-Na2O玻璃结构及物理性能的影响

选取B_2O_3-Al_2O_3-Na_2O三元玻璃系统,研究改变玻璃系统中K_2O的含量对硼酸盐低熔点封接玻璃性能的影响。通过XRD、DTA等手段对玻璃样品的膨胀系数、转变温度、软化温度、电阻率、介电常数等性能进行了测试。结果表明:在B_2O_3-Al_2O_3-Na_2O三元玻璃系统中,随着K_2O含量的增加,硼酸盐玻璃的膨胀系数呈先下降后上升的趋势,在K_2O含量位于5 mol%左右时,硼酸盐玻璃的膨胀系数小幅下降,这是硼反常现象的体现。K_2O含量在7～8 mol%左右时,膨胀系数出现最低值。玻璃的体积电阻率和介电常数的变化也存在着硼反常现象,随着K_2O含量的增加,均呈现先下降再上升后又下降的趋势。玻璃的转变温度T_g和软化温度T_f的变化趋势基本一致,均呈现先下降后上升再下降的趋势。

Effect of K_2O Content on the Structure and Physical Properties of B_2O_3-Al_2O_3-Na_2O Glass

By adopting B2O3-Al2O3-Na2O ternary glass as research object,the effect of K2O content on the properties of low melting point borate sealed glass was studied.The properties of the glass samples,such as thermal expansion coefficient,transition temperature,softening temperature,resistivity and dielectric constant were measured by XRD and DTA.The results show that in the B2O3-Al2O3-Na2O ternary glass,with the increase of K2O content the thermal expansion coefficient of borate glass decreases first and then rises up.When the concentration of K2O is about5mol%the thermal expansion coefficient of borate glass decreases slightly.This is an embodiment of the abnormal phenomenon of boron.When the K2O concentration is about7~8mol%,the thermal expansion coefficient reaches the lowest value.The variation of volume resistivity and dielectric constant of glass also shows boron paradox.With the increase of K2O content,both of them show a trend of decrease first,then rise and then decline.The change trend of glass transition temperature Tg and softening temperature Tf are basically the same.Both of them decrease first,then increase and then decrease again.