ZrO2/TiO2/ZrO2+TiO2三种添加剂对CaO-BaO-SiO2-B2O3封接玻璃析晶及抗折强度的影响

The Effects of ZrO_2/TiO_2/ZrO_2+TiO_2 three additives on the crystallization and flexural strength of CaO-BaO-SiO_2-B_2O_3 sealing glass

通过在CBSB(CaO-BaO-SiO_2-B_2O_3)中添加不同添加剂(无添加剂、TiO_2、ZrO_2、TiO_2和ZrO_2复合),利用熔融-退火法制备CBSB系封接玻璃,分别标记为CBSB0、CBSB1、CBSB2、CBSB3。利用差热分析、XRD分别表征不同添加剂对该体系玻璃析晶温度、析晶衍射强度的影响;利用SEM观察晶体的形貌,同时利用抗折强度来探究玻璃析晶前后力学性能的变化。结果表明:在CBSB中,少量(2.8wt.%)添加剂以[TiO_4]和[ZrO_4]四面体的形式存在于玻璃的网络结构,促进了玻璃的析晶温度向高温移动(析晶温度最高者是CBSB3,其析晶温度为868℃)。XRD的结果显示添加剂的引入在一定程度上抑制了BaAl_2Si_2O_8和Ba_2Ca(B_3O_6)_2的形成,且TiO_2的添加抑制效果最明显。结合SEM与抗折强度可以看出,玻璃内析出片状晶体,提升了玻璃的抗折强度,CBSB2在800℃热处理后抗折强度最大,其值为125.26 MPa。

The CaO-BaO-SiO2-B2O3(CBSB)sealing glass with adding different additives such as no additives,TiO2 and ZrO2 as additives and TiO2 and ZrO2 composite additives,was obtained using the method of melting annealing,which marked respectively as CBSB0、CBSB1、CBSB2、CBSB3.The effects of different additives on the crystal temperature and crystal diffraction intensity of the glass were characterized by differential thermal analysis and XRD,respectively.The morphology of crystal was observed by SEM and the changes of mechanical properties before and after glass crystallization were investigated using flexural strength.The experimental results showed that 2.8%additive exist in the CBSB glass network structure in the form of[TiO4]and[ZrO4]tetrahedron which promote the crystallization temperature of glass to move to high temperature,and CBSB3 possess the highest crystallization temperature among four glasses,whose value is 868°C.The XRD result indicated that the additive inhibited the formation of BaAl2Si2O8 and Ba2Ca(B3O6)2 to a certain extent.Moreover,the addition of TiO2 had the most obvious inhibitory effect.It also can be seen from the combination of SEM and flexural strength that the flaky crystals are precipitated in the glass which increase the bending strength comparing with that of the corresponding base glass,and CBSB2 has the highest bending strength at heat-treatment of 850°C,whose value is 125.26 MPa.