晶核剂对烧结法制备Li2O-A12O3-SiO2系微晶玻璃晶化过程的影响

Influence of Nucleating Agents on Crystallization of Li2O-A12O3-SiO2 System Glass Ceramics Prepared by Sintering Method

采用差热分析(DTA),X射线衍射分析(XRD),扫描电镜(SEM)等分析手段研究了P2O5和TiO2+ZrO2+P2O5复合晶核剂对Li2O-A12O3-SiO2(LAS)系微晶玻璃的形核和晶化的影响。结果表明,烧结法制备LAS系微晶玻璃时,晶核剂种类及含量只会影响晶体的形貌,并不会改变其晶相组成,即使不添加任何晶核剂,依然能获得具有一定结晶度的制品,适量晶核剂的加入,降低析晶活化能,进而可以促进微晶玻璃在较低温度下析晶。其中P2O5有利于析出纤维状的β-锂辉石固溶体,而TiO2、ZrO2则有利于析出颗粒状的β-锂辉石固溶体,且随着ZrO2含量的增大,晶体颗粒减小。当微晶玻璃不添加晶核剂时,其热膨胀系数为0.59×10-6/℃,强度达到44.31MPa,当TiO2、ZrO2及P2O5的添加量为2%、4%、4%时,微晶玻璃的热膨胀系数为0.91×10-6/℃,强度达到85.93MPa。

The influence of multi-nucleating agents(P2O5 with TiO2+ZrO2+P2O5)on nucleation and crystallization of Li2O-A12O3-SiO2(LAS)system glass ceramics was investigated by differential thermal analysis(DTA),X-ray diffraction(XRD)and scanning electron microscope(SEM).Results showed that when the LAS system glass ceramics were prepared by sintering method,the type and content of nucleating agent could affect the crystal morphology,but didn’t change the phase composition.evenwithout any nucleating agent,the product with a certain degree of crystallinity would be obtained.Adding a moderate amount of nucleating agent can reduce the activation energy to promote the crystallization of glass ceramics at a lower temperature.In this research,P2O5 was beneficial to the crystallization ofβ-spodumene solid solution in fiber shape,while TiO2 and ZrO2 were in favor of the crystallization ofβ-spodumene solid solution in particle shape.Along with the increase of ZrO2 content,the particle size was decreased.When the addition content of Ti O2,ZrO2,P2O5 was 2%,4%and 4%respectively,the coefficient of thermal expansion of glass ceramic was 0.91×10-6/°C,and the strength reached 85.93 MPa.