TiO_2对MgO-Al_2O_3-SiO_2-TiO_2-La_2O_3系微晶玻璃相变和微波介电性能的影响  

Effect of TiO_2 on Crystallization and Microwave Dielectric Properties of MgO-Al_2O_3-SiO_2-TiO_2-La_2O_3 Glass-ceramics

作　　者：王慧娟[1] 李泊涛[1] 林慧兴[1] 姚晓刚[1] 陈玮[1] 罗澜[1] 

机构地区：[1]中国科学院上海硅酸盐研究所中国科学院无机功能材料与器件重点实验室,上海201800

出　　处：《硅酸盐学报》2015年第4期498-503,共6页Journal of The Chinese Ceramic Society

摘　　要：采用高温熔融法和-步法微晶化热处理制备了MgO-Al_2O_3-SiO_2-TiO_2-La_2O_3(MASTL)微晶玻璃。利用差热分析、X射线衍射、扫描电子显微镜和网络分析仪等手段研究了TiO_2含量对MASTL玻璃析晶相变过程、显微结构和微波介电性能的影响。结果表明,在玻璃热处理过程中先后有硅钛铈矿、金红石(TiO_2)、镁铝钛酸盐、尖晶石(MgAl_2O_4)和堇青石(Mg_2Al_4Si_5O_(18)))5种晶相析出。其中,镁铝钛酸盐含量相对较低,尖晶石是一个亚稳过渡相。随着TiO_2含量的增多,原始玻璃的析晶倾向增大,初晶相硅钛铈矿和主晶相金红石的析晶温度显著降低,而尖晶石的析晶温度升高;材料的介电常数和谐振频率温度系数均显著增大,这主要由样品中具有高介电常数(100.0)和较大正温度系数(400×10^(-6)/℃)的金红石相含量增多引起。同时,由于高品质因数相堇青石(40000GHz)的析出量略有减少,品质因数有所降低。Glass-ceramics were fabricated from MgO-Al_2O_3-SiO_2-TiO_2-La_2O_3(MASTL) system by a molten method and subsequent one-step crystallization heat-treatment.The effect of TiO_2 on the crystallization,microstructure and dielectric properties of the glass-ceramic material was investigated by differential scanning calorimetry,X-ray diffraction,scanning electron microscopy,energy dispersive X-ray spectroscopy and network analysis,respectively.The results show that the glass-ceramic consists of multi-crystalline phases,i.e.,perrierite,cordierite,magnesium aluminotitanate(MAT),rutile and spinel(MgAl)2O_4).Among them,the content of MAT is low and spinel belongs to metastable intermediate.The crystallization tendency of the original glass becomes stronger when TiO_2 content increases.Moreover,the crystallization temperature of perrierite and rutile descends significantly,while the crystallization temperature of spinel increases.The increase of dielectric constant and temperature coefficient of resonant frequency(τ_f) of the glass-ceramic is mainly due to the presence of more rutile with greatε_r and tremendous positive τ_f,and the slight decrease of quality factor(Q×f) is correlated to the decrease of cordierite with great Q×f.

关 键 词：微晶玻璃 镁铝硅钛镧系 析晶 相变 介电性能 

分 类 号：TQ171.733[化学工程—玻璃工业]