MgO-Al_2O_3-SiO_2-TiO_2-CeO_2系统微晶玻璃的析晶过程与微波介电性能  

Crystallization and Microwave Dielectric Properties of MgO-Al_2O_3-SiO_2-TiO_2-CeO_2 Glass-ceramics

作　　者：王乃刚[1] 罗澜[1] 陈玮[1] 张干城[1] 崔剑飞[1] 

机构地区：[1]中国科学院上海硅酸盐研究所,上海200050

出　　处：《无机材料学报》2003年第3期547-552,共6页Journal of Inorganic Materials

摘　　要：利用DTA、XRD、SEM及TEM等实验手段,研究了MgO-Al_2O_3-SiO_2-TiO_2-CeO_2系统玻璃的一个典型组成的析晶过程,并讨论了其在相变过程中微波介电性能的变化规律。研究结果表明,作为核化的先导,原始玻璃在晶化之前已经分相;在热处理过程中,金红石晶核首先在约800℃时析出;硅钛铈矿和α-堇青石则先后在约900和1100℃出现,随着热处理温度和晶化程度的提高,材料的微波介电常数不断提高,而介电损耗则不断下降,但热处理温度超过1100℃时,由于α-堇青石相的大量析出,材料的介电常数开始降低,同时由于晶粒的粗化,介电损耗略有升高。由玻璃受控析晶得到的微晶玻璃由针状金红石、颗粒状硅钛铈矿和板条状α-堇青石三种主要晶相构成,在微波频率下(10G),介电常数可在8～11范围内调控,介电损耗可<6×10^(-4),是一种有实用价值的新型微波介质材料。The crystallization process and microwave dielectric properties of MgO-Al2O3-SiO2-TiO2-Ce02 system glass-ceramics were studied by means of DTA, XRD, SEM and TEM. The results show that the parent glass has already been two-phase separated before nucleation and crystallization. The droplet phase is rich in Ti4+ and Ce4+, and the matrix phase is rich in Si4+ and A13+. During heat-treatment of the glass, rutile nucleates in the droplet phase at about 800℃ and perrierite appears at 900℃. At 1100℃, α-cordierite precipitates from the matrix phase. With increasing the heat-treatment temperatures, the crystallized volume fraction of the glass increases, which leads to the increase of the microwave dielectric constant (εr) and the decrease of the microwave loss (tgδr). However, at temperatures higher than 1100℃, δr decreases because of the precipitation of large amount of a-cordierite. At the same time, tgδ increases slightly because of the coarse structure of the crystals. The glass-ceramics obtained by crystallization of the glass have dielectric constant of 8-11, and microwave loss less than 6×10^(-4).

关 键 词：微晶玻璃 晶化 微波介电性能 

分 类 号：TQ171[化学工程—玻璃工业]