溶胶-凝胶法制备(Ca1-xMgx)SiO3陶瓷及其微波介电性能

以硝酸钙、硝酸镁、正硅酸乙酯为先驱体, 利用溶胶-凝胶法合成(Ca1-xMgx)SiO3(x=0.1、0.2、0.3、0.4、0.5)陶瓷粉体, 研究了Mg2+取代Ca2+对陶瓷物相组成、烧结特性以及微波介电性能的影响规律. 结果表明, Mg2+在CaSiO3中的最大固溶度不超过0.2；随着Mg2+对Ca2+取代量的增加, 陶瓷在烧结后的主晶相出现从CaSiO3相向CaMgSi2O6相的转变,陶瓷的烧结特性及介电性能出现先增加后下降的趋势；当x=0.3 时, 陶瓷体中CaSiO3相与CaMgSi2O6相共存, 克服了单相CaSiO3或CaMgSi2O6易成片长大的缺点,有效减少了陶瓷中残留的气孔, 提高烧结体致密性. (Ca0.7Mg0.3)SiO3在1320 益烧结后介电常数为6.62, 品质因数为36962 GHz.

Synthesis and Microwave Dielectric Properties of (Ca1-xMgx)SiO3 Ceramic by Sol-Gel Process

Using Ca(NO3)2·4H2O, Mg(NO3)2·6H2O and Si (OC2H5)4 as precursors, (Ca1-xMgx)SiO3 powders were prepared by sol-gel method with varying x (0.1, 0.2, 0.3, 0.4, 0.5). The phase constitution, sintering characteristic and dielectric properties of (Ca1-xMgx)SiO3 ceramics were studied. The results showed that the solubility limitation of Mg2+ in CaSiO3 was below 0.2 and CaSiO3 phase was transformed into CaMgSi2O6 phase with substituting Ca2+ by Mg2+. When x was 0.3, the growth of grains was restrained and pores were decreased due to the coexistence of CaSiO3 and CaMgSi2O6, and then the ceramic density was enhanced. The dielectric constant and quality factor of (Ca0.7Mg0.3)SiO3 ceramic sintered at 1320 ℃ were 6.62 and 36962 GHz, respectively.