采用传统固相合成法制备了Li2(Mg1/2Zn1/2)SiO4微波介质陶瓷,并系统研究了该陶瓷的相成分、微观形貌、微波介电性能与烧结温度之间的影响关系。XRD结果表明:在1100~1180℃温度烧结,该体系的主晶相均为Li2(Mg0.8Zn0.2)SiO4,但同时也伴随有少量的MgSiO3第二相。SEM结果表明:随着烧结温度的升高,样品的晶粒尺寸不断增加,尤其是当烧结温度为1180℃时,有些大晶粒出现了开裂现象,这会在一定程度上降低样品的品质因数(Q·f)。因此,对于微波介电性能,随着烧结温度的增加,Li2(Mg1/2Zn1/2)SiO4陶瓷的Q·f值呈先增后减趋势,而相对介电常数(εr)的数值较为稳定;此外,该体系谐振频率温度系数(τf)随烧结温度的增加逐渐向正值方向移动。当在1160℃烧结4h时,Li2(Mg1/2Zn1/2)SiO4陶瓷可获得最佳的微波介电性能:εr=6.09,Q·f=21616GHz(f=11.62GHz)和τf=–64.34×10–6/℃。
Li2(Mg1/2Zn1/2)SiO4ceramics were prepared by the conventional solid-state reaction process.The phase composition,microstructures and microwave dielectric properties of the Li2(Mg1/2Zn1/2)SiO4ceramics were investigated systematically.The XRD results show that the present ceramic systems are mainly composed of Li2(Mg0.8Zn0.2)SiO4(mainphase)and MgSiO3(second phase)in the range of sintering temperatures from1100℃to1180℃.The SEM images illustrate that the average grain sizes increase with increasing sintering temperatures,especially some larger grains accompanied by the cracks could be observed as sintering at1180℃,which has a negative effect on quality factor(Q·f).Thus,for the microwave dielectric properties,the Q·f values firstly increase and then decrease,while the values of permittivity(εr)are basically stable with an increasing of sintering temperature.Additionally,the temperature coefficient of resonant frequency(τf)gradually shifts to the positive direction as increasing sintering temperature.Wherein,the Li2(Mg1/2Zn1/2)SiO4ceramics sintered at1160℃for4h have an excellent microwave dielectric properties ofεr=6.09,Q·f=21616GHz(at11.62GHz)andτf=-64.34×10-6/℃.