(1-x)Ba(Mg1/3Nb2/3)O3-xBaSnO3陶瓷的微波介电性能

用传统陶瓷制备方法制备了(1-x)Ba(Mg1/3Nb2/3)O3-xBaSnO30.0≤x≤0.3,(1-x)BMN-xBS]体系微波介质陶瓷,研究了该陶瓷的微观结构和微波介电性能.用X射线衍射仪研究陶瓷的晶体结构.用扫描电镜观察陶瓷的显微结构.用网络分析仪测试陶瓷的微波介电性能.结果表明:晶格常数c和a均随x值的增加而增加;晶格常数比(c/a)随x值的增加而减小.当x≥0.1时,1∶2有序衍射峰消失.陶瓷的平均晶粒尺寸在0.7～2 μm之间.随x值的增加,陶瓷的相对介电常数(εr)和谐振频率温度系数(τr)呈线性减小;品质因数与谐振频率的乘积(Qf)呈非线性变化.当x=0.15时,Qf达到最大值,为86 200 GHz.当x=0.3时,在此体系中可以获得τf接近零的微波介质陶瓷Ba(Sn0.3Mg0.233Nb0.467)O3,其微波介电性能如下:εr=26.1;Qf=42 500GHz;τr=4.3×10-6/℃.

MICROWAVE DIELECTRIC PROPERTIES OF(1-x)Ba(Mg1/3Nb2/3)O3-xBaSnO3 CERAMICS

The(1-x)Ba(Mg1/3Nb2n)O3-xBaSnO3(0.0≤x≤0.3,(1-x)BMN-xBS)ceramics were prepared by the conventional ceramies preparation technique.The microstructures and microwave dielectric properties of(1-x)BMN-xBS ceramics were investigated.X-ray diffraction was used to investigate the crystal structures of the ceramics.Scanning electron microscope was utilized to observe the microstructures of the ceramics.The microwave dielectric properties were measured using a network analyzer.The results show that the lattice constants of c and a both increase with the increase of x.However,the lattice constant ratio(c/a)decreases as x increases.The average grain size of the ceramics was in the range of 0.7-2μm.The relative dielectric constant(εr)and resonance frequency temperature coefficient (τf)value of the ceramics decrease linearly.However,the quality factor plus resonance frequency(Qf)values vary non-linearly with composition.The highest Qf value achieved in this investigation was about 86 200 GHz,whicho ccurred when x=0.15.A new microwave dielectric ceramic with near-zero τf in the(1-x)BMN-xBS system was attained when x=0.3.The Ba(Sn0.3Mg0.233Nb0.467)O3 solid solution ceramics exhibit good microwave properties:εr=26.1,Qf=42 500 GHz and τf=4.3×10-6/℃.