Zn_(1–x)Ca_x(Ti_(0.6)Zr_(0.4))Nb_2O_8陶瓷的微波介电性能

Microwave Dielectric Properties of Zn_(1–x)Ca_xTi_(0.6)Zr_(0.4)Nb_2O_8 Ceramics

采用传统固相反应法制备Zn_(1–x)Ca_xTi_(0.6)Zr_(0.4)Nb_2O_8(x=0.05,0.10,0.20,0.30)微波介质陶瓷,研究了不同Ca^(2+)取代量对Zn_(1–x)Ca_xTi_(0.6)Zr_(0.4)Nb_2O_8陶瓷的物相组成、显微结构及微波介电性能的影响,利用X射线衍射仪、扫描电子显微镜和网络分析仪等对其晶体结构、微观形貌及微波介电性能进行表征。结果表明:Ca^(2+)取代Zn^(2+)会导致Ca Nb_2O_6第二相的形成,且随Ca^(2+)含量的增加,ZnTiNb_2O_8相含量减少;Ca Nb_2O_6相的含量增加,导致Zn_(1–x)Ca_xTi_(0.6)Zr_(0.4)Nb_2O_8陶瓷的介电常数和品质因数减小,谐振频率温度系数向正方向移动。当x=0.3时,Zn_(1-x)Ca_xTi_(0.6)Zr_(0.4)Nb_2O_8陶瓷在1 140℃烧结并获得最佳微波介电性能:ε_r=30.42,Q×f=47 280 GHz,τ——f=–25.37×10^(–6)/℃。

Zn1–xCaxTi0.6Zr0.4Nb2O8(x=0.05,0.10,0.20,0.30)microwave dielectric ceramics were prepared by a solid-state reaction method.The effect of Ca2+substitution amount on the phase composition,microstructure and microwave dielectric properties of Zn1–xCaxTi0.6Zr0.4Nb2O8 ceramics was investigated by X-ray diffraction,scanning electron microscopy and network analysis,respectively.The results show that Ca2+substitution of Zn2+leads to the formation of the second phase of CaNb2O6,the content of ZnTiNb2O8 phase decreases and the content of CaNb2O6 phase increases with the increase of Ca2+content,leading to the decrease of dielectric constantεr and quality factor Q′f of Zn1–xCaxTi0.6Zr0.4Nb2O8 ceramics,and the temperature coefficient of resonant frequencyτf shifting to a positive direction.The optimum microwave dielectric properties(i.e.,εr=30.42,Q′f=47 280 GHz,τf=–25.37×10–6/℃)are obtained when Zn1–xCaxTi0.6Zr0.4Nb2O8 ceramic is sintered at 1 140℃as x=0.3.