CaTiO_(3)添加对MgNb_(2)O_(6)微波介质陶瓷性能的影响

Effect of CaTiO_(3)Addition on Properties of MgNb_(2)O_(6)Microwave Dielectric Ceramics

为了更好的满足无线通讯高频化的要求,采用固相法制备了温度系数近零的(1–x)Mg Nb_(2)O_(6)–xCaTiO_(3)(x=0,0.02,0.04,0.08,0.12,0.16)微波介质陶瓷。研究了CaTiO_(3)的加入量对MgNb_(2)O_(6)微观结构和介电性能的影响,探究各物相的形成和烧结行为。结果表明:适当的CaTiO_(3)加入量能够促进MgNb_(2)O_(6)的烧结,降低了烧结温度。通过X射线衍射分析,CaTiO_(3)与MgNb_(2)O_(6)在高温时会反应生成CaNb_(2)O_(6)和Ti_(8)O_(15)、Ti_(2)Nb_(10)O_(29)。增加CaTiO_(3)的加入量,会降低陶瓷的品质因数Q×f,但同时会提高其介电常数εr和频率温度系数τf。当CaTiO_(3)的添加量x=0.16时,样品在1250℃烧结4 h后具有最佳的微波介电性能:εr=21.6,Q×f=86601 GHz,τf=–7.3×10^(–6)/℃。

To meet the requirements of high-frequency wireless communication,microwave dielectric ceramics of(1-x)MgNb_(2)O_(6-x)CaTiO_(3)(x=0,0.02,0.04,0.08,0.12,and 0.16)with a near-zero temperature coefficient were prepared by a solid-state method.The effect of CaTiO3 addition on the microstructure and dielectric properties of MgNb2O was investigated,and the formation and sintering behavior of each phase were analyzed.The results show that a proper addition of CaTiO,can promote the sintering of MgNb2O6 and reduce its sintering temperature.Based on the X-ray diffraction analysis,CaTiO3 can react with MgNb2O to form CaNb2O6,TigO1s,and Ti2NbioO29 at a high temperature.Increasing the proportion of CaTiO reduces the quality factor Qxf,but increases the dielectric constant&r and frequency temperature coefficient tg.When the addition amount(x)of CaTiOs is 0.16,the sample has the optimum microwave dielectric properties after sintering at 1250℃for 4h(ie.,&=21.6,Q×f=86601 GHz,and/=-7.3×10^(~6)/℃).