添加SrO或SnO_2对Ba_(4.5)(Nd_(0.84),Bi_(0.16))_9Ti_(18)O_(54)微波陶瓷介电性能的影响  

EFFECTS OF SrO OR SnO_2 ADDITION ON THE DIELECTRIC PROPERTIES OF Ba_(4.5)(Nd_(0.84),Bi_(0.16))_9Ti_(18)O_(54) MICROWAVE CERAMICS

作　　者：石勇[1] 靳正国[1] 程志捷[1] 魏学忠[1] 徐廷献[1] 

机构地区：[1]天津大学材料学院,先进陶瓷与加工技术教育部重点实验室,天津300072

出　　处：《硅酸盐学报》2003年第6期571-574,共4页Journal of The Chinese Ceramic Society

摘　　要：对Ba4.5(Nd0 .84,Bi0 .1 6 ) 9Ti1 8O54 (BNBT)系微波陶瓷进行了组成改性的研究。添加不同量的SrO或SnO2 于主相材料中 ,分别替代Ba或者Ti,合成条件为 110 0℃下保温 3h ,粉碎、成型后 ,在 12 70℃下保温 3h烧成。在 10GHz下用谐振腔法测量了材料的介电常数εr和机械品质因数Q ,在 2 0～ 90℃范围测量了频率温度系数τf。结果表明 :Sr,Bi复合掺杂能够使BNBT材料保持较高的介电常数 ,同时Qf值 (机械品质因数Q与测量频率之积 )由 5 899GHz上升到 92 5 9GHz,而少量的SnO2The microwave dielectric properties and microstructure of Ba 4.5(Nd 0.84,Bi 0.16) 9Ti 18O 54(BNBT) ceramics with SrO or SnO 2 additives were investigated. BNBT precursor powders doped with different contents of SrCO 3or SnO 2 for the substitution of Ba or Ti were synthesized at 1 100 ℃ for 3h and then BNBT samples were sintered at 1 270 ℃ for 3 h. The dielectric constant ε r and the quality factors Q were measured at 10 GHz by using resonance cavity method and the temperature coefficients of resonant frequency were also measured in the temperature range of 20-90 ℃. Experimental results indicate that the substitution of 0.04 mol Sr ions for Ba ions can improve Qf values from 5 899 GHz to 9 259 GHz and keep high dielectric constant. It is explained that the substitution reduces the inner strain, which is caused by the larger Ba ions occupying the sites in the perovskite blocks for Nd ions, because the ionic radius of the Sr ion is smaller than that of the Ba ion. The doping with small amount of Sn is helpful to decrease τ f from 28.7×10 -6/K to 13.5×10 -6/K and improve dielectric constant by substitution of Sn ion for Ti ion at the site of Ti-O octahedral, which results in the increase of cell volume of the tungsten bronze-type structure.

关 键 词：钛酸钡钕 微波陶瓷 氧化锶 氧化锡添加 介电性能 

分 类 号：TQ174[化学工程—陶瓷工业]