摘要
在BaTiO_3(BT)-Nb_2O_5-ZnO系统中引入金属Zn,对BT进行介电性能研究,以期获得低烧高介X7R陶瓷材料。研究发现,掺杂量很小时金属Zn主要与瓷料及空气中的O_2反应,晶粒变化小,容温性能能满足要求;随着掺杂量的增加,过量的Zn存在于瓷料中,使得壳层体积增大,而晶粒的增大,壳-芯体积失配,导致了介电常数迅速增加,容温性能严重恶化,改性机理可用掺杂后晶粒壳与晶粒芯体积分数的变化来解释。经配方和工艺优化后,在空气中于980℃下烧成的BaTiO_3陶瓷材料的主要性能指标达到:ε_(298K)>2700,tgδ≤1.0%,ρ≥10^(11)Ω·cm,在-55～125℃范围内最大电容量变化率不超过±15%,可用于制备低烧高介X7R多层陶瓷电容器。
In this study, Zn dust is doped into the BaTiO3 （BT）-Nb2O5-ZnO system in order to obtain the X7R materials with high dielectric capacity sintered at low temperature. The experiment results reveal that, when the amount of Zn dust is small, Zn reacts with O2 to produce ZnO. It comes hardly into the grain core, and △C/C（-55 ＋125℃）≤±15%. As more Zn dust is added, the dielectric capacity is very high, but △C/C（-55~＋125℃）≤±15% cant be got. The BaTiO3 ceramics sintered at a temperature as low as 980℃ in air atmosphere have such satisfied dielectric properties as ε298K〉2700,tgδ≤1.0%,p≥10^11Ω·cm and △C/C（-55~＋125℃）≤±15%. This material is very promising for the preparation of XTR LTCCs.
关键词
X7R
钛酸钡
金属Zn
介电性能
X7R, barium titanate,Zn dust, dielectric properties
