Ba1-3x/2Lax(Mg1/3Ta2/3)O3陶瓷的微波介电性能

采用固相合成法制备了Ba1-3x/2Lax(Mg1/3Ta2/3陶瓷,研究了La掺杂对钽镁酸钡的结构和微波介电性能的影响.结果表明:A位取代能改进其烧结性能.在x≤0.02时,烧结样品为单相的钙钛矿结构,B位离子1:2有序;当x>0.02时出现第二相Ba0.5TaO3.B位离子有序度随着x的增大先增加后减小,在x=0.04时出现最大值.x≤0.02时介电常数变化较小,而后其值逐渐增大.品质因数与谐振频率的乘积(Q×f)值随着x的增大先增大后减小,在x=0.02时取得最大值;谐振频率温度系数(τf)值随着x增大而增大.

MICROWAVE DIELECTRIC PROPERTIES OF Ba1-3x/2Lax(Mg1/3Ta2/3)O3 CERAMICS

The Ba1-3x/2Lax(Mg1/3Ta2/3)O3 (BMT) ceramics were prepared by a solid state reaction process. Effects of La doping on the structure and microwave dielectric properties of BMT ceramics were investigated. The results indicate that the La doping on the A-site improved the sinterability of BMT ceramics. The La-doped samples maintain a single perovskite phase with B-site 1:2 ordering when x≤0.02,and a Ba0.5TaO3 second phase forms when x>0.02.The B-site ordering degree increases with the increase of x up to x=0.04 and then decreases with the further increase of x. The dielectric constant varies little for the x≤0.02 samples and increases slightly with the further increase of x. The quality factor plus resonant frequency (Q×f) increases with the increase of x up to x=0.02 and then decreases with the further increase of x. The temperature coefficient of resonant frequency (τf) value increases with the increase of x.