ZrO_2掺杂对Ba(Mg_(1/3)Ta_(2/3))O_3陶瓷结构及介电性能的影响

Effect of ZrO_2 Doping on Structure and Dielectric Properties of Ba(Mg_(1/3)Ta_(2/3))O_3 Ceramics

采用固相烧结法制备Ba(Mg_(1/3)Ta_(2/3))O_3+x%ZrO_2(BMZT)微波介质陶瓷,研究了ZrO_2掺杂对Ba(Mg_(1/3)Ta_(2/3))O_3(BMT)微波介质陶瓷结构和介电性能的影响。结果表明:陶瓷体系中存在2种相,主晶相Ba(Mg_(1/3)Ta_(2/3))O_3和附加相Ba_(0.5)TaO_3。随着x的增大,陶瓷体系的相结构由六方结构逐渐向立方结构转变,同时有序相由1:2有序结构逐渐向1:1有序结构转变。添加适量的ZrO_2可以促进液相烧结,当x=8时,陶瓷致密化烧结温度由纯相时的1 650℃以上降至1 450℃,表观密度ρ=7.568 g/cm^3,相对理论密度达到99.1%,BMZT体系拥有良好的微波介电性能:相对介电常数ε_r=25.5,品质因数与谐振频率的乘积Qf=137 600 GHz(8GHz),谐振频率温度系数τ_f=0.3×10^(-6)/℃。

Ba（Mg（1/3）Ta（2/3））O3 （BMT） ceramic with ZrO2 （BMZT） was prepared by a solid-state reaction technique. The structure and microwave dielectric properties were investigated. The results show that there are two phases in the ceramic, i.e., main crystalline phase of Ba（Mg（1/3）Ta（2/3））O3 and secondary phase of Ba0.5TaO3. The crystal structure is transformed from a hexagonal structure to a cubic structure and the ordered phase is transformed from the 1：2 ordered structure to the 1：1 ordered structure when x value increases. It is indicated that the liquid phase sintering can be improved when an appropriate amount of ZrO2 is added. Compared to pure BMT ceramic, when x = 8, the BMZT ceramic shows a lower sintering temperature, its apparent density p is 7.568 g/cm^3, its relative theoretical density is 99.1% and BMZT possesses superior microwave dielectric properties （i.e., relative dielectric constant εr of 25.5, the quality factor plus resonant frequency Qf of 137 600 GHz （8 GHz）, and the temperature coefficient of resonant frequency value zf of 0.3×10^-6/℃.