TiO2添加量对Zn0.8Mg0.2ZrNb2O8微波介质陶瓷结构和性能的影响

Effect of TiO_2 Addition Amount on Structure and Microwave Dielectric Properties of Zn_(0.8)Mg_(0.2)ZrNb_2O_8 Ceramic

采用传统固相合成工艺制备（1–x）Zn0.8Mg0.2ZrNb2O8-xTiO2（ZMZNT, x=0.00, 0.20, 0.40, 0.50, 0.60, 0.65, 0.70, 0.80）微波介质陶瓷，研究了TiO2 添加量对Zn0.8Mg0.2ZrNb2O8 陶瓷烧结行为、相结构、微观结构以及微波介电性能的影响。结果表明：随着TiO2 添加量增加，ZMZNT 陶瓷的烧结温度逐步下降。当x=0-0.5 时，形成了Zn0.8Mg0.2（Zr,Ti）Nb2O8 固溶体；而当 x=0.6-0.8时，陶瓷体系发生了复杂物相变化，微观形貌也呈现对应的变化规律。随着TiO2 添加量的增加，ZMZNT 陶瓷相对介电常数εr 逐渐增大，品质因数Q×f 呈下降趋势，谐振频率温度系数τf 呈上升趋势。当x=0.65 时，0.35Zn0.8Mg0.2ZrNb2O8-0.65 TiO2陶瓷在1 170 ℃烧结4 h，可以获得较佳的微波介电性能：εr =36.7，Q×f = 37 432 GHz，τf =7.12 ×10^-6/℃。

（1–x）Zn0.8Mg0.2ZrNb2O8-xTiO2（ZMZNT, x=0.00, 0.20, 0.40, 0.50, 0.60, 0.65, 0.70 and 0.80） microwave dielectric ceramicswere prepared by a conventional solid-state method. Effect of TiO2 addition amount on the sintering behavior, phase structure,microstructure and microwave dielectric properties of the ceramics was investigated. The results show that the sintering temperatureof ZMZNT ceramics decreases gradually with the increase of additive amount of TiO2. The X-ray diffraction analysis indicates thatZn0.8Mg0.2（Zr,Ti）Nb2O8 solid solution is formed when x=0–0.5. However, the complicated phase transformation occurs and themorphology changes when x=0.6–0.8. The dielectric constant εr of （1–x）Zn0.8Mg0.2ZrNb2O8-xTiO2 ceramics increases gradually withincreasing TiO2 content. The quality factor Q×f decreases while the frequency temperature coefficient τf increases. The optimalmicrowave dielectric properties（i.e., εr=36.7, Q×f=37 432 GHz, τf=7.12×10^-6/℃） of 0.35Zn0.8Mg0.2ZrNb2O8-0.65TiO2 ceramic sinteredat 1 170 ℃ for 4 h when x=0.65 can be obtained.