非化学计量比铌酸锌微波介电陶瓷的低温烧结行为

Low-Temperature Sintering of Non-stoichiometric Zinc Niobite Microwave Dielectric Ceramics

采用固相烧结工艺制备低损耗、非化学计量比Zn1.01Nb2O6微波介电陶瓷。研究了添加不同量的Li2CO3–B2O3–V2O5(LBV)对Zn1.01Nb2O6陶瓷烧结温度、表面形貌以及微波介电性能的影响。结果表明:LBV作为助烧剂,在陶瓷烧结过程中产生了液相,当添加剂含量大于1.5%(质量分数)时,LBV与基体陶瓷发生了化学反应。液相的产生、副相LiZnNbO4的形成以及V5+的扩散共同改善了陶瓷的烧结行为,使烧结温度由1 175℃低至950℃。LBV加入到基体陶瓷后对微波介电性能影响较小。当LBV添加量为1.0%,并在950℃保温4 h后,Zn1.01Nb2O6陶瓷微波介电性能最优:εr=20.6,Q×f=90 472 GHz,τf=–85.9×10–6℃–1。

Low-loss dielectric non-stoichiometric Zn1.01Nb2O6 ceramics were synthesized by a solid-state technique.The effect of Li2CO3–B2O3–V2O5(LBV)additives on the sintering behavior,surface morphology and microwave dielectric performance was investigated.A liquid phase formes during sintering,and the LBV reacts with a matrix material at the LBV addition content of>1.5%.The LBV addition reduces the sintering temperature from 1 175 to 950℃due to the formation of liquid phase and second phase LiZnNbO4,and the substitution of V5+for Nb5+.The addition of LBV does not induce an apparent degradation in microwave dielectric properties.At 1.0%LBV addition,the ceramic sintered at 950℃for 4 h possesses the optimum microwave dielectric properties(i.e.,εr=20.6,Q×f=90 472 GHz,andτf=–85.9×10–6℃–1).