铌欠缺对PZN基陶瓷微观结构和介电性能的影响

使用化学混合法制备了PZN基陶瓷 ,研究了铌离子欠缺对其相组成、微观结构和介电性能的影响。随着铌离子欠缺量的增加 ,预烧粉体中的焦绿石相含量大幅度增加 ;但是微量铌离子欠缺对烧结后陶瓷的相组成没有什么影响 ,甚至当铌欠缺量达到 2 %时 ,陶瓷仍然为 10 0 %的钙钛矿结构。随着铌欠缺的增加 ,晶粒尺寸增大 ,但是陶瓷仍具有良好的成瓷性。铌欠缺使介电常数减小 ,但是对介电损耗影响很小 ;介电常数减小的原因归结为“有效有序微区”尺寸的减小和铁电活性的铌离子浓度的降低

Effect of Nb5+ Deficiency on the Microstrucutre and Dielectric Properties of PZN-Based Relaxor Ceramics

The Pb(Zn 1/3 Nb 2/3 )O 3 based ceramics was prepared by chemical mixture method and the effect of B site Nb 5+ deficiency on phase contents, micro structure and dielectric properties was investigated. With the increase of Nb 5+ deficiency, pyrochlore phase content of the calcined powders increased greatly, while it hardly affected the phase content of the sintered ceramics. Even when the Nb 5+ deficiency reached 2% mol, the sintered ceramics still are 100% perovskite phase. With the increase of Nb 5+ deficiency,the grain size increased. All the specimens are very dense. The results also demonstrated that Nb 5+ deficiency resulted in the decrease of dielectric properties, however, Nb 5+ deficiency only affected dielectric loss slightly. The decrease of dielectric properties resulted from the decrease of effective ordered micro regions size and concentration of ferroelectric active Nb 5+ cations.