Effects of Softener and Hardener Co-doping on Properties of PZT Piezoelectric Ceramics

J. Ocean Eng. Technol. 2010;24(6):81-85.

Lee Eon-Jong,Kim Yun-Hae,Lee Byeong-Woo

Department of Marine Equipment Engineering Korea Maritime University,Department of Marine Equipment Engineering Korea Maritime University,Department of Marine Equipment Engineering Korea Maritime University

Softener 및 Hardener 동시 첨가가 PZT 압전세라믹에 미치는 영향

이언종,김윤해,이병우

한국해양대학교 조선기자재공학부,한국해양대학교 조선기자재공학부,한국해양대학교 조선기자재공학부

Keywords: PZT ceramic, Piezoelectrics, Co-doping, Dopants

핵심용어: PZT 세라믹, 압전체, 동시 도우핑, 도우펀츠

Abstract

The effects of co-doping with complex dopants of softeners, $La^{+3}$ and/or $Nb^{+5}$, and a hardener, $Fe^{+3}$, on the microstructural and piezoelectric properties of PZT ceramics with a composition of a rhombohedral-tetragonal morphotropic phase boundary, $PbZr_{0.53}Ti_{0.47}O_3$, were investigated. Unlike single-element doping, the complex doping of both the softener and hardener ions led to various compensation effects for the piezoelectric properties of the PZT ceramics. For 0.5 wt.% $La_2O_3$ softener and/or 0.5 wt.% $Nb_2O_5$ doped compositions, there were apparent hardener doping (compensation) effects for an addition of over 1.0 wt.% $Fe_2O_3$. For the $La_2O_3$ and/or $Nb_2O_5$ doped composition, the co-dopant $Fe_2O_3$ addition led to lower kp and $varepsilon$r, and increased $Q_m$ values. The prepared PZT ceramics modified with complex soft dopants, $La^{+3}$ and $Nb^+$, as well as a hard dopant, $Fe^{+3}$, showed that the piezoelectric properties were stable with the compositional variations, which made it possible to establish piezoelectric performances with higher reliability and reproducibility. The most improved piezoelectric properties of enhanced $Q_m$ with $varepsilon_r$ remaining higher $k_p$, were obtained in the PZT composition complexly doped with $La^{+3}$ and $Fe^{+3}$. From the results obtained in this study, the properties of compositionally modified PZT ceramics can also be tailored over a wider range by changing the dopant compositions to meet the specific requirements for underwater or other applications.