PMN-PFN铁电陶瓷低温烧结技术研究

Pb(Mg1/3Nb2/3)O3(PMN)是一种典型的弛豫铁电体,它具有很大的介电常数,较小的介电损耗,良好的压电稳定性和电致伸缩效应,在叠层电容器、致动器等方面有重要的应用。PMN可以方便地与Pb(Fe1/2Nb1/2)O3(PFN)形成固溶体以移动介电常数峰值温度(Tm)。本文使用Swartz和Shrout提出的两步法,研究了基体掺杂不同物质对0.9PMN-0.1PFN和0.75PMN-0.25PFN二元体系的烧结性能及介电性能的影响。经研究发现:添加BiFeO3、Li2CO3、MnO2,都能使烧结温度降低。其中,当在0.9PMN-0.1PFN中掺入5wt%的Li2CO3时,介电常数为18120,大于纯组分的0.9PMN-0.1PFN的介电常数,当掺入BiFeO3和MnO2时,都使介电性能恶化。对不同掺杂对性能的影响进行了解释。

A STUDY OF LOW TEMPERATURE SINTERING TECHNOLOGY OF PMN-PFN FERROELECTRIC CERAMICS

Lead magnesium niobate, Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) is a well-known typical ferroelectric relaxor, with very high dielectric constant, low dielectric loss, excellent piezoelectric stability and electrostrictive effect. PMN can easily be formed into solid solutions with lead iron niobate, Pb(Fe1 /2Nb 1/2)O 3 (PFN) to shift its temperature of maximum dielectric constant (Tm). These properties can be manipulated to serve many functions, such as applications in multilayer ceramic capacitors (MLCCs), actuators, micropositioners and so on. Sintering properties and dielectric properties were studied by adding a small amount of different dopants into 0.9PMN-0.1PFN and 0.75PMN-0.25PFN ceramics using the conventional two-step processing which was first proposed by Swartz and Shrout. It has shown that when doped with BiFeO3 or Li 2CO 3 or MnO2, the sintering temperature can be decreased. Most of all, when doped with 5wt% Li 2CO 3, the dielectric constant of this material is 18120 (1 kHz), which is higher than that of pure 0.9PMN-0.1PFN. When doped with BiFeO3 and MnO 2, on the contrary, the properties were deteriorated. The possible mechanism was proposed.