掺杂对准同型相界附近PMN-PT陶瓷介电和铁电性能的影响

DIELECTRIC AND FERROELECTRIC PROPERTIES OF ION-DOPED PMN-PT CERAMICS NEAR MORPHOTROPIC PHASE BOUNDARY

采用氧化物固相反应法制备了A、B位离子掺杂0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3陶瓷,研究了掺杂对陶瓷的相结构、介电和铁电性能等的影响。Sm和La两种A位掺杂离子的引入,均较大幅度的降低了样品的介电常数峰温和声誉极化值,同时材料的最大介电常数也有了不同程度的降低。而随着B位离子Mn掺杂量的增加,使陶瓷样品中钙钛矿相逐渐增加,焦绿石相逐渐降低;而且部分掺杂的Mn离子会进入到晶格的B位,形成第二相;同时随着Mn离子掺杂量的增加,介电峰值逐渐增大,压电性能有所提高,弥散度依次增大。当锰掺杂量为1.5%mol时的压电陶瓷组分,其介电和压电性能各为:ε=2300,kp=0.54,Qm=900,tanδ=0.004,d33=400pC/N,适合于制作大功率压电陶瓷变压器。

A-site and B-site ion-doped 0.67Pb（Mg1/3Nb2/3）O3-0.33PbTiO3 ceramics were prepared by an oxide solid state reaction method. Phase structure, dielectric and ferroelectric properties of the ceramics were studied. The investigation shows that： doping of A-site ions reduces the maximum dielectric constant, peak temperature of dielectric constant and remnant polarization of the ceramics. With the increasing of modifier content of B-site Mn^2＋, the content of pyrochlore phase decreases and the piezoelectric properties get hardened with the increase of Mn composition. Dielectric constant, piezoelectric constant d33 and electro-mechanical quality factor Qm increase, but dielectric loss tanδ decreases with Mn composition when Mn composition is less than 1.5mol%.ε, Kp, Qm, tanδ and d33 of the ceramic doped with 1.5mol% Mn are 2300, 0.54, 900, 0.004 and 400pC/N respectively. The ceramic could be used for the application of high power piezoelectric transformer.