钨青铜型结构PBNN压电陶瓷电场-应变特性研究

Characterization of Strain vs Field of PBNN Piezoelectric Ceramic withTungsten Bronze Structure

对钨青铜结构型的压电陶瓷［Pbx（Ba．Sr）1-x］4（Na0．88Li0．12）2Nb10O30，x＝0．64（PBNN）的逆压电效应的应变（S）随电场（E）变化特性进行了研究，研究表明该材料的S-E线性好，滞后小．是一种制备随动型压电微位移器的优良材料．从X射线结构分析和S-E变化关系精细测量分析表明，该材料不存在钙钛矿结构型PZT系压电陶瓷（属赝立方铁电相）中由于，三晶轴在外电场下互换形成的畴的90°转向，仅有畴的180°转向．这是它S-E特性优良的原因．测量表明，其S-E关系在～350V／mm较高场强处斜率呈现～5％的微小突增，认为这是由于它属假正交晶系，在较强外场下轴长几乎相等的a、b轴间互换对应变的贡献所致．

The characterizations of strain S with electric E in converse piezoelectric effect for [Pbx(Ba,Sr)1-x]4 (Nho.88Li0.12)2Nb10O30x=0.64 (PBNN) piezoelectric ceramic with tungsten bronze (T.B.)structure were studied. The excellent micro-displacement properties, such as high linearity, lowhysteresis and high coercive field, were exhibited for PBNN ceramic, which were suitable to prepareservo piezoelectric actuators. According to X-ray distraction structure analysis and measurementresults of the relation of S with E, it was shown that in the PBNN piezoelectric ceramic withT.B. structure only the 180° switch of the domain exists without 90' switch of the domain, whichinherently exists in PZT based piezoelectric ceramics with peroveskite (P.S.) structure. For PBNNceramic the excellent characterization of S with E was due to their no 90' switch of the domain.It is found that by more carefully measuring and analyzing the cllrve of S with E a slight increaseof slope (about 5%) occurs at a higher electric field ~350V/mm, which had been explained frompseudo-orthorhombic crystal structure of PBNN ceramic.