含Pt金属芯压电陶瓷纤维的微观结构和电学性能

以传统固相法制备的0．55Pb（Ni1/3Nb2／3）O3-0．45Pb（Zr0.3Ti0.7）03（PNN-PZT）压电陶瓷粉体为原料，采用挤压成型工艺制备含Pt金属芯压电陶瓷纤维。以PbTi03作为保护粉体，对纤维坯体进行1200℃不同时间（0．5、1．0h和2．0h）的烧结处理。利用X射线衍射仪、扫描电子显微镜、阻抗分析仪和铁电分析仪等研究了烧结时间对纤维微观结构、压电性能和铁电性能的影响。结果表明：在烧结时间范围内制备的压电陶瓷纤维为单一钙钛矿结构，未发现焦绿石相或其他杂相；随烧结时间增加，陶瓷纤维晶粒尺寸增大，压电和铁电性能明显提高。在1200℃保温2．0h制备的压电陶瓷纤维电学性能较好，压电常数（西1）、相对介电常数（曲、介电损耗（tanδ）和矫顽场（＆）分别为-145pC／N、3313、2．6％和0．27kV／mm。介电温谱结果表明：该陶瓷纤维的特征Curie温度为125℃，峰值相对介电常数为8093。

Microstructure and Electrical Property of Piezoelectric Ceramic Fibers with Pt Metal Core

Raw materials of 0.55Pb(Ni1/3Nb2/3)O3–0.45Pb(Zr0.3Ti0.7)O3(PNN–PZT) ceramics were prepared by a traditional solid-state sintering method,and then piezoelectric ceramic fibers with platinum(Pt) metal core were successfully fabricated by an extruding technique.The green fibers were sintered at 1 200 ℃ for different time(0.5,1.0 h and 2.0 h) using PbTiO3 as protection powder.The obtained fibers were characterized by X-ray diffractometer,scanning electron microscope,precise impedance analyzer,and ferroelec-tric analyzer system.The influences of sintering time on microstructure,piezoelectric and dielectric properties of the obtained fibers were investigated.Results showed that all samples prepared in sintering time range exhibited a single perovskite structure and no detectable traces of the pyrochlore or other impurities were identified.With increasing sintering time,the grain size increased slightly,and the piezoelectric and ferroelectric properties were also obviously improved.The piezoelectric constant(d31),relative dielectric constant(εr),dielectric loss(tan δ) and coercive field(Ec) were –145 pC/N,3 313,2.6%,and 0.27 kV/mm,respectively,for the sam-ples sintered at 1 200 ℃ for 2.0 h.The temperature dependence of the dielectric constant showed that the maximum value of relative dielectric constant was 8 093 at the characteristic Curie temperature of 125 ℃.