Li_2CO_3掺杂0.98(K_(0.5)Na_(0.5))NbO_3-0.02AETiO_3陶瓷的介电与压电性能

Electrical Properties of 0.98(K_(0.5)Na_(0.5))NbO_3-0.02AETiO_3 piezoceramics doped with Li_2CO_3

采用常规电子陶瓷工艺,制备了1.0%Li2CO3掺杂的0.98(K0.5Na0.5)NbO3-0.02AETiO3(AE=Mg、Ca、Sr和Ba)陶瓷(NKN-AET-Li).X射线衍射图谱(X-raydiffraction:XRD)显示所有样品均为钙钛矿结构,其中NKN-CaT-Li和NKN-SrT-Li陶瓷在室温下为正交-四方共存相,同时具有高的相对密度(>96%);Li2CO3的掺杂提高了NKN-AET-Li陶瓷的居里温度(Tc≥400℃),并明显降低了其正交-四方相变温度To-t;NKN-CaT-Li和NKN-SrT-Li陶瓷室温下具有比较高的压电性能(d33=197pC/N,243pC/N;kp=0.32,0.34),并且其介电及压电性能在50～200℃温度范围内均表现出优良的热稳定性.

The lead-free piezoceramics ceramics 0.98（K0.5Na0.5）NbO3-0.02AETiO3（AE=Mg,Ca,Sr and Ba）doped with 1.0 wt.% Li2CO3（NKN-AET-Li）are prepared by the conventional solid-state reaction method.The X-ray diffraction（XRD）spectra show that the samples possess perovskite structure.NKN-CaT-Li and NKN-SrT-Li ceramics are coexistence of orthorhombic and tetragonal phases with a high relative density（〉 96%）at room temperature.Addition of Li2CO3 obviously increases the Curie temperature（Tc≥ 400 ℃）and decreases the orthorhombic-tetragonal polymorphic phase transition temperature（To-t）for all NKN-AET-Li systems.At room temperature,NKN-CaT-Li ceramics（d33=197 pC/N,kp=0.32）and NKN-SrT-Li ceramics（d33=243 pC/N,kp=0.34）obtain a good piezoelectric properties.Dielectric and piezoelectric properties of NKN-CaT-Li and NKN-SrT-Li remain stable within a temperature range from 50 ℃ to 200 ℃.