(Pb0.97La0.02)(Zr0.65Sn0.35-xTi x)O3反铁电陶瓷的热膨胀性质

在-100—200℃温度范围内，测量了(Pb_0.97La_0.02)(Zr_{0.65< /sub>Sn0.35-xTix)O3(PZST，0.1≤x≤0.14)反铁电陶 瓷的热膨胀性质.实验结果表明，组分在0.1 ≤x≤0.12的试样室温下为反铁电(AFEt)四方相，热膨胀系数(α)在低温段发生 “弯曲” ，而变温x射线衍射谱(XRD)显示材料保持四方相结构；当Ti含量在0.125≤x≤0.14时，室温 下是铁电三方相(FER)，温度升高时FER→AFEt相变体 积收缩，AFEt→立方顺电(PE c)相变体积增大；变温XRD谱证明了材料相结构随温度的转变过程.用多元复杂 化合物存在 纳米线度组分非均匀的观点解释了热膨胀性质随Ti含量演化的物理机理，并得到了该系统的 温度-Ti(x)含量相图. 关键词： 热膨胀性质 铁电/反铁电相界 反铁电陶瓷 PZST}

Thermal expansion property of (Pb0.97La0.02)(Zr0.65< /sub>Sn0.35-xTix)O3 ceramics

The phase transformation and thermal expansion behaviour of (Pb_0.97La _0.02(Zr_0.65Sn_0.35-xTi_x)O₃ (PZST,0.1≤x≤0.14)antiferroelectric ceramics (AFE_t)have been investigated as functions of temperature and Ti conte nt x.It was found that for the specimens with 0.1≤x≤0.12,the thermal expansion coefficient (α) curve showed an unusual “bending” at the temperature of T,wh ile the specimens remained a tetragonal phase.For 0.125≤x≤0.14,the specimens s howed a ferroelectric rhombohedral phase (FE_R) at room temperature.Wh en heated ,the FE_R phase was changed to an antiferroelectric tetragonal phase ( AFE_t) a nd pareoelectroic cubic phase (PE_c) at temperatures of T_FA and T_c,resp ectively.In addition,T and T_FA increased with the increase of Ti cont ent x , while T_c was decreased.The phases were detected by the XRD pattern at differ ent temperatures.The temperature-Ti content (x) phase diagram of (Pb_{0.97La 0.02)(Zr0.65Sn0.35-xTix)O3 was finally established.The the rmal expansion behaviour of (Pb0.97La0.02)(Zr0.65Sn0.35-xTix)O3 (0.1≤x≤0.14) have been expla ined based upon the nano-size phase s eparation of the PZST complex pervoskite compounds.}