钙钛矿型Pb基反铁电陶瓷粉的合成、结构表征及电性能

发布时间：2018-06-27 07:33

  本文选题：Pb基反铁电材料 + 溶胶-凝胶法　； 参考：《内蒙古工业大学》2015年硕士论文

【摘要】：制备高功率密度、大容量电容器的关键是寻求一种同时具有能量存储密度、高储能效率(即低能量损耗)及快速存放电行为的材料。Pb基反铁电材料就是这样的相变材料,其在温度、电场及应力的诱导下可以实现反铁电态(AFE)与顺电态(P)和AFE与铁电态(FE)之间的快速转变,呈现出双电滞回线,从而可以实现能量的存储与释放。论文采用溶胶-凝胶技术合成了成分不同、但均具有纯相钙钛矿结构的Pb基反铁电陶瓷粉,并将陶瓷粉烧结成陶瓷。借助差热-热重分析仪(DSC-TG),X射线衍射仪(XRD),扫描电子显微镜(SEM)、拉曼测试仪(Ramam)等对陶瓷粉的组成结构进行了表征,采用介电性能测试仪和铁电性能测试仪对陶瓷的电性能进行了测试。探讨了铅过量、添加剂的种类及含量对Pb基陶瓷粉的结构及微观形貌的影响,获得了合成纯相钙钛矿结构PZ陶瓷粉的最优工艺参数。分析了La3+、Ti4+、La3+和Ti4+的混合掺杂对钙钛矿结构Pb基反铁电陶瓷粉的合成温度、晶粒尺寸、微观形貌及电性能的影响。论文采用溶胶-凝胶法制备了不同铅过量的PZ陶瓷粉。实验发现,制备钙钛矿结构的PZ时,铅的最佳过量值为3%。钙钛矿结构PZ陶瓷粉的最佳合成工艺为:煅烧温度为900℃,保温时间为2h。但实验合成的PZ粉体团聚现象严重。考虑到钙钛矿结构PZ的合成温度太高、且粉体团聚现象严重,论文探讨了DEA和PEG对PZ陶瓷粉的相变温度、晶粒尺寸、颗粒形貌等的影响。实验发现,DEA的添加有助于降低单一钙钛矿结构PZ陶瓷粉的合成温度。在Pb过量3%的PZ陶瓷粉中添加10%的DEA,保温2h时,单一钙钛矿结构PZ陶瓷粉的合成温度从900℃降至580℃。添加10%的PEG,PZ陶瓷粉团聚的颗粒分散效果明显。元素掺杂的结果表明,添加La3+、Ti4+后,晶格畸变致使钙钛矿结构的Pb基反铁电材料的晶粒细化,合成温度降低。PLZ陶瓷粉的合成温度为540℃,晶粒尺寸的理论计算值为35.47nm。PZT陶瓷粉的合成温度为600℃,晶粒尺寸的理论计算值为47.50nm。PLZT陶瓷粉的合成温度为580℃,晶粒尺寸的理论计算值为45.43nm。Ramam谱的测试结果表明,室温下,钙钛矿结构PZ的相结构为反铁电正交相,PLZ的相结构为反铁电四方相,PZT的相结构为反铁电正交相,PLZT的相结构为反铁电四方相。电性能的测试结果表明,PZ陶瓷的居里温度TC为226℃;介电常数ε为2264;场致开关场强EA-F=13.4 KV/cm,EF-A=10.2 KV/cm;饱和极化PS=11.28 UC/cm2。PLZ陶瓷的TC为151℃;介电常数ε为3489;场致开关场强EA-F=9.9 KV/cm,EF-A=6.6KV/cm;饱和极化PS=12.26 UC/cm2。PZT陶瓷的TC为230℃;ε为2641,场致开关场强EA-F=12.1 KV/cm,EF-A=7.4KV/cm;PS=19.41 UC/cm2。PLZT的TC降低至148℃;介电常数ε为3196;场致开关场强EA-F=7.4 KV/cm,EF-A=3.8KV/cm;饱和极化PS=22.49UC/cm2。
[Abstract]:The key to fabricating high power density and large capacity capacitors is to find a material with high energy storage density, high energy storage efficiency (I. E. low energy loss) and fast storage behavior. Pb-based antiferroelectric materials are such phase change materials. Under the inducement of temperature, electric field and stress, the antiferroelectric state (AFE) and the paraelectric state (P) and the AFE and the ferroelectric state (FE) can be transformed rapidly, showing a double hysteresis loop, so that the energy can be stored and released. Pb-based antiferroelectric powders with pure phase perovskite structure were synthesized by sol-gel technique and sintered into ceramics. The structure of ceramic powder was characterized by differential thermogravimetric analyzer (DSC-TG) X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman tester (Ramam). The effects of excessive lead and the kinds and contents of additives on the microstructure and microstructure of Pb-based ceramic powders were discussed. The optimum technological parameters for the synthesis of PZ ceramic powders with pure phase perovskite structure were obtained. The effects of mixed doping of La _ 3 and Ti _ 4 on the synthesis temperature, grain size, microstructure and electrical properties of perovskite Pb-based antiferroelectric ceramic powders were analyzed. In this paper, PZ ceramic powder with different lead overdose was prepared by sol-gel method. It is found that the optimum excess value of lead is 3 when PZ with perovskite structure is prepared. The optimum synthesis process of perovskite PZ ceramic powder is as follows: calcination temperature is 900 鈩，

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