【作者】 程达明；

【导师】 李敬锋；

【作者基本信息】 清华大学 ， 材料科学与工程， 2005， 硕士

【摘要】 铁电体陶瓷镧改性锆钛酸铅(PLZT)具有反常光生伏打效应。PLZT同时又是较好的压电陶瓷,当反常光生伏打效应与逆压电效应耦合,就会产生光致伸缩效应。PLZT陶瓷由于具有该特殊性能,在光控无线驱动以及微感应等方面有着广泛的应用前景。本文总结了目前在PLZT陶瓷制备、性能、应用等方面的研究成果。描述了了PLZT陶瓷体系在铁电、压电、光电等方面的性能特点。讨论了各种因素对该体系材料性能的影响。首先,为了确定成分对PLZT陶瓷的压电、铁电、光电等性能的影响,本研究对具有相同晶粒大小、不同成分含量的PLZT陶瓷的各方面性能进行了比较,从而寻找到了具有最佳本征性能的成分。在本研究中,利用陶瓷烧结理论中的晶粒生长公式,计算得到不同的烧结制度,从而使所研究的11个成分点的PLZT陶瓷的晶粒大小控制在0.7~0.8μm范围内。在此基础上,测定了这些不同成分PLZT陶瓷的性能,发现在相同晶粒大小下,PLZT 4/52/48同时具有最大光电流和最大光生电动势。本研究通过氧化物混合煅烧和机械合金化两种方法合成了PLZT陶瓷。运用不同的球磨设备来合成PLZT陶瓷,对机械合金化方法的合成机制以及最佳合成条件控制进行了深入研究。经过滚动式、行星式球磨机研磨的粉末未得到预期的钙钛矿结构;经过新型多维摆动式球磨机研磨的粉末,在XRD中显示出钙钛矿结构。本研究中,对PLZT/PZT光驱动双压电晶片进行了研究,运用浸蘸法在PZT基板上制备了厚度约为40μm的PLZT厚膜。在最佳工艺条件下制备得到的PLZT厚膜与PZT基板结合紧密,具有良好的微观形貌。更多还原

【Abstract】 Anomalous photovoltaic (APV) effect has been detected in ferroelectriclanthanum-modified lead zirconate titanate (PLZT) ceramics, which also hasgood piezoelectric properties as well. The combination of the two propertiesin PLZT generates photostrictive effect, which has drawn broad attention inthe application in photo-driven and wireless actuators.In this study, the state of arts in the synthesis, the performance and theapplication development of PLZT ceramics has been summarized. Thepiezoelectric, ferroelectric and the photovoltaic properties of PLZT ceramicshave been systematically described.In order to determine the intrinsic compositional effect on the ferroelectric,piezoelectric and photostrictive properties of PLZT, the grain size of PLZTceramics with different compositions were fixed, and the properties abovewere investigated. The ceramic sintering theory of ceramic has been employedto fabricate PLZT ceramics with different compositions but the same grainsize. The grain sizes of PLZT samples with 11 different compositions havebeen controlled within 0.7~0.8μm. With the grain sizes in that range, PLZT4/52/48 demonstrated both maximum photocurrent and photovoltage.In this study, oxide-mixing and mechanical alloying methods have beenused to synthesize PLZT ceramics. To understand the mechanism ofmechanical alloying method, PLZT synthesis has been conducted on differentball milling devices. Although phase transformation of the as-given powdersoccurred, the perovskite structure of PLZT ceramics has not been obtained inthe powder milled by the tumbling mill (90rpm) and the planetary mill(300rpm). Multi-dimensional vibration mill produced PLZT solid solutionpowder with perovskite structure, and the grain-size was significantly reducedas a result of the high kinetic energy of the mill.One of the important applications of PLZT, the photo-driven PLZT/PZTbimorph cantilever has been studied. Dip-coating method has been used todeposit PLZT thick film about 40μm in thickness on the surface of PZTsubstrate. The PLZT thick film obtained under the optimized experimentperimeters has good binding with PZT substrate and demonstrates welldeveloped microstructure.更多还原