Study On Processing And Property-Composition Relationship Of PLZT Ceramics

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.