朱彦，李如月，沈圳，杨松，仪鹏，李伟*
材料科学与工程学院，聊城大学，聊城，252000
关键词：BNT；无铅；薄膜；退火；压电
中图分类号：O484.5 文献标识码：A
摘要：(Bi1/2Na1/2)TiO3-(Bi1/2K1/2)TiO3-SrTiO3 (BNT-BKT-ST)三元系压电材料体系在斜方相和弛豫赝立方相共存区域具有极高的电致应变特性，因而备受研究者关注。本研究利用溶胶法在衬底上制备了BNT-BKT-ST无铅压电薄膜，研究了退火温度（800℃～1100℃）对BNT-BKT-ST薄膜结构和压电性能的影响。结果表明：BNT-BKT-ST薄膜均为单一钙钛矿结构，无杂相产生；随着退火温度升高，薄膜表面空隙率降低，晶粒长大，当退火温度达到1100℃时，出现异常长大的条状晶粒；BNT-BKT-ST薄膜的压电性能随退火温度升高逐渐增大，当温度达到1000℃时，电致应变和局部压电常数达到最大值（S=0.38%，d33=220pm/V），之后随温度升高有所降低；薄膜的铁电性能也随退火温度升高逐渐增强，当温度达到1000℃时，剩余极化Pr达到最大值（18 μC/cm2），之后随温度升高剩余极化降低。提高退火温度可以使薄膜晶粒长大，并提高压电性能和铁电性能，但是过高的退火温度可能会生长出异常大的棒晶粒，从而抑制了薄膜的压电性能和铁电性能。
Effects of anneal temperature on the structure and piezoelectrical properties of BNT-BKT-ST thin films
Yan Zhu, Ruyue Li, Zhen Shen, Song Yang, Peng Yi, Wei Li
College of Materials Science and Engineering, Liaocheng University, Liaocheng 252059, China.
Keywords: BNT; Lead free; Thin films; Anneal temperature; Piezoelectric properties
Abstract: The ternary (Bi1/2Na1/2)TiO3-(Bi1/2K1/2)TiO3-SrTiO3 (BNT-BKT-ST) materials are highlighted by several research reviews because the piezoelectric properties are greatly improved at the morphotropic phase boundary (MPB) region. Herein, the structure and piezoelectric properties of the BNT-BKT-ST thin films as a function of anneal temperature were investigated.All the thin films have pure perovskite structure and no second phases could be observed. The grain size increases and the pinholes decrease with the anneal temperature, while abnormal clubbed grains emerge at 1100℃. The piezoelectric properties increase with the anneal temperature to the peaks (S=0.38%, d33=220 pm/V) at 1000℃, and then decrease. The ferroelectric properties increase with the anneal temperature before 1000℃. The Pr value reaches the maximum of 18 μC/cm2 at 1000℃ and decrease with the further increase of anneal temperature. The grain size, piezoelectric and ferroelectric properties are increased with the increase of anneal temperature ( ≤1000℃). However. piezoelectric and ferroelectric properties are reduced with the further increase of anneal temperature ( >1000℃).
Keywords: BNT; Lead free; Thin films; Anneal temperature; Piezoelectric properties