铌酸钾钠（KNN）无铅压电薄膜的制备及其改性研究
发布时间：2018-08-24 21:04
【摘要】：铌酸钾钠(KNN)无铅压电薄膜凭借高居里温度,优良的压电性以及良好的生物相容性,可广泛地应用于驱动器、传感器及致动器等领域。本文采用溶胶凝胶法制备KNN薄膜,探究了热裂解温度和退火温度,离子(Li~+,Mn~(2+))掺杂及引入缓冲层(Nb_2O_5,SiTiO_3)对KNN薄膜结构和性能的影响。主要研究结果如下:热裂解温度过低,薄膜内有机物不完全分解,产生大量孔洞;热解温度过高导致碱金属离子挥发严重,薄膜氧空位增多。退火温度较低,晶粒不完全长大,薄膜结晶性差;退火温度过高,碱金属离子大量挥发。当热裂解温度为400℃,退火温度为600℃时,薄膜性能最优:在1k Hz下,ε_r为712,在200 kV/cm电场下,2P_r和2E_c分别为6.2μC/cm~2、118.6 kV/cm。Li离子主要取代KNN薄膜的A位离子,可以细化晶粒,改善薄膜的结晶性,使薄膜更加致密均匀。当Li离子掺杂量为1.5 mol%时,薄膜结晶性好,电学性能最优:在1 k Hz,ε_r为449.7,在200 kV/cm电场下,2P_r和2E_c分别为10.3μC/cm~2、107.2 kV/cm;Mn离子通过变价降低薄膜中载流子空穴浓度,从而提高薄膜的质量和性能。当Mn离子掺杂量为2 mol%时,KNLN薄膜具有最佳的性能:在1 kHz下,ε_r为875、tanδ为0.030;在200 kV/cm电场下,2P_r为22.5mC/cm~2;2E_c为130 kV/cm。Nb_2O_5缓冲层起到良好的过渡作用,降低了薄膜和衬底的相互扩散,减少了晶格失配引起的界面缺陷。当Nb_2O_5缓冲层为2层时,KNN薄膜的性能最优:在1 k Hz下,ε_r为265,在108.5kV/cm电场下,2P_r为7.8mC/cm~2;2E_c为75.8 kV/cm。SrTi O_3缓冲层能降低薄膜和衬底间的晶格失配,抑制界面非铁电活性层的出现,改善薄膜的质量和性能。当SrTi O_3缓冲层为2层时,KNN薄膜的性能最优:在1 k Hz下,ε_r为446,在200 kV/cm电场下,2P_r为10.8mC/cm~2;2E_c为121 kV/cm。
[Abstract]:Potassium niobate (KNN) lead-free piezoelectric film is widely used in actuators sensors and actuators due to its high Curie temperature excellent piezoelectric properties and good biocompatibility. In this paper, KNN thin films were prepared by sol-gel method. The effects of pyrolysis temperature and annealing temperature, doping of Li~ mn ~ (2) and introducing buffer layer (Nb_2O_5,SiTiO_3) on the structure and properties of KNN thin films were investigated. The main results are as follows: the pyrolysis temperature is too low, the organic matter in the film is not completely decomposed, a large number of pores are produced, and the excessive pyrolysis temperature leads to the evaporation of alkali metal ions and the increase of oxygen vacancies in the films. The annealing temperature is low, the grain is not fully grown, the crystallinity of the film is poor, and the annealing temperature is too high, the alkali metal ions volatilize a lot. When the pyrolysis temperature is 400 鈩，
本文编号：2202034
[Abstract]:Potassium niobate (KNN) lead-free piezoelectric film is widely used in actuators sensors and actuators due to its high Curie temperature excellent piezoelectric properties and good biocompatibility. In this paper, KNN thin films were prepared by sol-gel method. The effects of pyrolysis temperature and annealing temperature, doping of Li~ mn ~ (2) and introducing buffer layer (Nb_2O_5,SiTiO_3) on the structure and properties of KNN thin films were investigated. The main results are as follows: the pyrolysis temperature is too low, the organic matter in the film is not completely decomposed, a large number of pores are produced, and the excessive pyrolysis temperature leads to the evaporation of alkali metal ions and the increase of oxygen vacancies in the films. The annealing temperature is low, the grain is not fully grown, the crystallinity of the film is poor, and the annealing temperature is too high, the alkali metal ions volatilize a lot. When the pyrolysis temperature is 400 鈩，
本文编号：2202034
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