BZT 25纳米粉体的制备及PVDF/BZT 25纳米复合材料的介电性能

Synthesis of BZT 25 Nano-powder and Dielectric Properties of PVDF/BZT 25 Nanocomposites

通过一步水热法制备了BaZr0.25Ti0.75O3纳米粉体,所得纳米颗粒为均一球形,含钡、锆、钛和氧4种元素。对其成分分析表明,制备的纳米颗粒对应BaZr0.25Ti0.75O3。通过溶液铸膜法,将BaZr0.25Ti0.75O3纳米颗粒作为填充剂制备了PVDF/BaZr0.25Ti0.75O3纳米复合材料薄膜,并表征了介电性能。结果表明,随着BaZr0.25Ti0.75O3的含量从0增加至40 wt%时,介电常数从9.6增加至12.7(1 kHz)。薄膜的介电常数和介电损耗随频率的变化均可观察到两个不同的变化阶段。在低频下(<10 kHz),两相界面极化使得介电常数较高,同时空间电荷极化损耗也较大;当频率升高时,材料内部的转向极化和空间电荷极化都减小,使介电常数和介电损耗减小。在高频下(>10 kHz),介电常数延续减小趋势而介电损耗由于基体PVDF玻璃化转变过程而快速增大。此实验涉及无机陶瓷及其纳米复合材料的制备、表征及数据分析,可在本实验基础上开发专业综合实验,培养学生科研的兴趣,同时为学生从事科研或生产打下基础。

BaZr0.25Ti0.75O3 nanoparticles were prepared by a one-step hydrothermal method.The nanoparticles were spherical in shape,containing the elements of barium,zirconium,titanium and oxygen.The composition analysis showed that the as-prepared nanoparticles correspond to BaZr0.25Ti0.75O3.PVDF/BaZr0.25Ti0.75O3 nanocomposite films were prepared by solution casting with BaZr0.25Ti0.75O3 nanoparticles as fillers,and their dielectric properties were characterized.The results showed that when the content of BaZr0.25Ti0.75O3 increased from 0 to 40 wt%,the dielectric constant increased from 9.6 to 12.7(1 kHz).The dielectric constant and the dielectric loss of the film can be observed in two different stages with the increase of frequency.At low frequency(<10 kHz),the twophase interface polarization gave rise to a larger dielectric constant with a corresponding larger space charge polarization loss.When the frequency increased,the orientation polarization and space charge polarization inside the material decreased,and the dielectric constant and dielectric loss decrease accordingly.At high frequency(>10 kHz),the dielectric constant showed a continuous decrease and the dielectric loss increased rapidly due to the glass transition process.The experiments involve the preparation,characterization,and analysis of inorganic ceramic nanoparticles and their nanocomposites,from which a comprehensive experiment could be developed to cultivate students’interest in scientific research and lay a foundation for students to engage in scientific research or production.