低温水热合成钛酸钡纳米管阵列薄膜及性能研究

摘要

Nanotube patterned barium titanate thin films were prepared via hydrothermal method using titania nanotube arrays as a template. It was discussed that hydrothermal temperature,reaction time,the concentration of alkali effected on morphology of the samples. Crystal and micro-morphology were observed by X-ray diffraction and scanning electron microscope; thermal properties and dielectric behaviors of materials were characterized by thermogravimetry and differential scanning calorimeter and broadband dielectric spectrometer. The results demonstrated that single-phase structure of nanotube patterned barium titanate thin films could be obtained with the temperature as low as 100℃ after reacting 6h. The longer of reaction time and the higher temperature were helpful to promote the dielectric constant of the samples. Diffusion rates of Ba2+ ions insert into the template was restrained while the growth rates of particles located at the surface of nanotubes were enhanced with the addition of mineralizer KOH. The phenomena of structural transition and phase transition for nanotube patterned barium titanate thin films present at the temperature of 700-1100℃ and 1280℃,respectively.%以二氧化钛纳米管阵列为模版,用水热法合成了钛酸钡纳米管阵列薄膜.讨论了水热温度、水热时间、碱的浓度对其生长形貌的影响.用X射线衍射仪、扫描电子显微镜表征了其晶体结构及微观形貌;用热重-差示扫描量热仪测定了材料的热学性能;用宽频介电阻抗谱仪测试了样品的介电性能.结果表明,在低至100℃水热温度下反应6h即可制得单一相的钛酸钡纳米管阵列薄膜.水热时间的延长和较高的水热反应温度有助于提高样品的介电常数.氢氧化钾的加入抑制了钡离子向纳米管阵列中扩散而促使表面颗粒的结晶长大.纳米管的结构转变温度在700-1100℃之间,至1280℃左右时发生相变转变.