纳米晶钛酸钡的介电性能

Dielectric Properties of Nanocrystalline BaTiO_3

采用硬脂酸凝胶法制备了纳米晶BaTiO3,用差热热重分析、红外光谱分析、X射线衍射分析等手段对产物的形成过程、晶型、粒径进行了分析.通过对材料介电性能的研究发现,纳米材料的静态介电常数远大于常规材料的介电常数,随着粒径的减小,纳米材料的介电常数先增大而后有所降低.随着环境湿度的升高,纳米晶材料的介电常数逐渐增大,在高湿度条件下,其介电常数与湿度成线性关系.

Nanocrystalline BaTiO3 is prepared using a stearic acid gel method. The synthesis process, crystalline structure and grain sizes of nanocrystal are investigated by differential thermal analysis, thermogravimetric analysis, infrared spectra and X-ray powder diffraction. The experimental results of dielectric properties of nanocrystal indicate that the dielectric constant epsilon of nanocrystal is much larger than that of bulk materials. With reducing of grain size, the epsilon of nanocrystalline material increases first, then it falls to smaller value. With the increment of relative humidity, the epsilon grows up. The relationship between epsilon and humidity becomes linear with high enough humidity.