Preparation and characterizatioii of BaTiO3 powders and ceramics by sol-gel process using hexanoic and hexanedioic acid as surfactant

The. BaTiO3 xerogels, powders and ceramics were prepared through the sol-gel process using hexanedioic acid as surfactant. The xerogels, powders and ceramics were characterized by methods of thermal analysis, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, and transmission electron microscope. The dielectric properties Of the Ceramics Were also measured. The results indicated that the powders calcined at 900 degrees C for 2 h were pure BaTiO3 phase partly consisted of the tetrahedron BaTiO3. The powders were nanometer scale particles. After sintering, the ceramics mainly consisted of the tetrahedron BaTiO3 phase. Compared with the powders prepared using hexanoic acid as surfactant, the particle size of the powders prepared using hexanedioic acid obviously increased, and as well as the grain size, the relative density and the whole permittivity of the ceramics increased. Furthermore, the forming process of the powders with better dispersibility and the influence of the carboxyl number on the particle size of the powders can be explained using the organic acid micro-capsules model. Relatively, the ceramic prepared using hexanedioic acid as the surfactant had higher relative density (96-6%), room temperature permittivity (3089) and lower dielectric loss (0.015). (C) 2008 Elsevier B.V. All rights reserved.