Preparation of Ce-Doped (Ba0.87Sr0.04Ca0.09)(Ti0.90Zr0.04Sn0.06)O3 Nano-Crystalline Powders and Ceramics Using the Sol-Gel Method, and their Dielectric Properties

We prepared Ce-doped (Ba0.87Sr0.04Ca0.09)(Ti0.90Zr0.04Sn0.06)O3 (BSCTZS) powders and ceramics using the solgel process. The samples were characterized by means of thermogravimetric, Fourier-transform infrared, X-ray diffraction, and transmission and scanning electron microscope analysis. We also determined the dielectric properties of the ceramics. The results indicated that the SrZrO3 cubic perovskite phase first appeared at a calcining temperature of 600 °C, and facilitated formation of the BaTiO3-based solid solution. The as-synthesized powders calcined at 900 °C for 2 h had a nanometer-scale grain size, with the grains mainly composed of the cubic BaTiO3 phase. After sintering, the ceramics consisted entirely of the cubic BaTiO3 phase. The average grain size and the relative density decreased as the Ce concentration increased. Moreover, the maximum dielectric constant (εmax) decreased and the Curie temperature (Tm) shifted to a lower temperature. Furthermore, the Ce-doped BSCTZS ceramics had a relatively high dielectric constant over a wide temperature range. When the Ce concentration was 0.15 mol%, the BSCTZS ceramics met the Electronic Industries Alliance (EIA) Y5V specifications and the εr (25 °C) was higher than 7500. These merits of the BSCTZS nanopowders and ceramics prepared using the sol-gel method indicate that they will permit a significant reduction in the thickness of multilayer ceramic capacitors and will help meet the current demand for device miniaturization in the electronics industry.