A novel process to synthesize high-k ‘Y5V’ nanopowder and ceramics

The present work proposes a simple one-step sol-gel process for the synthesis of high-k (Ba_0.87Sr_0.04Ca_0.09)(Ti_0.86Zr_0.08Sn_0.06)O₃ (BSCTZS) powders and ceramics. Characterization using TG-DTG, XRD, SEM and TEM methods reveals that the powders are of nanometer scale and exhibit a cubic perovskite structure. After sintering, cubic BaTiO₃ structure ceramics were obtained. Compared to the traditional method of preparation, the powders and ceramics prepared by the one-step sol-gel process exhibit a high dielectric constant due to narrow grain size distribution, controlled morphology, and high purity. Doped niobium decreases the grain size of BSCTZS ceramics and lowers the Curie temperature. At a Nb concentration of 0.38 mol%, BSCTZS ceramics meet the EIA Y5V specifications and the room temperature (25 °C) permittivity is greater than 16,000. The BSCTZS nanopowders prepared through the process with uniformity component will increase the volumetric efficiency of multi-layer ceramic capacitors by decreasing the dielectric layer thickness. Most importantly, this new approach greatly simplifies the preparation processes.