A Novel One-Step Flame Synthesis Method for Tungsten-Doped CCTO

Abstract

An efficient synthesis is used for the first time to prepare CaCu3Ti4-xWxO12 (x = 0.01, 0.03, and 0.05) electroceramics for energy storage capacitors. CaCu3Ti4-xWxO12 ceramics are synthesized via flame synthesis of metal nitrates precursors in nonaqueous solution using cheap, stable, and insoluble solid TiO2 powder. The pathway yielded a CaCu3Ti4O12 (CCTO) phase with the traces of CuO and CaTiO3 sintered at 1050°C for 30 h. The SEM micrograph shows the grains with smooth surfaces associated with cubical appearance and the size range of 1.5-7, 2.0-7.5, and 2.0-8.0 μm for CCTWO01, CCTWO03, and CCTWO05, respectively. The EDX and XPS analyses show the presence of Ca, Cu, Ti, W, and O elements confirming the purity of these ceramics. The complex impedance and modulus (M) spectroscopy show that the dielectric constant (εr) values of the W-doped CCTO were dominantly affected by the electrical properties of the grain boundary, which is also evident from the SEM micrographs. The grain-boundary resistance decreased with increasing tungsten content. The activation energies for the grain boundaries were calculated from the impedance and modulus data using the slope of the ln τ versus 1/T and were found to be in the range 0.62-0.67 eV. © 2015 The American Ceramic Society.