Microwave assisted synthesis, sintering of lead-free ferroelectric CaBi4Ti4O15 ceramics

Abstract

Calcium Bismuth Titanate (CBTi) ceramics were prepared by solid state reaction method and sintered in microwave heating process from 1050°C – 1200°C for 20 min. The formation of single phase with Orthorhombic structure was verified by X-Ray diffraction and Raman spectroscopy. The orthorhombic distortion present in the CBTi ceramic sintered at 1150°C was found to be maximum. The plate like morphology of the surface of the samples is observed in FE-SEM. The dielectric properties were measured at room temperature with Impedance Analyser. The ceramics sintered at 1150°C for 20 min. in microwave furnace show superior dielectric properties than 1200°C in conventional furnace for 2 hrs. The dielectric constants varies from 125-212 at 3KHz and losses are minimum. The presence of large orthorhombic distortion in the CBTi ceramics sintered at 1150°C results in high dielectric constant and low dielectric loss. The observed results indicate the importance of orthorhombic distortion and microwave sintering in enhancing the dielectric properties of a ferroelectric material.