Effect of calcination time on the microstructure and dielectric properties of CaCu3Ti4O12 using enhanced microwave processing

Abstract

Calcium copper titanate, CaCu3Ti4O12 (CCTO) is an electroceramic that belongs to the perovskite structure family. CCTO has received much attention due to its very high dielectric constant. However, it has a high dielectric loss that undesirable in the electronic application. Researchers have studied many methods to overcome the problem thus in this study, the influence of microwave radiation during calcination to the electrical properties was investigated. The synthesis process of CCTO samples was carried out using a solid-state reaction route. The calcination process was conducted at 500℃ with different calcination time using microwave furnace operated at the frequency of 2.45 GHz and assisted with enhanced silicon carbide (SiC)-based susceptor. XRD pattern revealed that the formation of cubic perovskite CCTO was obtained partially after calcination at 500℃ for more than 5 hours, but the single-phase CCTO was not completely formed at this temperature. The SEM microstructure showed grain growth and reduction in porosity and grain boundaries of the pellets with the increase of calcination time. Dielectric properties also increase with the increase of calcination time. The dielectric constants for the CCTO pellets were found to vary from 200 to 2900 in the frequency range of 1 MHz to 10 GHz.