Correlation between the calcination and sintering temperature on phase formation, microstructure and dielectric properties of SrTiO3 ceramics

Abstract

The aim of this work is to investigate the effect of calcination temperature (600, 700 and 800°C) and sintering temperature (1000, 1050 and 1100°C) on pure phase formation, microstructure and dielectric properties of perovskite SrTiO3 (ST) ceramics. The results show that the calcination conditions at 600°C for 6h, are sufficient to obtain this phase. Furthermore, lattice parameter (a) tends to increase with increasing calcinations temperature. The Raman spectroscopy characterization indicates the presence in the calcination spectrum at 600°C of extra-modes located around 113 and 617 cm-1. The optical absorption edge of SrTiO3 was explored in the temperature from 200 to 1000°C. The results suggest that the band gap energy is increasing with temperature. On the other hand, the results found show that the average grain size of the sintered ST at 1100°C is the order of 12µm which is respectively larger than that at 1000 (~ 3.2µm) and at 1050°C (~ 6.4µm). The dielectric study shows that samples sintered at 1100°C have smaller and stable dielectric losses as a function of frequency.