Low Temperature Fabrication of Dense Calcium Titanate Ceramics via Combustion Technique

In this work, dense calcium titanate ferroelectric ceramics were successfully synthesized using the combustion technique. Urea, glycine and the mixture of urea-glycine were selected as fuels and added to the mixed powders to accelerate the chemical reaction of raw materials. The mixtures were calcined and sintered from 600 to1150°C and 1150 to 1450°C, respectively. The effects of firing temperatures on the phase formation, crystal structure, microstructure, density and dielectric properties of the prepared samples were investigated. The X-ray diffraction patterns exhibited a pure perovskite structure which was identified for the glycine and urea-glycine mixed samples calcined at 1000°C for 2 h. The calcined powders exhibited an irregular shape and a wide range of particle size distribution at a low calcination temperature. By increasing the calcination temperature, the average particle size tended to increase and the samples expressed a more spherical shape which decreased the particle size distribution. The microstructure, density and dielectric properties results demonstrated that the optimum sintering temperature was 1400°C. The ceramic sintered at this temperature showed dielectric constant and loss of 194 and 0.004, respectively.