Journal of Materials Science, Vol.45, No.10, 2606-2610, 2010
Dielectric Ba(Ti1-x Sn (x) )O-3 (x=0.13) ceramics, sintered by spark plasma and conventional methods
A two-step sintering approach composed of spark-plasma-sintering (SPS) technique at 1000 A degrees C for 1 min and under a uniaxial pressure of 63 MPa followed by conventional sintering at 1400 A degrees C for 3 h is proposed for synthesis of dense Ba(Ti0.87Sn0.13)O-3 ceramics. Starting powders had grain size of about 90 nm and were obtained by co-precipitation. The SPS pellets consist of submicron (300-500 nm) grains. X-ray diffraction analysis of as-prepared Ba(Ti0.87Sn0.13)O-3 ceramic shows the occurrence of cubic and tetragonal phase coexistence for the pellets obtained after SPS processing and the presence of only tetragonal phase in the samples after the second (conventional) sintering. Grain uniformity in the final product is high, with average size of similar to 2 mu m. The apparent densities of the sintered pellets at temperature of 1400 A degrees C were similar to 92% of the theoretical value of Ba(Ti0.87Sn0.13)O-3. The ceramics exhibit a high relative dielectric constant of 6,550 and a dielectric loss (tan delta) = 0.078 at Curie temperature of 63 A degrees C and 10 Hz.