Dense and fine-grained barium titanate prepared by spark plasma sintering

Dense and fine-grained barium titanate were successfully sintered by spark plasma sintering at 900 - 1100 °C for 10 minutes under an applied pressure of 30 MPa. The effect of temperature on the densification and microstructure were examined. The relative density of 96.8% was achieved at sintering temperature 1000 °C, and almost fully dense barium titanate was obtained at 1100 °C. In contrast, the relative density of barium titanate prepared by conventional sintering at 1200 °C for 2 h was only 80.1%. These results indicated the effectiveness of spark plasma sintering for fabrication of dense barium titanate. Another characteristic of barium titanate sintered by spark plasma sintering was fine-grained microstructure, as observed at sintering temperature 900 and 1000 °C. In addition, there was crystal structural transformation from cubic to tetragonal after sintering. XRD analysis revealed the cubic structure of as-received powder was changed to tetragonal structure after sintering at 1100 °C. The tetragonality (c/a) of sintered barium titanate was 1.0068, 1.0072 and 1.0088 for sintering temperature of 900, 1000 and 1100 °C, respectively.