Effect of Ta<sub>2</sub>O<sub>5</sub> on Sintering of BaTiO<sub>3</sub>

Abstract

BaTiO3 ceramics including 0.2mol% Ta2O5, increases its compactness due to the agglomeration during the first sintering period, but the compactness decreases with decreasing the particle size of the starting BaTiO3. The inhomogeneous formation of necks among the particles and the inconsistent growth rate of neck were observed. This seems to result in a wide distribution of the particle size and the size of the pores among the particles. In the middle sintering period the agglomeration will proceed with disappearance of the voids in the cross-linked structure by adhesion among the particles. Eventually the compactness of the ceramics increases, however, the agglomerating region are quite different in size. In the final sintering period the local formations of abnormally grown particles were observed in the agglomerating region. The inhomogeneous mixing of large and small particles has the responsibility to form various pores having many different diameter and results in a decrease of the density. In conclusion the decrease in the density seems to be due inhomogeneous distribution of pore caused by the rapid rearrangement of the fine particles and the irregular formation of the necks among the particles.