The BCST ceramics possess pure tetragonal
phase, when x = 0.04. Therefore, it can be suggested that
orthorhombic phase and tetragonal phase coexist in the composition
range of 0.02 < x < 0.04 for the BCST ceramics at room
temperature. The changing of the lattice parameter with increasing
of Sn content in BCST ceramics confirms the discussion
above. Lattice parameters calculated from the diffraction data
are presented in Table 1. Fig. 2 shows SEM micrographs of the
BCST ceramics at x = 0.01, 0.02, 0.03 and 0.04, respectively.
The microstructure of BCST ceramics at x = 0.01 is inhomogeneous
and some pores exist in the grain boundary