Preparation of the Oriented Polycrystalline BaTi2O5 Ferroelectric Ceramics

The dense and oriented BaTi2O5 (BT2) in a single phase was successfully obtained by an arc melting process on a water-cooled copper plate using BaCO3 and TiO2 as starting materials and B2O3 as an additive. XRD pattern of BT2 showed a preferred orientation of (020). The microstructure of BT2 was examined to show a needle-like shape and the BT2 grains were 3~15 µm in diameters and 22~110 µm in lengths. Though B2O3 was effective to prepare dense BT2, it, disadvantageously, tended to decrease the permittivity of BT2. The discrepancy of the peak frequencies between Z″ and M″ could be ascribed to the existence of structural defects and occurrence of the second phase. The maximum permittivity was 863 when the frequency (f) and the Curie temperature (Tc) were 100 kHz and 465°C, respectively.