A STUDY OF FERROELECTRIC PROPERTIES OF BI4TI3O12 CERAMICS PREPARED FROM CHEMICALLY DERIVED POWDERS

The coprecipitation method was used for the preparation of chemical powders as the starting material in the processing of bismuth titanate ceramics. The proposed procedure is based on the hydrolysis of titanium (III) or titanium (IV) chloride in an aqueous solution of bismuth nitrate. Bismuth titanate ceramic was obtained by reaction sintering of annealed powders. The formation of Bi4Ti3O12 in the sintered samples was confirmed by X-ray diffraction analysis. When the titanium was introduced as TiCl3 an essentially single phase product with ratio Bi2O3/TiO2 = 2:3 was obtained. In the ceramic derived from TiCl4 as starting reagent, an additional phase containing Bi2Ti4O11 (Bi2O3/TiO2 = 1:4) was found. The values of dielectric permittivity derived from the capacity measurements, epsilon(A) = 114, epsilon(B) = 107, were in good agreement with values calculated by means of the Shulgasser model: epsilon(A,calc) = 116.4, epsilon(B,calc.) = 103.4. The hysteresis loops and derived values of coercive field, spontaneous and remanent polarization, indicates the ferroelectric behavior of the obtained ceramic material.