Structure study of Bi_4Ti_3O_(12) produced via mechanochemically assisted synthesis

摘要

Nanosized bismuth titanate was prepared via high-energy ball milling process through mechanically assisted synthesis directly from their oxide mixture of Bi_2O_3 and TiO_2- Only Bi_4Ti_3O_(12) phase was formed after 3 h of milling time. The excess of 3 wt% Bi_2O_3 added in the initial mixture before milling does not improve significantly the formation of Bi_4Ti_3O_(12) phase comparing to stoichiometric mixture. The formed phase was amorphized independently of the milling time. The Rietveld analysis was adopted to determine the crystal structure symmetry, amount of amorphous phase, crystallite size and microstrains. With increasing the milling time from 3 to 12 h, the particle size of formed Bi_4Ti_3O_(12) did not reduced significantly. That was confirmed by SEM and TEM analysis. The particle size was less than 20 nm and show strong tendency to agglomeration. The electron diffraction pattern indicates that Bi_4Ti_3O_(12) crystalline powder is embedded in an amorphous phase of bismuth titanate. Phase composition and atom ratio in BIT ceramics were determined by X-ray diffraction and EDS analysis.