Influence of ball milling parameters on the particle size of barium titanate nanocrystalline powders

Barium titanate (BaTiO3 or BT) powder was synthesized from BaCO3–TiO2 reaction at high temperature. This powder was then used to produce BT nanocrystalline powders using high-energy ball milling under different milling conditions. All the milled powders were examined by XRD and TEM. The particle sizes calculated by the Sherrer formula from the XRD patterns agree with the results of TEM images. The particle size was investigated by varying (i) the speed of the mill from 200 to 400 rpm with regular interval of 50 rpm, fixing the milling time at 30 h, and (ii) the milling time from 15 to 40 h, at a fixed speed of 300 rpm. The increase in milling speed results in a gradual reduction in particle size till it finally reaches a saturation value of about 18 nm. However, with increasing milling time, the particle size first decreases, attains a minimum value of about 16 nm and then increases. The involved mechanisms of the observed results are discussed in the present paper.