Solid‐State Synthesis of Ultrafine BaTiO3 Powders from Nanocrystalline BaCO3 and TiO2

Barium titanate has been prepared by solid‐state reaction of nanocrystalline TiO 2 (70 nm) with BaCO 3 of different particle size (650, 140, and 50 nm). The results give evidence of a strong effect of the size of BaCO 3 in the solid‐state synthesis of barium titanate. The use of nanocrystalline BaCO 3 already leads to formation of the single‐phase BaTiO 3 after calcination for 8 h at 800°C. The final powder consists of primary particles of ≈100 nm, has a narrow particle size distribution with d 50 =270 nm, and no agglomerates larger than 800 nm. For the coarser carbonate, 4 h calcination at 1000°C are required and the final powder is much coarser. Solid‐state reaction of nanocrystalline BaCO 3 and TiO 2 represents an alternative to chemical preparation routes for the production of barium titanate ultrafine powders.