Molten-salt synthesis of tetragonal micron-sized barium titanate from a peroxo-hydroxide precursor

- The Ba-Ti-precursor was transformed to BaTiO3 at 1080 °C with Ba/Ti ratio of unity.
- BaTiO3 with different morphologies were formed depending on the heating profile.
- The salt type and concentration influenced the habit-plane growth of BaTiO3.
- Cube-shaped BaTiO3 was formed in NaCl-KCl with either {0 0 1} or {1 0 1} habit-planes.
- Hexagonal-shaped BaTiO3 was synthesized in Na2SO4-K2SO4 with {1 1 1} habit-planes.

Barium titanate (BaTiO3) was produced from an barium-titanate-peroxo-hydroxide precursor material in NaCl-KCl and Na2SO4-K2SO4 salt mixtures or fluxes at temperatures up to 1080 °C via the molten-salt synthesis (MSS) method. Beside the different salt mixtures several other parameters were studied to determine the effect on the particle morphology. A relatively fast heating rate and a relatively high salt to precursor ratio resulted in a highly faceted morphology. The effect of the salt flux was clearly seen in the morphology of BaTiO3 obtained by MSS at 1080 °C. Cube-shaped particles were observed for the chloride-flux-grown BaTiO3 while hexagonal-shaped flat particles were observed for the sulfate-flux-grown BaTiO3. BaTiO3 particles produced in the chloride-flux were either {1 0 1} or {0 0 1} faceted. The hexagonal surface of the sulfate-flux-grown BaTiO3 was {1 1 1} faceted.

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