resumo
The hydrothermal synthesis of barium titanate particles by reaction of titanate layered nanotubes and barium hydroxide in aqueous solution at 90, 110, and 200 degrees C from I to 24 h has been studied. Anisotropic growth of barium titanate particles was observed when the synthesis temperature was 90 degrees C resulting in the formation of pseudo-cubic BaTiO3 single-crystal particles with a "wild"-type dendritic shape. Synthesis at 110 degrees C led to the formation of round-shaped, pseudo-cubic, and tetragonal BaTiO3 particles. At 200 degrees C, single-crystal barium titanate "seaweed"- type dendritic particles with predominantly tetragonal structure were obtained. This study demonstrates that the anisotropic growth of barium titanate crystals can be controlled by manipulating the temperature and time of reaction and highlights the influence of the synthesis parameters on the anisotropic growth of BaTiO3 crystals under hydrothermal conditions when using layered titanates with nanotube morphology as Ti precursor.
palavras-chave
BARIUM-TITANATE NANOWIRES; SOFT CHEMICAL-PROCESS; NANOCRYSTALLINE BATIO3; STRONTIUM-TITANATE; FINE POWDERS; PARTICLES; KINETICS
categoria
Chemistry; Crystallography; Materials Science
autores
Maxim, F; Ferreira, P; Vilarinho, PM; Reaney, I
nossos autores
Paula Celeste da Silva Ferreira
Investigador Coordenador
Paula Maria Lousada Silveirinha Vilarinho
Vice-Diretoragradecimentos
The authors acknowledge FCT, FEDER and European Network of Excellence FAME, under Contract FP6-500159-1. F.M. is thankful to FCT for the fellowship SFRH/BD/23375/2005.