DocumentCode :
3412530
Title :
Preparation of nm-ordered barium titanate fine particles using the 2-step thermal decomposition of barium titanyl oxalate and their dielectric properties
Author :
Wada, S. ; Hoshina, T. ; Kakemoto, H. ; Tsurumi, T.
Author_Institution :
Dept. of Metall. & Ceramics Sci., Tokyo Inst. of Technol., Japan
fYear :
2002
fDate :
28 May-1 June 2002
Firstpage :
263
Lastpage :
266
Abstract :
The new 2-step thermal decomposition method using barium titanyl oxalate (BaTiO(C2O4)2·4H2O) was proposed to obtain impurity-free and defect-free nm-sized barium titanate (BaTiO3) particles. At the 1st step, BaTiO(C2O4)2·4H2O was annealed at 400°C for 1 h in the O2 flow. This product obtained at 400°C was amorphous, but its chemical composition was BaCO3-TiO2. At the 2nd step, the amorphous compound was annealed under vacuum. Finally, the BaTiO3 single crystals with a size of 16.5 nm were prepared around 620°C. Their characterization was done using various methods. As the impurities, the surface adsorbed hydroxyl group (OH) and the surface adsorbed carbonate (CO3-)were detected, but no lattice hydroxyl group was detected using IR. These results suggested that the BaTiO, crystallites have less impurity in their lattice. The relative density of the BaTiO, crystallites was over 98%. Moreover, a new powder dielectric measurement was proposed. This method was composed of two parts; (1) the dielectric measurement using the slurry of the BaTiO3 crystallites with 1-propanol and (2) the simulation using the electrostatic field analysis of the finite element method. When these two kinds of the values becomes to same, the dielectric constant of the BaTiO, crystallites can be determined. Using this powder dielectric measurement, the dielectric constant of the BaTiO3 crystallites with a size of 16.5 nm were determined at almost 400.
Keywords :
barium compounds; ferroelectric materials; finite element analysis; infrared spectra; nanoparticles; particle size; permittivity; pyrolysis; 1 h; 1-propanol; 16.5 nm; 400 degC; 620 degC; BaCO3-TiO2; BaTiO(C2O4)2·4H2O; BaTiO3; BaTiO3 nanoparticles; barium titanyl oxalate; chemical composition; defect-free particles; dielectric constant; dielectric properties; electrostatic field analysis; finite element method; impurity-free particles; lattice hydroxyl group; slurry; surface adsorbed carbonate; surface adsorbed hydroxyl group; Amorphous materials; Annealing; Barium; Crystallization; Dielectric measurements; Gas detectors; Impurities; Infrared detectors; Thermal decomposition; Titanium compounds;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Applications of Ferroelectrics, 2002. ISAF 2002. Proceedings of the 13th IEEE International Symposium on
ISSN :
1099-4734
Print_ISBN :
0-7803-7414-2
Type :
conf
DOI :
10.1109/ISAF.2002.1195920
Filename :
1195920
Link To Document :
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