Lyothermal synthesis of nanocrystalline BaTiO{sub 3} and TiO{sub 2} powders

Conference · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:99119

Kaiser, A; Berger, A; Sporn, D ^[1]; Bertagnolli, H ^[2]

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1. Fraunhofer-Institut fuer Silicatforschung, Wuerzburg (Germany)
2. Universitaet Stuttgart (Germany)

The synthesis of BaTiO{sub 3} and powders has been investigated at a temperature of 175{degrees}C and pressures between 0.1 MPa and MPa, starting from TiO{sub 2}{center_dot}xH{sub 2}O and Ba(OH){sub 2}{center_dot}8H{sub 2}O in the solvents of pure water, 1,5-pentanediol and in different mixtures of both. The influence of feedstock concentration and the reaction time on particle growth and habit formation was studied by TEM and XRD. When starting with a higher feedstock concentration at short reaction times (2h), then the BaTiO{sub 3} particle size and habit changed from single crystal dendrites (up to 700 nm in size) to small individual particles (100 nm) with uniform crystallite shapes. An increasing proportion of aggregated particles is observed at extended reaction times at any feedstock concentration investigated The influence of solvent on particle growth was investigated by the use of different 1,5-pentanediol to water mixtures (lyothermal synthesis). By increasing the 1,5-pentanediol to water ratio the primary particle size of BaTiO{sub 3} was reduced from about 700 nm to 15 nm. The reduction of the particle size is probably due to the higher viscosity of 1,5-pentanediol compared to water, and the decrease of diffusivity and concentration of Ba{sup 2+}-ions involved. Hence, the particle size can be controlled by the choice of the solvent mixture.

• OSTI ID: 99119
• Report Number(s): CONF-940911--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM COMPOUNDS
DENDRITES
MICROSTRUCTURE
PARTICLE SIZE
PROCESSING
SYNTHESIS
TEMPERATURE DEPENDENCE
TITANATES
TITANIUM OXIDES
VISCOSITY