Preparation of meta-stable phases of barium titanate by Sol-hydrothermal method

Journal Article · Sun Nov 15 00:00:00 EST 2015 · AIP Advances

DOI:https://doi.org/10.1063/1.4935645· OSTI ID:22492178

Selvaraj, Mahalakshmi ^[1]; Venkatachalapathy, V. ^[2]; Karazhanov, S. ^[3]

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1. Department of Physics, R.D. Govt. Arts College, Tamilnadu, Sivaganga - 630561 (India)
2. Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, P.O Box 1048 Blindern, NO-0316 Oslo (Norway)
3. Department of Solar Energy, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway)

Two low-cost chemical methods of sol–gel and the hydrothermal process have been strategically combined to fabricate barium titanate (BaTiO{sub 3}) nanopowders. This method was tested for various synthesis temperatures (100 °C to 250 °C) employing barium dichloride (BaCl{sub 2}) and titanium tetrachloride (TiCl{sub 4}) as precursors and sodium hydroxide (NaOH) as mineralizer for synthesis of BaTiO{sub 3} nanopowders. The as-prepared BaTiO{sub 3} powders were investigated for structural characteristics using x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The overall analysis indicates that the hydrothermal conditions create a gentle environment to promote the formation of crystalline phase directly from amorphous phase at the very low processing temperatures investigated. XRD analysis showed phase transitions from cubic - tetragonal - orthorhombic - rhombohedral with increasing synthesis temperature and calculated grain sizes were 34 – 38 nm (using the Scherrer formula). SEM and TEM analysis verified that the BaTiO{sub 3} nanopowders synthesized by this method were spherical in shape and about 114 - 170 nm in size. The particle distribution in both SEM and TEM shows that as the reaction temperature increases from 100 °C to 250 °C, the particles agglomerate. Selective area electron diffraction (SAED) shows that the particles are crystalline in nature. The study shows that choosing suitable precursor and optimizing pressure and temperature; different meta-stable (ferroelectric) phases of undoped BaTiO{sub 3} nanopowders can be stabilized by the sol-hydrothermal method.

• OSTI ID: 22492178
• Journal Information: AIP Advances, Vol. 5, Issue 11; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMORPHOUS STATE
BARIUM CHLORIDES
ELECTRON DIFFRACTION
FERROELECTRIC MATERIALS
GRAIN SIZE
HYDROTHERMAL SYNTHESIS
NANOSTRUCTURES
ORTHORHOMBIC LATTICES
PARTICLES
PHASE TRANSFORMATIONS
POWDERS
SCANNING ELECTRON MICROSCOPY
SODIUM HYDROXIDES
SOL-GEL PROCESS
TITANATES
TITANIUM CHLORIDES
TRANSMISSION ELECTRON MICROSCOPY
TRIGONAL LATTICES
X-RAY DIFFRACTION