Two low-cost chemical methods of sol–gel and the hydrothermal process have been strategically combined to fabricate barium titanate (BaTiO3) nanopowders. This method was tested for various synthesis temperatures (100 °C to 250 °C) employing barium dichloride (BaCl2) and titanium tetrachloride (TiCl4) as precursors and sodium hydroxide (NaOH) as mineralizer for synthesis of BaTiO3 nanopowders. The as-prepared BaTiO3 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 BaTiO3 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 BaTiO3 nanopowders can be stabilized by the sol-hydrothermal method.
Joshua, P (2019). Preparation of meta-stable phases of barium titanate by sol-hydrothermal method. Afribary.com: Retrieved April 21, 2019, from https://afribary.com/works/preparation-of-meta-stable-phases-of-barium-titanate-by-sol-hydrothermal-method
Pearce, Joshua. "Preparation of meta-stable phases of barium titanate by sol-hydrothermal method" Afribary.com. Afribary.com, 15 Apr. 2019, https://afribary.com/works/preparation-of-meta-stable-phases-of-barium-titanate-by-sol-hydrothermal-method . Accessed 21 Apr. 2019.
Pearce, Joshua. "Preparation of meta-stable phases of barium titanate by sol-hydrothermal method". Afribary.com, Afribary.com, 15 Apr. 2019. Web. 21 Apr. 2019. < https://afribary.com/works/preparation-of-meta-stable-phases-of-barium-titanate-by-sol-hydrothermal-method >.
Pearce, Joshua. "Preparation of meta-stable phases of barium titanate by sol-hydrothermal method" Afribary.com (2019). Accessed April 21, 2019. https://afribary.com/works/preparation-of-meta-stable-phases-of-barium-titanate-by-sol-hydrothermal-method