Thermal Decomposition of Degassed Barium Titanyl Oxalate: In Comparison to the Solid-State Reaction Mechanism

Abstract

This study examined the formation of BaTiO 3 from degassed barium titanyl oxalate (degassed BTO), which was heat treated at 5001C for 2 h followed by 20 min of aqueous milling, upon further heating. The evolution of BaCO 3 , Ti-based interphase and BaTiO 3 at various temperatures was examined by X-ray diffraction, high-resolution scanning transmission electron microscopy, and electron energy loss spectroscopy. When the degassed BTO was exposed to an aqueous milling, significant amounts of needle-shaped BaCO 3 crystals formed preferentially, which made this system similar to that of a solid-state reaction. However, the formation mechanism of BaTiO 3 observed in this study was found to be different from that of a solid-state reaction due to the different nature of the Ti-based phase.

Effects of TiO2 Starting Materials on the Solid‐State Formation of Li4Ti5O12

“…The solid‐state reaction by the diffusion of the small Li + ion ( r = 90 pm) into the interstitials of TiO 2 seems to be reasonable. A similar solid‐state reaction mechanism for BaTiO 3 from BaCO 3 and TiO 2 has been reported …”

“…A similar solid-state reaction mechanism for BaTiO 3 from BaCO 3 and TiO 2 has been reported. 22,23 To understand further the formation mechanism of Li 4 Ti 5 O 12 from Li 2 CO 3 and TiO 2 , the nature of Li 2 CO 3 should be addressed because the evidence for the existence of this phase could barely be found at the intermediate temperatures of 400°C-500°C, according to Fig. 5.…”