Microstructural investigation of sol-gel BZT powders

作者：Thanachayanont Chanchana^*; Yordsri Visittapong; Kijamnajsuk Suphakan; Binhayeeniyi Nawal; Muensit Nantakan

来源：Materials Letters, 2012, 82: 205-207.

DOI：10.1016/j.matlet.2012.05.075

• BZT
• Tetragonality
• XRD
• CBED
• TEM

Microstructure is known to be one of the most important factors affecting dielectric constant, Curie temperature, electrical conductivity and breakdown voltage of Ba(Zr5Ti1 - x)O-3 (BZT) powders. Grain sizes of sol-gel derived BZT are known to be much smaller than those prepared by solid-state reaction enabling low sintering temperatures to be used during subsequent processing. In this study, crystal structures of Ba(ZrxTi1 - x)O-3, x=0, 0.05, 0.10, 0.15 and 0.20, prepared by the sol-gel technique were investigated using Rietveld refinement X-ray Diffraction (XRD) and convergent beam electron diffraction (CBED). Lattice parameters obtained from XRD were used for CBED pattern simulation. The experimental CBED patterns taken from individual grains matched well with the simulated results. Morphology of the Bit powders was investigated using transmission electron microscopy (TEM). It was found that as the zirconium content increased, both c-and a-lattice constants gradually increased. The tetragonality (c/a) decreased to almost unity at x=0.15 which was smaller than the value x=0.20 previously reported for the Bit powders prepared by mixed oxide method. Hence, the nano-grain sizes ranging from 133.4 to 214.8 nm in the sol-gel Bit powders were found to modify the Zr content, x, needed to promote the phase transition from the tetragonal to cubic lattice structure.

• 出版日期2012-9-1