Synthesis and Dielectric Properties of Niobia Coating on BaTiO_3

摘要

Different from conventional powder mixing, this study demonstrates a method of homogeneous coating for niobia (Nb_2O_5) on ferroelectric barium titanate (BaTiO_3) powders. The precipitation of Nb coating with pH has been determined quantitatively by the inductance-coupled plasma method. Crystalline phases were determined by X-ray difrractometry, and the formation of a "core-shell" structure with a Nb concentration gradient was observed by a transmission electron microscope with X-ray energy-dispersive spectroscopy. The dielectric constant (K) of the samples prepared by the nanocoating method showed a more stable temperature coefficient of capacitance and well satisfied the requirements of X7R.