Abstract: The microstructure and dielectric properties of ternary system BaTiO₃-Nb₂O₅-Ni₂O₃ were investigated. XRD analyses indicate that Nb₂O₅/Ni₂O₃ co-doped BaTiO₃ ceramics have pseudo-cubic structures. The solubility of Nb in BaTiO₃ with 1.0 mol% Ni is <4.0mol%. SEM results show that the grain size of BaTiO3 ceramics initially increases and then decreases with the increase of Nb amount. Also the room-temperature dielectric constant and loss, as well as the capacitance variation values at low and high temperature range initially increase and then decrease with the increase of Nb amount. DSC results show that the Curie temperature of the BaTiO₃ ceramics is shifted to higher temperatures by Nb addition. The modification of the dielectric properties of the ceramic system is considered to be correlated with the grain size and the shift of phase transition temperature by the additives. The novel X8R material developed in the BaTiO₃-Nb₂O₅-Ni₂O₃ system in the present work is very promising for preparation of X8R MLCCs with large capacitance.

Key words: BaTiO3, X8R, dielectric properties, Curie temperature