Enhancement of electrical properties of Na_0.5Bi_0.5TiO₃ powders by Ce doping and Ce penetration

For improving the electrical conductivity of Na_0.5Bi_0.5TiO₃ (NBT) powders, the pure NBT powders were produced by sol-gel method and modified by Ce liquid doping and Ce gaseous penetration. The effect of modification on the constitution, structure and electrical properties of Ce-modified Na_0.5Bi_0.5TiO₃ powders was studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), impedance analyzer and resistance meter. The results showed that the addition of Ce helped to reduce the resistivity of Na_0.5Bi_0.5TiO₃ powders, and the penetration method brought the lower resistivity than the doping method. The resistivity of Ce-modified Na_0.5Bi_0.5TiO₃ powders penetrated at 600°C was the lowest, which was decreased to 2.39×10¹ Ω·m from 3.71×10⁶ Ω·m. The doping method made the dielectric constant of Na_0.5Bi_0.5TiO₃ powders decreased, but the penetration method had the reverse effect. The Ce-doped Na_0.5Bi_0.5TiO₃ powders had homogeneous finest particle size, and the particle size of the Ce-penetrated Na_0.5Bi_0.5TiO₃ powders was progressed with the penetration temperature increasing. The doping method did not change the main crystalline phases. But the new phases of Bi, Bi₂Ti₂O₇, Na₂Ti₉O₁₉ and Na₂Ti₆O₁₃ were detected in the Ce-penetrated Na_0.5Bi_0.5TiO₃ powders.