Preparation and characterization of K0.5Bi0.5TiO3 particles synthesized by a stirring hydrothermal method

• Published in: Ceramics international 2016-02, Vol.42 (3), p.3751-3756
• Main Authors: Krad, Imen, Bidault, Olivier, Geoffroy, Nicola, Maaoui, Mohamed EL
• Format: Article
• Language: English
• Subjects: C. Dielectric properties; Hydrothermal synthesis; K0.5Bi0.5TiO3; Nanoparticule
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2015.10.158

Nanoparticles of potassium bismuth titanate K0.5Bi0.5TiO3 (KBT) with an average particle size of 38nm were prepared using a stirring hydrothermal method. The pure KBT was obtained in 8h reaction time instead of 24–48h for conventional hydrothermal method. X-ray diffraction, Raman spectroscopy and TG analysis were used to check the proportion of hydroxyl group existing into the crude and the calcined KBT. A Hydroxyl group was found to affect the crystallite structure parameters and cell volume. When temperature increases from 25 to 1050°C, the tetragonal structure presents a c/a ratio which decreases from 1.048 to 1.012. TG analysis and Raman vibration at high frequencies show that c/a is affected by hydroxyl group content below 750°C and by potassium and bismuth vacancies above this temperature. The ceramic KBT showing a 300nm size presents an improved εr=780 and a dielectric loss tanδ=0.062 at room temperature. Electric conductivity σac was also lowered to 10−6(Ωm)−1 with an activation energy change at 673K from 0.35 to 0.605eV.