Speaker
Mr
Chavalit Suksri
(Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai, THAILAND 50200)
Description
Sodium niobate (NaNbO${}_3$;NN) system is a series of alkaline niobate-based ceramics, which is lead-free antiferroelectric material over a wide temperature range of -100 to +360$^{\circ}$C that shows many phase transitions [1]. However, the pure crystallized NaNbO$_3$ ceramic was obtained at high calcination temperatures and showed poor homogeneity with large particle size[2]. In this work, the molten-salt technique was used for synthesis of NaNbO${}_3$ powder. The use of molten-salt in powder preparation is a method to control the size, shape and increase the rate of solid solution reaction[3]. The metal oxides of NaNO${}_3$ and Nb${}_2$O${}_5$ were mixed and ball-milled for 24 h and then mixed with NaCl:KCl salt. After that, the mixed powders were heated at temperatures from 800 to 1050 ${}^{\circ}$C. The phase structure and morphology of NN powders were investigated by using an X-ray diffractrometer (XRD) and a scanning electron microscope (SEM). The phase structure of NN powder corresponded to sodium niobate orthorhombic structure JCPDS file No.01-082-0606. The SEM images demonstrated that NN nano-crystals and agglomeration of particles were obtained. The results confirmed that NN nano-crystals have been successfully prepared by the molten-salt method.
$\textbf{References}$:
1. S. Lanfredi, M. H. Lente, and J. A. Eiras, “Phase Transition at Low Temperature in NaNbO3 Ceramic,” Appl. Phys. Lett., 80 [15] 2731–3 (2002).
2. A. Wu, P. M. Vilarinho, I. M. M. Salvado, and J. L. Baptista, “Sol-Gel Preparation of Lead Zirconate Titanate Powders and Ceramics: Effect of Alkoxide Stabilizers and Lead Precursors,” J. Am. Ceram. Soc., 83 [6] 1379–85 (2000).
3. T. Kimura, “Molten Salt Synthesis of Ceramic Powders”, Advances in Ceramics- Synthesis and Characterization,Processing and Specific Applications,2011
Author
Mr
Chavalit Suksri
(Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai, THAILAND 50200)
Co-author
Dr
Sukum Eitssayeam
(Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai, THAILAND 50200)
