20-22 May 2015
Asia/Bangkok timezone
The Centennial Celebration of General Relativity Theory and 80 Years of Thai Physics Graduate

Phase Formation and Microstructure of Sodium Niobate Powder Synthesized Using Molten-salt Technique

20 May 2015, 15:15
15m
Phokheetara Grand Ballroom ()

Phokheetara Grand Ballroom

Oral presentation Material Physics, Nanoscale Physics and Nanotechnology Material Physics, Nanoscale Physics and Nanotechnology

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

Primary 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)

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