Effect of NaNbO3 Crystalline Aggregates on the Electrical Properties of SiO2-Na2O-Nb2O5 Glass-Ceramics

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Abstract:

The presence of NaNbO3 crystallites in a glass matrix has scientific and technological interest due to their electrical properties and potential applications in microwave, pyroelectric and piezoelectric devices. A glass with the composition 60SiO2-30Na2O-10Nb2O5 (% mole) was prepared by the melt-quenching method. NaNbO3 microcrystallites were precipitated on the surface of the glass by heat-treatment. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, dc and ac conductivity measurements were used in the study of the glass and glassceramic materials. The number of particles, precipitated in the surface of the glass-ceramic samples, increases from the 650 to the 750°C and decrease in the 800°C sample. In all these samples the particles size thickness increases with the rise of the heat-treatment temperature. In the 750 and 800°C samples it was observed the presence of a white surface layer formed by NaNbO3 crystallites aggregations. The dc conductivity (σdc) decreases with the rise of the heat –treatment temperature up to 750°C and the dielectric constant value, at 1kHz and room temperature, has a maximum value of 34.94 for the 800 °C treated sample.

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Materials Science Forum (Volumes 514-516)

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274-279

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May 2006

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© 2006 Trans Tech Publications Ltd. All Rights Reserved

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[1] JS Andrade, AG Pinheiro, IF Vasconcelos, JM Sasaki, JAC Paiva, MA Valente, ASB Sombra, J. Phys.: Cond. Matter 11 (1999) 4451-460.

Google Scholar

[2] MPF Graça, MA Valente, MGF Silva, J. Non-Cryst. Solids, 325 (2003) 267-274.

Google Scholar

[3] A. Molak, J. Kubacki, Cryst. Res. Technol, 36 (8-19), 2001, 893-902.

Google Scholar

[4] B. Jiménez, R. Jiménez, A. Castro, L. Pardo, J. Eur. Ceram. Soc., 24, 2004, 1521-1524.

Google Scholar

[5] L.A. Reznichenko, L.A. Shilkina, O.N. Razumovskaya, S.I. Dudkina, E.S. Gagarina, A.V. Borodin, Inorganic Materials, 39 (2), 2003, 139-150.

DOI: 10.1023/a:1022194512814

Google Scholar

[6] ZX Shen, XB Wang, MH Kuok, SH Tang, J. of Raman Spectr., 29, 1998, 379-384.

Google Scholar

[7] S. Lanfredi, L. Dessemond, ACM Rodrigues, J. Eur. Ceram. Soc., 20, 2000, 983-990.

Google Scholar

[8] BT Matthias, JP Remaika, Physical Review, 82 (5), 1951, 727-731.

Google Scholar

[9] SW Martin, CA Angell, J. Non-Cryst. Solids, 83 (1986) 185-207.

Google Scholar

[10] GO Karapetyan, VV Loboda, DK Tagantsev, J. Non-Cryst. Solids, 283 (2004) 114-118.

Google Scholar

[11] R. Jenkins, R.L. Snyder, Introduction to X-ray powder diffractometry, , John Wiley, N.Y. (1996).

Google Scholar

[12] AA Lipovski, DK Tagantsev, AA Vetrov, OV Yanush, Opt. Materials, 21 (2003), 749-757.

Google Scholar

[13] T. Cardinal, E. Fargin, G. Le Flem, S. Leboiteux, J. Non-Cryst. Solids, (1997).

Google Scholar

[14] YD Juang, SB Day, YC Wang, WY Chou, JS Wang, ML Hu, WS Tse, Solid State Comm. 111(1999) 723-728.

Google Scholar

[15] MPF Graça, MGF Silva, MA Valente, J. Non-Cryst. Solids, 351 (33-36) (2005), 2951-2957.

Google Scholar