Powrót do 3/20163/2016 pp. 135-140
Niobiany ziem rzadkich – właściwości i zastosowania
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Rare earth niobates are a very interesting group of materials. These compounds have different properties which could be changed in a wide range by appropriate doping. X-Ray diffraction examinations for some compounds of RE3NbO7 group were shown. All peaks agree with diffraction patterns. Phases from other elements are not reported. These materials were divided into three space groups depending on ionic radius of RE3+. The most important from applicational point of view is defected-fluorite type structure which is reached for the smallest RE3+ cations. Surface morphology made by Scanning Electron Microscopy was shown. The microstructure of examined materials varies grain size what is connected with ionic radius RE3+. Electrical measurements made in dry argon atmosphere show that the highest values of ionic conductivity were reached for two last lanthanides rare earth niobates Yb3NbO7, Lu3NbO7 and for Y3NbO7. Contained optical properties measurements show that Spark Plasma Sintering enables to obtain Lu3NbO7 which is transparent for visible light.
Słowa kluczowerare earth niobates, doping, ionic conductors, protonic conductors
Literatura1. An, L., Ito, A., Goto, T., Fabrication of transparent Lu3NbO7 by spark plasma sintering, Materials Letters, 2011, 65, pp. 3167-3169.
2. Chesnaud, A., Braida, M.-D., Estrade, S., Peiro, F., Tarancon, A., Morata, A., Dezenneau, G., High-temperature anion and proton conduction in RE3NbO7 (RE = La, Gd, Y, Yb, Lu) compounds, Journal of the European Ceramic Society, 2015, 35, pp. 3051–3061.
3. Hinatsu, Y., Doi, Y., High-temperature X-ray diffraction measurements of fluorite-related rare earth antimonates Ln3SbO7 (Ln=Nd, Tb) and their magnetic properties, Journal of Solid State Chemistry, 2014, 217, pp. 16-21.
4. Kahn-Harari, A., Mazerolles, L., Michel, D., Robert, F., Structural Description of La3NbO7, Journal of Solid State Chemistry, 1995, 116, pp.103-106.
5. Małys, M., Hołdynski, M., Kroka, F., Wróbel, W., Dygas, J.R., Pirovano, C., Vannier, R.-N., Capoen, E., Abrahams, I., Investigation of transport numbers in yttrium doped bismuth niobates, Journal of Power Sources, 2009, 194, pp. 16–19.
6. Navrotsky, A., Lee, W., Mielewczyk-Gryń, A., Ushakov, S., Anderko, A., Wu, H., Riman, R., Thermodynamics of solid phases containing rare earth oxides, J. Chem. Thermodynamics, 2015, 88, pp. 126-141.
7. Siqueira, K., Soares, J., Granado, E., Bittar, E., de Paula, A., Moreira, R., Dias, A., Synchrotron X-ray diffraction and Raman spectroscopy of Ln3NbO7 (Ln=La, Pr, Nd, Sm-Lu) ceramics obtained by molten-salt synthesis, Journal of Solid State Chemistry, 2014, 209, pp. 63–68.