Hostname: page-component-586b7cd67f-vdxz6 Total loading time: 0 Render date: 2024-11-23T07:54:27.307Z Has data issue: false hasContentIssue false
  • English
  • Français

Highly sinter-active nanocrystalline RE2O3 (RE = Gd, Eu, Dy) by a combustion process, and role of oxidant-to-fuel ratio in preparing their different crystallographic modifications

Published online by Cambridge University Press:  03 March 2011

V. Bedekar ,
S.V. Chavan  and
A.K. Tyagi
V. Bedekar
Affiliation:
Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
S.V. Chavan
Affiliation:
Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
A.K. Tyagi*
Affiliation:
Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
*
a) Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

Highly sinter-active powders of RE2O3 [rare earth (RE) = Gd, Eu, Dy] have been prepared using the corresponding metal nitrates as the oxidants, and glycine and citric acid as the fuels. Two different oxidant-to-fuel ratios, namely stoichiometric ratio and fuel-deficient ratio were used to explore the possibility of preparing different crystallographic modifications. By a careful control of oxidant-to-fuel ratio, nanocrystalline Eu2O3 and Gd2O3 could be prepared in cubic (C-type) as well as monoclinic (B-type) modifications. However, the high-temperature monoclinic modification could not be obtained for Dy2O3 due to a very high C-to-B-type phase transition temperature. The crystallite size, surface area, and sintering behavior were also studied for powders prepared using different oxidant-to-fuel ratios, and the results showed a remarkable correlation between different fuel contents and powder properties. Some of these powders resulted in pellets of nearly theoretical density. The sintered microstructure was studied by scanning electron microscopy.

Keywords

Combustion synthesisNanoscalePhase transformation
Type
Articles
Information
Journal of Materials Research , Volume 22 , Issue 3 , March 2007 , pp. 587 - 594
Copyright
Copyright © Materials Research Society 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Weller, H.: Colloidal semiconductors Q-particles: Chemistry in the transition region between solid state and molecules. Angew. Chem., Int. Ed. Engl. 32, 41 (1993).CrossRefGoogle Scholar
2Gleiter, H.: Nanocrystalline solids. J. Appl. Crystallogr. 24, 79 (1991).CrossRefGoogle Scholar
3Garvie, R.C.: Stabilization of the tetragonal structure in zirconia microcrystals. J. Phys. Chem. 82, 218 (1978).CrossRefGoogle Scholar
4Encyclopedia of Chemical Technology, Vol. 12, edited by Kroshwitz, J.I., Grant, M.H., and Kirk-Othmer. (John Wiley & Sons, New York, 1994), p. 417.Google Scholar
5Yvars, M.: Ann. Chimie. 10, 17 (1985).Google Scholar
6Adachi, G. and Imanaka, N.: The binary rare-earth oxides. Chem. Rev. 98, 1479 (1998).CrossRefGoogle Scholar
7Foex, M. and Traverse, J.P.: Comments on the allotropic transformations of the rare-earth sesquioxides. Rev. Int. Hautes. Temp. Refract. 3, 429 (1966).Google Scholar
8Sammes, N.M. and Cai, Z.: Ionic conductivity of ceria/yttria stabilized zirconia electrolyte materials. Solid State Ionics 100, 39 (1997).CrossRefGoogle Scholar
9Huang, W., Shuk, P., and Greenblattt, M.: Properties of sol-gel prepared Ce1– x Smx O2–x/2 solid electrolyte. Solid State Ionics 100, 23 (1997).CrossRefGoogle Scholar
10Yoshimura, M. and Suchanek, W.: In situ fabrication of morphology-controlled advanced ceramic materials by soft solution processing. Solid State Ionics 98, 197 (1997).Google Scholar
11Chavan, S.V. and Tyagi, A.K.: Combustion synthesis of nanocrystalline yttria-doped ceria. J. Mater. Res. 19, 474 (2004).CrossRefGoogle Scholar
12Bhaduri, S., Bhaduri, S.B., and Zhou, E.: Auto-ignition synthesis and consolidation of Al2O3-ZrO2 nano/nano composite powders. J. Mater. Res. 13, 156 (1998).CrossRefGoogle Scholar
13Pederson, L.R., Chick, L.A., and Exarhos, G.J.: Metal oxide ceramic powders and thin films and the manufacturer. U.S. Patent No. 5114702. May 19, 1992.Google Scholar
14Ye, T., Guiwen, Z., Weiping, Z., and Shangda, X.: Combustion synthesis and photoluminescence of nanocrystalline Y2O3:Eu phosphors. Mater. Res. Bull. 32, 501 (1997).CrossRefGoogle Scholar
15Yue, Z., Guo, W., Zhou, J., Gui, Z., and Li, L.: Synthesis of nanocrystalline ferrites by sol-gel combustion process: The influence of pH value of solution. J. Magn. Magn. Mater. 270, 216 (2004).CrossRefGoogle Scholar
16Ozuna, O., Hirata, G.A., and McKittrick, J.: Pressure influenced combustion synthesizes of γ- and α-Al2O3 nanocrystalline powders. J. Phys. Condens. Matter 16, 2585 (2004).CrossRefGoogle Scholar
17Chavan, S.V. and Tyagi, A.K.: Preparation and characterization of Sr0.09Ce0.91O1.91, SrCeO3, and Sr2CeO4 by glycine-nitrate combustion: Crucial role of oxidant-to-fuel ratio. J. Mater. Res. 19, 3181 (2004).CrossRefGoogle Scholar
18Handbook of Structural Ceramics, edited by Schwartz, M.M. (McGraw-Hill, New York, 1992) p. 61.Google Scholar
19Perry, R.H. and Chilton, C.H.: Chemical Engineers Handbook 5th ed. (McGraw-Hill, New York, 1975).Google Scholar
20Lange’s Handbook of Chemistry 12th ed., edited by Dean, J.A. (McGraw-Hill, New York, 1979).Google Scholar
21Schumm, R.H., Wagman, D.D., Bailey, S., Evans, W.H., and Parker, V.B.: Selected Values of Chemical Thermodynamic Properties (National Bureau of Standards: Washington, DC, April 1973).Google Scholar