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Thermal and structural characterization of the ZrO2−x(OH)2xto ZrO2 transition

Published online by Cambridge University Press:  31 January 2011

E Torres-GarciÁa ,
A. Peláiz-Barranco ,
C. Vázquez-Ramos  and
G. A. Fuentes
E Torres-GarciÁa*
Affiliation:
Area de IngenieriÁa QuiÁmica, Universidad A. Metropolitana-Iztapalapa, 09340 Me’xico, D.F., México, and Facultad de QuiÁmica, Instituto de Materiales y Reactivos, Universidad de La Habana, Zapata y G, Vedado, Habana 10400, Cuba
A. Peláiz-Barranco
Affiliation:
Facultad de FiÁsica, Instituto de Materiales y Reactivos, Universidad de La Habana, San Lázaro y L, Vedado, Habana 10400, Cuba
C. Vázquez-Ramos
Affiliation:
Instituto de InvestigacioÁn en Materiales, Universidad Nacional A. de México, México D.F. 04510, México
G. A. Fuentes*
Affiliation:
Area de IngenieriÁa QuiÁmica, Universidad A. Metropolitana-Iztapalapa, 09340 México, D.F., México
*
a)Address all correspondence to this author.gfuentes@xanum.uam.xm,etorres@imre.oc.uh.cu,eneliot@yuahoo.es
a)Address all correspondence to this author.gfuentes@xanum.uam.xm,etorres@imre.oc.uh.cu,eneliot@yuahoo.es
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Abstract

The exothermic process that occurs around 700 K during calcination of ZrO2−x(OH)2x, associated with the crystallization of the low-temperature tetragonal metastable phase of ZrO2, was analyzed using x-ray diffraction, high-resolution thermogravimetric analysis (TGA), nitrogen adsorption, and modulated differential scanning calorimetry (MDSC). High-resolution TGA allowed us to determine the water loss, resulting from condensation of OH− groups. The amount was 0.137 wt% in our case, equivalent to 1.7 × 10−2 mol of H2O/mol of ZrO2. That corresponds to about one −OH group per nm2 being lost in that process. By using MDSC we determined that the change in enthalpy (∆Hglobal = −15.49 kJ/mol of ZrO2) was the result of two parallel contributions. One of them was reversible and endothermic (∆Hrev = 0.11 kJ/mol of ZrO2), whereas the other was irreversible and exothermic (∆Hirrev = −15.60 kJ/mol of ZrO2). The variability and magnitude of the exotherm, as well as the fact that the accompanying weight loss is so small, are consistent with a mechanism involving the formation of tetragonal nuclei, rather than global crystallization, and hence depend on the number of nuclei so formed.

Type
Articles
Information
Journal of Materials Research , Volume 16 , Issue 8 , August 2001 , pp. 2209 - 2212
Copyright
Copyright © Materials Research Society 2001

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References

REFERENCES

1 Zirconium Catalyst Database, CD version 1, Mel Chemicals (1997).Google Scholar
2Málek, J., Benes, L., and Mitsuhahi, T., Powder Diffr. 12, 96 (1997).CrossRefGoogle Scholar
3Urlacher, C. and Mugnier, J., J. Raman Spectrosc. 27, 785 (1996).3.0.CO;2-D>CrossRefGoogle Scholar
4Hammond, L.C. and Cocking, J.L., Powder Diffr. 11, 75 (1996).CrossRefGoogle Scholar
5Garvie, R.C. and Goss, M.P., J. Mater. Sci. 21, 1253 (1986).Google Scholar
6Mercera, P.D.L., Van Ommen, J.G., Doesburg, E.B.M., Burggraaf, A.J., and Ross, J.R.H., Appl. Catal. 57, 127 (1990).Google Scholar
7Livage, J., Doi, K., and Mazieres, C., J. Am. Ceram. Soc. 51, 349 (1968).Google Scholar
8Tani, E., Yoshimura, M., and Somiya, S., J. Am. Ceram. Soc. 66, 11 (1983).CrossRefGoogle Scholar
9Mitsuhashi, T., Ichibara, M., and Tatsuke, U., J. Am. Ceram. Soc. 57, 97 (1974).CrossRefGoogle Scholar
10Garvie, R.C., J. Phys. Chem. 69, 1238 (1965).CrossRefGoogle Scholar
11Yamaguchi, T., Catal. Today 20, 199 (1994).CrossRefGoogle Scholar
12Chen, C-C., Herhold, A.B., Johnson, C.S., and Alivisatos, A.P., Science 276, 398 (1997).CrossRefGoogle Scholar
13Morterra, C., Cerrato, G., Ferroni, L., and Montanaro, L, Mater. Chem. Phys. 37, 243 (1994).CrossRefGoogle Scholar
14Barton, D.G., Soled, S.L., Meitzner, G.D., Fuentes, G.A., and Iglesia, E., J. Catal. 180, 57 (1999).CrossRefGoogle Scholar
15Torres, E., Ph.D. Thesis, Havana University, Havana, Cuba (2000).Google Scholar