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Title: Dehydration and crystallization kinetics of zirconia-yttria gels

Abstract

Zirconia and zirconia-yttria gels containing 4 and 8 mol% yttria were obtained by coprecipitation and drying at 373 K. The dehydration and crystallization behavior of the dried gels was studied by DSC, TG, and XRD. The gels undergo elimination of water over a wide temperature range of 373--673 K. The peak temperature of the endotherm corresponding to dehydration and the kinetic constants for the process were not influenced by the yttria content of the gel. The enthalpy of dehydration observed was in good agreement with the heat of vaporization data. The dehydration was followed by a sharp exothermic crystallization process. The peak temperature of the exotherm and the activation energy of the process increased with an increase in yttria content, while the enthalpy of crystallization showed a decrease. The ``glow effect`` reduced with increasing yttria content. Pure zirconia crystallizes in the tetragonal form while the zirconia containing 4 and 8 mol% yttria appears to crystallize in the cubic form.

Authors:
; ; ;  [1]
  1. Bhabha Atomic Research Centre, Bombay (India). Metallurgy Division
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
79811
Resource Type:
Journal Article
Journal Name:
Journal of the American Ceramic Society
Additional Journal Information:
Journal Volume: 78; Journal Issue: 2; Other Information: PBD: Feb 1995
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; GELS; DEHYDRATION; ZIRCONIUM OXIDES; CRYSTALLIZATION; YTTRIUM OXIDES; CALORIMETRY; THERMAL GRAVIMETRIC ANALYSIS; X-RAY DIFFRACTION; KINETICS; ACTIVATION ENERGY; ENTHALPY; CRYSTAL STRUCTURE

Citation Formats

Ramanathan, S., Muraleedharan, R.V., Roy, S.K., and Nayar, P.K.K. Dehydration and crystallization kinetics of zirconia-yttria gels. United States: N. p., 1995. Web. doi:10.1111/j.1151-2916.1995.tb08819.x.
Ramanathan, S., Muraleedharan, R.V., Roy, S.K., & Nayar, P.K.K. Dehydration and crystallization kinetics of zirconia-yttria gels. United States. doi:10.1111/j.1151-2916.1995.tb08819.x.
Ramanathan, S., Muraleedharan, R.V., Roy, S.K., and Nayar, P.K.K. Wed . "Dehydration and crystallization kinetics of zirconia-yttria gels". United States. doi:10.1111/j.1151-2916.1995.tb08819.x.
@article{osti_79811,
title = {Dehydration and crystallization kinetics of zirconia-yttria gels},
author = {Ramanathan, S. and Muraleedharan, R.V. and Roy, S.K. and Nayar, P.K.K.},
abstractNote = {Zirconia and zirconia-yttria gels containing 4 and 8 mol% yttria were obtained by coprecipitation and drying at 373 K. The dehydration and crystallization behavior of the dried gels was studied by DSC, TG, and XRD. The gels undergo elimination of water over a wide temperature range of 373--673 K. The peak temperature of the endotherm corresponding to dehydration and the kinetic constants for the process were not influenced by the yttria content of the gel. The enthalpy of dehydration observed was in good agreement with the heat of vaporization data. The dehydration was followed by a sharp exothermic crystallization process. The peak temperature of the exotherm and the activation energy of the process increased with an increase in yttria content, while the enthalpy of crystallization showed a decrease. The ``glow effect`` reduced with increasing yttria content. Pure zirconia crystallizes in the tetragonal form while the zirconia containing 4 and 8 mol% yttria appears to crystallize in the cubic form.},
doi = {10.1111/j.1151-2916.1995.tb08819.x},
journal = {Journal of the American Ceramic Society},
number = 2,
volume = 78,
place = {United States},
year = {1995},
month = {2}
}