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Dehydration and Crystallization Kinetics of Zirconia‐Yttria Gels
Author(s) -
Ramanathan Srinivasan,
Muraleedharan Ramayi V.,
Roy Sujit Kumar,
K. Padmanabha,
Nayar Krishnan
Publication year - 1995
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1995.tb08819.x
Subject(s) - yttria stabilized zirconia , crystallization , cubic zirconia , dehydration , materials science , enthalpy , activation energy , chemical engineering , tetragonal crystal system , chemistry , crystallography , thermodynamics , crystal structure , metallurgy , ceramic , biochemistry , physics , engineering
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.