Dehydration and crystallization kinetics of zirconia-yttria gels

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1995.tb08819.x· OSTI ID:79811

Ramanathan, S; Muraleedharan, R V; Roy, S K; Nayar, P K.K. ^[1]

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1. Bhabha Atomic Research Centre, Bombay (India). Metallurgy Division

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.

• Sponsoring Organization: USDOE
• OSTI ID: 79811
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 2 Vol. 78; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
CALORIMETRY
CRYSTAL STRUCTURE
CRYSTALLIZATION
DEHYDRATION
ENTHALPY
GELS
KINETICS
THERMAL GRAVIMETRIC ANALYSIS
X-RAY DIFFRACTION
YTTRIUM OXIDES
ZIRCONIUM OXIDES