Crystallization kinetics of lead metasilicate

T. S. Neiman, H. Yinnon, Donald R Uhlmann

Research output: Contribution to journalArticle

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Abstract

The crystallization kinetics of PbO·SiO2 have been determined from 500°C. The thickness of the crystal layer was found to increase linearly with time; and the interface morphology was faceted at all temperatures. The heat of fusion of PbO·SiO2 was estimated in two ways: (1) from DSC measurements of heat capacities of glassy and crystalline PbO·SiO2 combined with tabulated ΔS0(298) values; and (2) from direct mesurements using heat-flux DSC. The average value of ΔHf obtained is 8.1 × 103 cal mol-, corresponding to an entropy of fusion of 3.9R. The growth process of PbO·SiO2 is interface-controlled, with an interface site factor which increases with increasing undercooling. The plot of log (growth rate × viscosity) versus (T ΔT-1 can be described by two straight lines with different slopes. The slopes correspond to edge surface energies of 113 and 51 erg cm-2, leading to values of 0.35 and 0.16 respectively for the ratio σM/ΔHfM (were σM is the molar surface energy and ΔHfM is the molar heat of fusion). It is shown that the crystal growth data on PbO·SiO2 are within an order of magnitude of the theoretically-predicted values based on the standard model of surface-nucleation controlled crystal growth, at least at small undercoolings. The data seem, however, at variance with predictions based on computer simulations of crystal growth using the measured heat of fusion. The excellent glass-formability of PbO·SiO2, in spite of its high fluidity, may be explained by this deviation from expected behavior and by the absence of effective nucleating heterogeneities.

Original languageEnglish (US)
Pages (from-to)393-403
Number of pages11
JournalJournal of Non-Crystalline Solids
Volume48
Issue number2-3
DOIs
StatePublished - 1982
Externally publishedYes

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heat of fusion
Crystallization kinetics
crystal growth
Fusion reactions
Lead
Crystallization
Crystal growth
supercooling
crystallization
Undercooling
surface energy
kinetics
Interfacial energy
slopes
Fluidity
heat flux
Formability
computerized simulation
fusion
plots

ASJC Scopus subject areas

  • Ceramics and Composites
  • Electronic, Optical and Magnetic Materials

Cite this

Crystallization kinetics of lead metasilicate. / Neiman, T. S.; Yinnon, H.; Uhlmann, Donald R.

In: Journal of Non-Crystalline Solids, Vol. 48, No. 2-3, 1982, p. 393-403.

Research output: Contribution to journalArticle

Neiman, T. S. ; Yinnon, H. ; Uhlmann, Donald R. / Crystallization kinetics of lead metasilicate. In: Journal of Non-Crystalline Solids. 1982 ; Vol. 48, No. 2-3. pp. 393-403.
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