TY - JOUR
T1 - Crystallization kinetics of Na2O · 3SiO2
AU - Uhlmann, D. R.
AU - Scherer, G. W.
N1 - Funding Information:
Financial support for the present work was provided by the National Aeronautics and Space Administration, and by Owens—Illinois Inc. (who provided G. S. with the Owens—Illinois Fellowship in Materials Science). This support is gratefully acknowledged, as are stimulating discussions with Dr. K. A. Jackson of Bell Telephone Laboratories.
PY - 1975/5
Y1 - 1975/5
N2 - The crystallization kinetics of Na2O · 3SiO2 have been determined over the temperature range between 600°C and 800°C. The (metastable) melting point of this material has been determined as 811 ± 3°C. The growth rate vs. temperature relation exhibits the maximum generally found for glass-forming systems, with the maximum growth rate (3.3 x 10-6 cm sec-1) observed at 735 °C. Under all conditions of growth, the crystal-liquid interfaces are faceted. This is indicative of significant growth rate anisotropy, and suggests that the entropy of fusion is large in Jackson's sense (ΔSfM &62- 4R, where ΔSfM is the molar entropy of fusion). Assuming ΔSfM = 4R, by analogy with the characteristics of Na2O · 2SiO2, the reduced growth rate versus undercooling relation has been constructed. The form of this relation - a straight line of positive slope passing through the origin - is suggestive of growth by a screw dislocation mechanism. The magnitudes of the growth rates are in close accord with the predictions of the standard model for such growth.
AB - The crystallization kinetics of Na2O · 3SiO2 have been determined over the temperature range between 600°C and 800°C. The (metastable) melting point of this material has been determined as 811 ± 3°C. The growth rate vs. temperature relation exhibits the maximum generally found for glass-forming systems, with the maximum growth rate (3.3 x 10-6 cm sec-1) observed at 735 °C. Under all conditions of growth, the crystal-liquid interfaces are faceted. This is indicative of significant growth rate anisotropy, and suggests that the entropy of fusion is large in Jackson's sense (ΔSfM &62- 4R, where ΔSfM is the molar entropy of fusion). Assuming ΔSfM = 4R, by analogy with the characteristics of Na2O · 2SiO2, the reduced growth rate versus undercooling relation has been constructed. The form of this relation - a straight line of positive slope passing through the origin - is suggestive of growth by a screw dislocation mechanism. The magnitudes of the growth rates are in close accord with the predictions of the standard model for such growth.
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U2 - 10.1016/0022-0248(75)90042-1
DO - 10.1016/0022-0248(75)90042-1
M3 - Article
AN - SCOPUS:49549143018
SN - 0022-0248
VL - 29
SP - 12
EP - 18
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
IS - 1
ER -