Viscosity and liquidus temperature of quaternary glasses close to an eutectic composition in the CaO–MgO–Al2O3–SiO2 system
The thermal properties of the quaternary glass-forming CaO–MgO–Al 2 O 3 –SiO 2 system were evaluated. Different glass compositions with an expected liquidus temperature—the lowest temperature at which both the crystal phase and the melt are thermodynamically stable—below 1300 °C were melted from pur...
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Published in | Journal of materials science Vol. 52; no. 13; pp. 8280 - 8292 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
New York
Springer US
01.07.2017
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | The thermal properties of the quaternary glass-forming CaO–MgO–Al
2
O
3
–SiO
2
system were evaluated. Different glass compositions with an expected liquidus temperature—the lowest temperature at which both the crystal phase and the melt are thermodynamically stable—below 1300 °C were melted from pure raw materials. Each oxide concentration did not deviate by more than ±3 mol% from that of the centre glass composition of 61.2 SiO
2
, 26.3 CaO, 8.6 Al
2
O
3
and 3.8 MgO. Viscosity data and the liquidus temperatures were determined, as well as the exact compositions of the respective glasses by X-ray fluorescence. It was of special interest for this study, whether small compositional changes have a stronger influence on
T
Liq
or
T
3
. The
T
3
-values, which are the temperatures attributed to a viscosity of 10
3
dPa s—showed a much larger variation and are in the range from 1263 to 1363 °C. An exchange of the network formers Al
2
O
3
or SiO
2
by network modifiers CaO and MgO resulted in a decrease in viscosity. The effect of MgO was also shown by a comparison with glasses of similar compositions but without any MgO. The exchange between Al
2
O
3
and SiO
2
did not show a significant difference in viscosity whereas the substitution of CaO by MgO increased the viscosity. The liquidus temperature varied between 1137 and 1192 °C—less than expected for a composition close to an eutectic system. |
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ISSN: | 0022-2461 1573-4803 |
DOI: | 10.1007/s10853-017-1044-3 |