The effect of adding R
2O (R=Li, Na and K) or RO (R=Ba, Mg) on the viscosities of CaO–SiO
2–Al
2O
3 (CaO/SiO
2=0.67, 1.00 or 1.22, Al
2O
3=20 mass%) melts has been measured by rotating crucible viscometer. In addition, structural characterizations of these quenched vitreous samples have been investigated by
27Al and
29Si MAS-NMR spectra.
The viscosities of CaO–SiO
2–Al
2O
3–R
2O quaternary melts decreased with increasing the additive content of Li
2O or Na
2O. However, the viscosity of the melts increased with increasing the additive content of K
2O. In the case of CaO–SiO
2–Al
2O
3–RO quaternary melts, the viscosities of the melts with CaO/SiO
2=0.67 decreased with increasing the additive content of BaO or MgO, however, the viscosities of the melts with CaO/SiO
2=1.00 and 1.22 increased with increasing the additive content of BaO.
In the case of CaO–SiO
2–Al
2O
3–R
2O, the analysis of
27Al MAS-NMR spectra and
29Si MAS-NMR spectra indicated that the degree of polymerization of silicate anions in the glasses decreased with the addition of Li
2O or Na
2O, and that the degree of polymerization of aluminosilicate anions in the glasses increased with the addition of K
2O. It was estimated from the results that the increase in viscosities of CaO–SiO
2–Al
2O
3–K
2O melts was dependent on increase of aluminosilicate anions in the melts with the addition of K
2O.
In the case of CaO–SiO
2–Al
2O
3–RO, the analysis of
27Al MAS-NMR spectra and
29Si MAS-NMR spectra indicated that the degree of polymerization of silicate and aluminosilicate anions in the glasses decreased with the addition of MgO. The degree of polymerization of aluminosilicate anions in the glasses increased with the addition BaO. It was estimated from the results that the increase in viscosities of CaO–SiO
2–Al
2O
3–BaO melts was dependent on increase of aluminosilicate anions in the melts with the addition of BaO.
抄録全体を表示