SiO₂-Fe₂O₃-K₂O系ガラスの高膨脹性とFe-leucite生成との関係

抄録

The glasses in the system SiO₂-Fe₂O₃-K₂O by heating turn into glass-ceramics by precipitating Fe-leucite (4SiO₂⋅Fe₂O₃⋅K₂O) crystals. Thermal expansion of the glass-ceramics is distinctly high compared to the original glasses. Detailed studies show that:
1) Fe-leucite crystals precipitate by the heat-treatment at 800°-1160°C of the glasses 4SiO₂⋅K₂O⋅xFe₂O₃ (x=0.65-1). The amount of the crystals increases as x approaches to 1.
2) Thermal expansion coefficients of glass-ceramics are higher the more the amounts of crystals are, and are almost equivalent to those expected for glass-crystal composite.
3) The Fe-leucite crystals are tetragonal at 30°C and invert to cubic symmetry at about 570°C.