Abstract

Glasses of the 6Na₂O · хB₂O₃ · (86 – x)SiO₂ · 8Fe₂O₃ compositions, where x varies from 16 to 31 mol %, are studied by X-ray powder diffractometry and dilatometry. The glasses were preliminarily held at a temperature of 550°C for 8–144 h. It is determined that there are crystalline phases of magnetite and hematite in the studied glasses in addition to the amorphous component. The hematite content gradually decreases as the amount of SiO₂ increases and it completely disappears when the SiO₂ concentration is higher than 65 mol %. As the duration of the heat treatment increases, the amount of magnetite does not change. At the maximum duration of the heat treatment (144 h), crystallization of the silica phases—tridymite and cristobalite—is observed for all the studied glasses. The stability of the glass transition temperature of all glasses with an increase of the duration of the heat treatment indicates that the coexisting phases of phase-separated glass reach their equilibrium compositions after 8 hours. The crystallization of silica in the glasses is accompanied by a decrease in the glass transition temperature of the low-viscosity phase.

中文翻译：

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不同SiO 2含量的Na 2 O–B 2 O 3 –SiO 2 –Fe 2 O 3体系在玻璃中的结晶

摘要

所述6NA的眼镜₂ O· х乙₂ ö ₃ ·（86 - X）的SiO ₂ ·8FE _2层ö ₃的组合物，其中X为16〜31％（摩尔）不同而不同，是由X射线粉末衍射法和膨胀测定研究。预先将玻璃杯在550°C的温度下放置8–144小时。可以确定，除了非晶组分外，在研究的玻璃中还存在磁铁矿和赤铁矿的晶相。赤铁矿含量的二氧化硅的量逐渐减少₂增加，并完全消失时在SiO ₂浓度高于65mol％。随着热处理时间的增加，磁铁矿的量不会改变。在热处理的最大持续时间（144小时）中，所有研究的玻璃均观察到二氧化硅相的结晶（三水铝石和方石英）。随着热处理时间的增加，所有玻璃的玻璃化转变温度的稳定性表明，相分离的玻璃的共存相在8小时后达到其平衡组成。玻璃中二氧化硅的结晶伴随着低粘度相的玻璃化转变温度的降低。