An improved apparatus for the determination of liquidus temperatures and rates of crystal growth in glasses

Abstract

The liquidus te mperature of a glass is t he highest temperature at which equilibrium can coexist between the molten glass and the primary crystalline phase. An improved temperature-grad ient apparatus is d escribed for thc rapid d etermination of liquidus temperatures and rates of crystal growth in glasses. In this method the use of small glass fragmcnts confined in the cells of a platinum a ll oy holder largely eliminates the crror inherent in previous gradient method s. The proced ure is s imple and rapid. Liquidus tempe ratures in the range from 950° to 1,225°C were determined to a precision of 4 d eg rees C.Hates of crystal growth were found to be linear. The usefulness to the glass technologist of data obtained by this method is indicated.

Shape of the liquidus surface as a criterion of stable glass formation

“…. Grauer and Hamilton [8] have pomted out that m any study of glass stability one must take in~o account (1) the liquidus temperature or maXImum temperature at which equilibrium exist s b etween the glass and the primary crys talline. phase and (2) the rates of crystal growth at vaI'lo~s ~emperatures.…”

Advanced approaches to functional glasses

“…Heat treatments of a sample glass in a capillary are carried out at various temperatures in temperature gradient atmosphere which is controlled to have a linear relationship with the position along the axis of the tubular furnace. Conventional temperature gradient technique was applied to discrete glass samples [8], but combinatorial glass sample melter and annealer manages a glass rod sample in a capillary. Time-temperature-transformation (T-T-T) curves [9] can be determined within a week by tracing the temperatures corresponding to the ends of the opaque part of the capillaries in the order of heat treatment times.…”

“…Heat treatments of a sample glass in a capillary are carried out at various temperatures in the temperature gradient atmosphere which is related linearly with the position along the axis of the tubular furnace. The conventional temperature gradient technique was applied to discrete glass samples [8], but the combinatorial glass sample melter and annealer manages a glass rod sample in a capillary. …”

Advanced Approaches to Functional Glasses

“…Heat treatments of a sample glass in a capillary are carried out at various temperatures in temperature gradient atmosphere which is controlled to have a linear relationship with the position along the axis of the tubular furnace. Conventional temperature gradient technique was applied to discrete glass samples, 8) but Combinatorial Glass Sample Melter and Annealer manages a glass rod sample in a capillary. TimeTemperatureTransformation curves 9) can be determined within a week by tracing the temperatures corresponding to the ends of the opaque part of the capillaries in the order of heat treatment times.…”