A liquidus furnace is useful for determining the maximum temperature at which crystallization will form in a glass, and a minimum temperature at which a glass can be held for extended periods of time without crystal formation and growth.

Samples of glass, frit, or cullet are loaded into a platinum tray then placed into the hot Orton Liquidus Furnace for 1 to 24 hours. The Orton Liquidus Furnace is a specially designed horizontal tube furnace with a controlled, reproducible, linear thermal gradient of approximately 120°C across a 12 long monitored zone, the glass temperature in the tray corresponds to its position along that 12 zone.

The tray is removed hot and allowed to quench cool, freezing the glass in the state it developed inside the furnace. Upon visual, or microscopic inspection, the crystal boundary plane (the Liquidus Point) is located and the temperature of that plane is interpolated from the temperature / position relationship of the known gradient.

Model GTF-MD-1612