- Liquidus temperature
[
2-Li2O, based on 91 published data collected in [http://www.sciglass.info/ SciGlass] ; model fit from [http://www.glassproperties.com/liquidus Glassproperties.com] ]
The liquidus temperature, TL or Tliq, is mostly used for
glass es andalloy s. It specifies the maximum temperature at whichcrystal s can co-exist with the melt inthermodynamic equilibrium . Above the liquidus temperature the material ishomogeneous . Below the liquidus temperature more and morecrystal s begin to form in the melt if one waits a sufficiently long time, depending on the material. However, even below the liquidus temperaturehomogeneous glass es can be obtained through sufficiently fast cooling, i.e., through kineticinhibition of thecrystallization process.The crystal phase that crystallizes first on cooling a substance to its liquidus temperature is termed primary crystalline phase or primary phase. The composition range within which the primary phase remains constant is known as primary crystalline phase field.
The liquidus temperature is important in the
glass industry because crystallization can cause severe problems during theglass melting and forming processes, and it also may lead to product failure.The liquidus temperature can be contrasted to the solidus temperature. The solidus temperature quantifies the point at which a material completely solidifies (crystallizes). The liquidus and solidus temperatures do not necessarily align or overlap; if a gap exists between the liquidus and solidus temperatures, then within that gap, the material consists of solid and liquid phases simultaneously (like a "slurry").
See also
*
Phase diagram
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