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In this scenario, the transition temperature is known as the calorimetric ideal glass transition temperature T 0c. In this view, the glass transition is not merely a kinetic effect, i.e. merely the result of fast cooling of a melt, but there is an underlying thermodynamic basis for glass formation. The glass transition temperature:
Liquidus temperature curve in the binary glass system SiO 2-Li 2 O. For impure substances, e.g. alloys, honey, soft drink, ice cream, etc. the melting point broadens into a melting interval. If the temperature is within the melting interval, one may see "slurries" at equilibrium, i.e. the slurry will neither fully solidify nor melt.
Fused quartz is used for high-temperature applications such as furnace tubes, lighting tubes, melting crucibles, etc. [74] However, its high melting temperature (1723 °C) and viscosity make it difficult to work with. Therefore, normally, other substances (fluxes) are added to lower the melting temperature and simplify glass processing. [75]
Borosilicate glass is created by combining and melting boric oxide, silica sand, soda ash, [6] and alumina. Since borosilicate glass melts at a higher temperature than ordinary silicate glass, some new techniques were required for industrial production.
The manufacturing process for soda–lime glass consists in melting the raw materials, which are the silica, soda (Na 2 O), hydrated lime (Ca(OH) 2), dolomite (CaMg(CO 3) 2, which provides the magnesium oxide), and aluminium oxide; along with small quantities of fining agents (e.g., sodium sulfate (Na 2 SO 4), sodium chloride (NaCl), etc.) in a glass furnace at temperatures locally up to 1675 ...
Glass Furnace by Siemens hist. 1878 Siemens Regenerator Furnace hist. 1885 in 4 Views. A glass melting furnace is designed to melt raw materials into glass. [1] Depending on the intended use, there are various designs of glass melting furnaces available. [2] [3] [4] They use different power sources. These sources are mainly fossil fueled or by ...
Melting point (glass melt homogenization and fining) 3 4 Working point (pressing, blowing, gob forming) 4 5 Flow point 6.6 7.6 Littleton Softening point (glass deforms visibly under its own weight. Standard procedures ASTM C338, ISO 7884-3) 8–10 9–11 Dilatometric softening Point, T d, depending on load [2] 10.5 11.5
Soda–lime glass (for containers) [2] Borosilicate (low expansion, similar to Pyrex, Duran) Glass wool (for thermal insulation) Special optical glass (similar to Lead crystal) Fused silica Germania glass Germanium selenide glass Chemical composition, wt% 74 SiO 2, 13 Na 2 O, 10.5 CaO, 1.3 Al 2 O 3, 0.3 K 2 O, 0.2 SO 3, 0.2 MgO, 0.01 TiO 2, 0. ...