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Ultra low expansion glass has an coefficient of thermal expansion of about 10 −8 /K at 5–35 °C. [2] It has a thermal conductivity of 1.31 W/(m·°C), thermal diffusion of 0.0079 cm 2 /s, a mean specific heat of 767 J/(kg·°C), a strain point of 890 °C [1634 °F], and an estimated softening point of 1490 °C [2714 °F], an annealing point ...
A number of materials contract on heating within certain temperature ranges; this is usually called negative thermal expansion, rather than "thermal contraction".For example, the coefficient of thermal expansion of water drops to zero as it is cooled to 3.983 °C (39.169 °F) and then becomes negative below this temperature; this means that water has a maximum density at this temperature, and ...
Guitar slide made of borosilicate glass. Borosilicate glass is a type of glass with silica and boron trioxide as the main glass-forming constituents. Borosilicate glasses are known for having very low coefficients of thermal expansion (≈3 × 10 −6 K −1 at 20 °C), making them more resistant to thermal shock than any other common glass.
For a single component system, the "standard" three parameters are the isothermal compressibility , the specific heat at constant pressure , and the coefficient of thermal expansion . For example, the following equations are true:
The extremely low coefficient of thermal expansion, about 5.5 × 10 −7 /K (20–320 °C), accounts for its remarkable ability to undergo large, rapid temperature changes without cracking (see thermal shock). Phosphorescence in fused quartz from an extremely intense pulse of UV light in a flashtube, centered at 170 nm
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. ...
The material exhibits a particularly low thermal expansion, with a mean value of 0 ± 0.007×10 −6 K −1 within the temperature range of 0 to 50 °C. [22] High 3D homogeneity [22] with few inclusions, bubbles and internal stria. Hardness similar to that of borosilicate glass. High affinity for coatings. Low helium permeability. Non-porous.
Negative and positive thermal expansion hereby compensate each other to a certain amount if the temperature is changed. Tailoring the overall thermal expansion coefficient (CTE) to a certain value can be achieved by varying the volume fractions of the different materials contributing to the thermal expansion of the composite. [8] [20]