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CONTURAX / Physical and Chemical Properties	- Introduction | Profiles | Properties -
Borosilicate 3.3 Glass

Physical Data

Mean coefficient of linear expansion a 20/300 acc. to DIN 52328 3.3 · 10-6 K-1 Transformation temperature Tg 525 ºC Temperature fixed points at viscosity h in dPa · s:                1013 upper annealing point 560 ºC                107.6 softening point 825 ºC                104 working point 1260 ºC Maximum short-time working temperature 500 ºC Density r 2.23 g · cm-3 Modulus of elasticity E, Young's modulus 64 · 103 N · mm-2 Poisson's ratio m 0.20 Thermal conductivity lw at 90 ºC 1.2 W · m-1 · K-1 Temperature for the specific electrical resistance of 108 W · cm tk 100 250 ºC Logarithm of the electric volume resistance (W · cm)       at 250 ºC 8       at 350 ºC 6.5 Dielectric properties (1MHz, 25 ºC) Dielectric figure e 4,6 Dielectric loss factor tan d 37 · 10-4 Refractive index nd (l = 587,6 nm) 1.473 Stress-optical constant ( DIN 52314) K 4.0 · 10-6 mm2 · N-1

Chemical Composition (main components in approx. weight %)	SiO2 B2O3 Na2O + K2O Al2O3 81 13 4 2

Chemical Data

Hydrolytic Class (ISO 719) HGB 1 Acid Class (DIN 12 116) Class S 1 Alkali Class (ISO 695) Class A 2 Conturax (Borosilicate Glass 3.3) is highly resistant to water, neutral and acid solutions, concentrated acids and acid mixtures, and to chorine, bromine, iodine and organic substances. The chemical resistance of this glass is superior to that of most metals and other materials, even when exposed to long processing periods and temperatures above 100 ºC. A slight release of mainly monovalent ions takes place after exposure of the glass to water or acids. A very thin layer of impervious silica gel is subsequently formed on the surface of the glass, which in turn slows clown further attack. Acid, hot phosphoric acid and alkaline solutions attack the glass surface as a function of concentration and temperature.

Transmission (%)	Wavelength (nm)

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