Chemical properties

of Micro Glass Tubes

Chemical composition
(approx. mass % of main components)

 SiO2  B2O3  Na2O + K2O  Al2O3
 81  13  4  2

Chemical resistance of DURAN®

 Water resistance class (DIN ISO 719)   HGB 1
 Acid class (DIN 12 116)  Class S 1
 Alkali class (DIN ISO 695)  Class A 2

Borosilicate glass 3.3 is very resistant to water, neutral and acidic solutions, strong acids and their mixtures and chlorine, bromine, iodine and organic substances. Its chemical resistance properties even exceed the majority of metals and other materials in the case of longer contact times and temperatures greater than 100 °C.

The effects of water and acids only release minor quantities of mainly monovalent ions from the glass. A protective layer of extremely thin, low-porosity silica gel forms during this on the surface of the glass which inhibits further attack. Hydrofluoric acid, phosphoric acid and alkali solutions attack the surface of the glass (relative to concentration and temperature).