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Hard glass and soft glass distinction Home / What's New / Notice
 

Hard glass (also known as high-borosilicate glass) 95 Glass: SiO2 (80% or so), sodium borate (12%). High temperature, high pressure resistance, corrosion resistance, mechanical strength on the high expansion coefficient, thermal conductivity, and temperature difference changes in operating temperature <783K, annealing temperature 778-833K, a short period of time can be heated to 873K, but even when cooled slowly annealing to reduce the permanent stress. has good processing properties of the flame. many used in the manufacture of beakers, flasks, pressure pipe and complete sets of experimental apparatus. is a corrosion-resistant anti-ion contamination of good materials, such as domestic GG-17, 95 belong to this type of glass material..

Soft glass (also known as ordinary glass) 17 Glass: by component can be divided into sodium-calcium glass (SiO2, CaO, Na2O) and potassium glass (SiO2, CaO, K2O, Al2O3, B2O3). In corrosion resistance, hardness, transparency and loss of sexual penetration of sodium potassium glass is better than glass, but was not so satisfactory in thermal stability. softening temperature low, alkali and strong and not easily lost through suitable lamp flame processing, but should not put too much temperature, commonly used not directly in the manufacture of heating equipment. such as buret, pipet, graduated cylinder, etc., because the expansion coefficient close to Pt, and Pt can be wire seal.
Glass material of the identification methods

Tube-side color
Soft glass was green, yellow rigid glass or white, the color the more light the more hard material, the lighter weight.
Heat
Soft glass: heating to soften soon. If the glass is simultaneously dark aluminum, sodium glass was yellowish flame.
Rigid glass: a short period of time of heating is not softened, the heating time can be softened, to leave the flame on hardened.
Medical penicillin bottles: glass hard
Performance characteristics:
Soft glass containing soluble silicate, has a strong adsorption force, thermal expansion coefficient, temperature mutation easily broken. Therefore made of ordinary glass containers, generally speaking, only for dilution of acid-base solution, titration using.
Rigid glass containing less soluble impurities, thermal expansion coefficient of small, easy to heat treatment. Rigid glassware appropriate for general chemical analysis of major elements. Have commonly used borosilicate glass.

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