An advanced fabrication route for alkali silicate glass by non-firing process

Abstract

An amorphous silica powder surface was treated separately and combining mechanical and chemical treatment processes. The raw silica powder was mechanically modified using a planetary type mill at a rotation speed of 200rpm for 15min using a 5mm size ball. The raw and the mechanically modified silica powders were hydrothermally treated for 5, 15 and 24h lengths of time. Silanol surface groups successfully produced by the treatments were measured by diffuse reflectance infrared fourier transform (DRIFT) spectroscopy. The results show that the combination of mechanical and chemical, so call mechanochemical treatment, is the most efficient in enhancing the quantity of surface silanol groups. The mechanochemically treated powder was used for the fabrication of glass. Silica glasses were successfully fabricated without firing by mixing the treated powders with KOH 5M solutions. Morphology and transparency of the obtained glasses were analyzed using SEM and UV–VIS–NIR techniques. Possible mechanism reactions of powder surface activation occurring during the mechanochemical and condensation processes are also discussed.