Mechanochemical Treatment Of Amorphous Silica Powder For Glasses Without Firing

An amorphous silica powder was subjected to mechanical and hydrothermal treatment. Silanol surface groups, which play an active role in the chemical modification of silica, were produced by these two treatments. The surface activity of raw and treated powders was measured as the amount of dissolved Si4+ ion in ammonia (NH3) and potassium hydroxide (KOH) solutions at different concentrations. KOH solution was more effective than NH3 solution in activating the surface of the silica powder. Non-firing glass was successfully fabricated using mechano-chemically treated silica powder. Possible reaction mechanisms of powder surface activation occurring during hydrothermal and condensation processes are also discussed.