"Non-firing" ceramics have recently attracted much attention in recent years because many functional materials can be achieved by this method without the aid of sintering process. Amorphous silica powder was mechanically treated by a planetary ball mill system, by which the surface of powders was activated and simultaneously particle size reduced extensively. Surface of powders with different milling conditions was investigated by scanning electron microscopy (SEM) and nitrogen adsorption isotherm. The surface activity of raw and treated silica powders was measured based on the water adsorbed volume on the powder surface. Results showed that the powder surface was activated, and the silica powders were pulverized as an effect of ball milling. At milling times as short as 15 min, the powder was rubbed against balls, and the friction between particle/ball breaks the bonds of functional groups like Si-O-Si on the surface of particles. For longer milling times, powders were pulverized and more new active surfaces were formed. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.