Granulation of Ceramic Powders
Freeze Granulation is today used in manufacturing of various kinds of ceramic products based on functional as well as structural ceramic materials, as monoliths or composites. Typical examples are bioceramics such as zirconia toughened alumina, engineering ceramics based on high-performance powders; oxides such as alumina (Al2O3), zirconia (ZrO2) and silica (SiO2), nitrides such as silicon nitride (Si3N4) and carbides such as silicon carbide (SiC). Basically, all types of ceramic materials can be processed by Freeze Granulation, especially when homogeneous granules, easily crashed at pressing owing to the weak interparticle bonding, are requested for best possible material performance. Besides granules for pressing, Freeze Granulation can also be used as a pre-step prior to preparation of injection molding or extrusion pastes.
By effectively deagglomerate the ceramic powder in a liquid (water or organic solvent) and freeze granulate, the achieved granules can then easily be dispersed into the polymeric substance used in these shaping processes, most often in a higher powder concentration.