Temperature induced forming: Application of bridging flocculation to near-net shape production of ceramic parts

The use of a molecular dispersant (tri-ammonium citrate) and a polymer (pol y (acrylic acid)) is described for the water-based colloidal powder process ing of alpha-alumina in order to form green parts by temperature-induced fl occulation. The underlying gelation mechanism is proposed to relate to the exchange of the molecular dispersant for the polyelectrolyte in conjunction with the solubility of alumina in aqueous media. In this way, near-net sha pe ceramic parts with oxide surface characteristics can be simply fabricate d by heating slurries with high solids content in a mold from room temperat ure to 60 degrees C. This method shows promise for technical application un der the concept of Temperature Induced Forming (TIF).