VIBRAFORMING AND IN-SITU FLOCCULATION OF CONSOLIDATED, COAGULATED, ALUMINA SLURRIES

Aqueous, alumina slurries dispersed at low pH form weakly attractive networks when excess counterions are added, These slurries can be consolidated to a high relative packing density via either pressure filtration or centrifugation without mass segregation or density gradients, These saturated, consolidated bodies can be reshaped by vibrating them into a complex-shaped die cavity, a process termed VibraForming, The yield stress of these bodies can be increased by adding urea to the slurry before consolidation and then heating the VibraFormed body to change the pH of the water within the body to the isoelectric point for the alumina powder, The increased yield stress, characterized by stress relaxation experiments, allows the body to be removed from the die cavity without shape distortion.