The influence of two bifunctional aminosilanes, N-(triethoxysilylpropyl)-O-polyethylen oxid urehtan (PEG-silane) and N-(3-triethyoxsilylpropyl) gluconamid (Glucol-silane), on the theological behavior of aqueous zirconia (solid solution with 3 mol% Y2O3) powder slurries and consolidated bodies was investigated. Adsorption of the silanes was determined with viscosity measurements. The influence of tetramethylammonium (TMA) chloride added to dispersed slurries to produce weakly attractive particle networks, formulated with the aminosilane reacted powders was investigated. Bodies were consolidated by filtration at different applied pressures. Viscosity vs shear rate behavior, and consolidated body theology, were determined for slurries formulated at different pH values and different salt contents. The Glucol-silane coated powder had a different isoelectric point (pH approximate to8.5) relative to the unreacted (pH approximate to7.5) and PEG-silane coated powders (pH approximate to7). Dispersed slurries with Newtonian behavior could be formulated for the following conditions: unreacted powder = pH 11, PEG-silane coated powder = pH 10, and Glucol-silane coated powder = pH 6, Bodies with the highest relative density (approximate to 51%) were produced from dispersed slurries (uncoated and coated); their relative density was nearly pressure insensitive, The relative density of consolidated bodies produced from slurries with an attractive particle network (formulated either at the isoelectric point or dispersed with added salt) was pressure sensitive, Bodies consolidated with the weakly attractive particle networks exhibited a critical relative density that separated the body's plastic and brittle behavior. The highest critical relative density (47%) was achieved for bodies consolidated with salt-added, dispersed slurries formulated with the longest aminosilane molecule, which produced the weakest attractive particle network. Bodies that exhibited a claylike flow stress (approximate to0.1 MPa) could be formulated with the shorter aminosilane molecule, whereas the longer aminosilane molecule produced a fluidlike body without a significant yield stress.