The objective of this study was to establish the mechanism(s) controlling degradation of yttria-tetragonally-stabilized zirconia (Y-TZP) powder in aqueous suspensions and determine the significance of this degradation to the aqueous physical chemistry of Y-TZP. Experiments were performed on commercially available Y-TZP powder placed in aqueous suspensions at 25degreesC. Experimental investigations included analysis of the aqueous chemistry of Y-TZP in water via ICP-MS, determination of the surface and bulk structure of the powder via XRD and solid-state NMR, and observation of changes in surface charges via zeta potential determinations. The goal of this study was to control the surface chemistry of Y-TZP in aqueous suspension to promote dispersion and permit aqueous processing of Y-TZP powders.