| Summary: | 碩士 === 中國文化大學 === 材料科學與製造研究所 === 89 === This research aims to investigate the influence of pH values to the dispersion and rheological behavior of alumina powder suspensions, and to the particle-packing structure of electrophoretically deposited（EPD）alumina ceramic membranes. The powders used include nano-Al2O3 and AKP-50 Al2O3, in pH values of 2 and 11, and the powder mixtures were ball-milled in aqueous system over a concentration range 1-15 wt% of the alumina solids loading. The dispersion, rheological behavior and the related stabilization mechanisms of the aqueous suspensions were experimently in vestigated.
Our experiment reveals that the solution pH is critical to the suspension stability. The suspension stability in acid is better than that at the basic condition. In the rheological measurement, the viscosity increases as the solids loading increases. The suspension viscosity at pH11 is higher than at pH2 over given shear-rate investigated（1-1000sec-1）. The alumina suspension shows shear-thinning behavior at low shear rate（1-100sec-1） and shear-thickening behavior at high shear rate（100-1000sec-1）.
In the EPD processing, the thickness and deposited weight of alumina were increased as the EPD time increasing. The consolidated films show significant grain growth after sintering at 1100℃.
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