Abstract: The dispersing characteristic of Al_2O_3 powders in suspension was investigated by Zeta potential. The influence of different dispersing conditions, such as different ultrasonic dispersing time, different granularity of Al_2O_3 powders, different dispersant concentration and different pH value of Al_2O_3 powders suspension, on the Zeta potential of Al_2O_3 powders was studied. Results indicate that the absolute value of Zeta potential of Al_2O_3 powders varied with these different dispersing conditions, and there was a best dispersing time range of 4-6 min and a best dispersant concentration of 0.5% while the Al_2O_3 powders dispersed well, and the absolute value of Zeta potential increased with the pH value in alkalescence condition.

Key words: alumina powder%suspension%Zeta potential%dispersion