To investigate the method of estimating the degree of dispersion and stability of a dispersed system, the frequency responses of AC-impedance were measured using ground SiO
2, TiO
2 and Al
2O
3 powders.
It was found that the electric equivalent circuit of the dispersed system was a parallel circuit made up of a resister and capacitor. Its AC-impedance was dominated by the concentration of the dissociation ion on the surface layer of the powders.
From the measurement of the AC-impedance and of the concentration of the dissociation ions in the dispersed system with increasing specific surface area of grinding powders, it was found that for the SiO
2-CH
3OH and TiO
2-CH
3OH systems, the AC-impedance and the concentration of the dissociation ions, H
+ showed an interesting tendency. For the Al
2O
3-CH
3OH systems, the AC-impedance tended to decrease while the concentration of the dissociation ions, OH
- showed an interesting tendency.
The AC-impedance of the dispered system was closely related to the concentration of the dissociation ion on the surface layer of powders.
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