アルミナサスペンションの電気的性質

概要

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Complex impedance, relative permittivity and dielectric loss for the aqueous solutions and 5 vol% alumina suspensions at pH 3.0-10.2 were measured at 17-27°C as a function of frequency of 100 Hz-1 MHz. Their electrical properties were well expressed by a parallel circuit with resistance(R)and capacitance(C). The pH dependence of resistance of solutions and suspensions was associated with the migration of coexisting ions and charged alumina particles, respectively. At the isoelectric point of alumina particles, both the resistivity of solutions and suspensions was comparable because of no migration of flocculated clusters of alumina particles. The capacitance of solutions resulting from the polarization of H_2 O molecules decreased with the increasing conductivity. The effect of coexisting ions on this result was discussed. For the alumina suspensions, deformation of electrical double layer surrounding alumina particles was related to the permittivity. Finally, the time constant(τ=RC)was compared for aqueous solutions and alumina suspensions.
社団法人日本セラミックス協会の論文
1999-04-01