KINETICS STUDY AND MECHANISM OF ELECTROPHORETIC DEPOSITION: A NEW INSIGHT BY SIGNAL/NOISE ANALYSIS

Abstract

Kinetics of electrophoretic deposition (EPD) has been thoroughly investigated using equivalent circuit modeling in this paper. The aim of this work is the better understanding of the EPD mechanism. In this case, mass deposition in EPD was modeled as charging of the reservoir in an RC circuit. Accordingly, the weight–time ([Formula: see text]–[Formula: see text]) curves of EPD were regarded equivalent to the [Formula: see text]–[Formula: see text] curves of a reservoir. It was found out that the rate of deposition depends not only on the specific resistivity but also on the permittivity of the suspension. Furthermore, the mechanism of EPD was studied using large- and small-signal analyses conducted by the Simulink modeling toolbox of MATLAB software. In this case, the frequency of sinusoidal waves was equivalent to the probability of collision of particles. Results show that there is an alternative sinusoidal-like noise on the main signal of [Formula: see text]–[Formula: see text] curves. It predicts that charged particles move toward the opposite electrode during the EPD process and accumulate next to the electrode for losing their ionic power. Ultimately, the accumulated particles (including several particles not owing ionic power) depose on the electrode at once. The time which is needed for particles to decrease their ionic power is a delay (relaxation) time of the deposition process.