A model is developed for deposition during the electrophoretic deposition (
EPD) process. It suggests that ions that move with the charged particles in
suspension are depleted at the depositing electrode, locally changing the
pH toward the isoelectric point (pH(iep)) to give coagulation. The variatio
n of zeta (zeta) potential is modeled via chemical-equilibrium and surface-
adsorption isotherms, The model successfully fits the experimental data for
Al2O3 particles in ethanol when the Freundlich surface-adsorption isotherm
is assumed. Calculations predict the co-ion concentration gradient as a fu
nction of location within the suspension, and the deposition time and its r
ole in the coagulatoin process during EPD.