Role of Ionic Depletion in Deposition during Electrophoretic Deposition

Abstract

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 (pHiep) to give coagulation. The variation 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 function of location within the suspension, and the deposition time and its role in the coagulatoin process during EPD.

Electrophoretic deposition (EPD) of hydrous ruthenium oxides with PTFE and their supercapacitor performances

“…This film preparation method is called the electrophoretic deposition, which involves two steps: electrophoresis and deposition. The destabilization and deposition of charged particles near substrate have been explained by several mechanisms as: charge-neutralization of particles by direct electron transfer between charged particles and electrodes; zeta-potential decrease with hydroxide generation by cathodic electrode reactions [14]; pH increase with electrochemical reduction of protons [18]; distortion of the double layer from fluid dynamics and applied electric field [19]; and increase of local particle concentration [15].…”

A study on electrophoretic deposition of Ni nanoparticles on pitted Ni alloy 600 with surface fractality

“…It has been reported [28] that during electrophoretic deposition the zeta potential of the particles in suspension is reduced by the depletion of co-ions in suspension near the specimen surface. Since we consider negatively charged Ni nanoparticles in alkaline ethanol suspension (pH = 10.5) in the present work, OH − and H + are co-ions and counterions, respectively.…”

Electrophoretic Deposition of Pb(Zr, Ti)O3 Powder on Si Wafer: Morphological Change Across Film Thickness

“…On the other hand, the above special morphology evolution during electrophoretic deposition can be explained via DLVO theory. 5 When the charged particles are deposited onto the oppositely charged electrode upon the application of a dc electric field, as shown in Fig. 4, after particle-A is deposited onto the electrode, particle-B receives repulsion from particle-A.…”

“…5,10 In addition, the PZT particles have no reaction with HCl, so we chose HCl as the dispersant of the suspension. Sedimentation experiments Fig.…”