Influence of electrostatic interactions in the deposit on the electrical field strength during electrophoretic deposition

A model was developed to explain the magnitude of the potential drop over the deposit for non-conductive powders during electrophoretic deposition (EPD). The magnitude of the potential drop over the deposit is explained in terms of a reduced ion transport through the deposit, as controlled by the pore potential that is related to the thickness of the electrostatic double layer relative to the pore radius and the magnitude of the surface potential of the powder particles. This model was validated for EPD of Al2O3 powder from ethanol-based suspensions with HNO3 addition. The specific resistivity of the deposit could be related to the calculated potential in the pores of the deposit.