The Evolution of the Electrical Field Drop over the Suspension during EPD

The electrical field drop over a deposit during electrophoretic deposition (EPD) determines the deposition rate and the uniformity of the deposit when a non-uniform electrical field is present. Due to the large practical consequences of a potential drop over the deposit, a procedure was developed to calculate the electrical field strength at the deposition front from currentconductivity measurements during EPD. The evolution of the electrical field strength during EPD was calculated for MEK and ethanol based suspensions. It was found that the suspension composition determines whether a potential drop over the deposit is present or not. EPD experiments on a membrane revealed that the extra potential drop is over the deposit and not caused by electrode polarization for the ethanol-acid based suspensions.