An impedance study of the electrophoretic deposition from yttrium silicate suspensions

Yttrium silicate powders were prepared according to a modified Pechini method. The powders were dispersed in isopropanol and the conditions of electrophoretic deposition from these suspensions were optimized. Well adhering coatings were obtained. Impedance spectroscopy was applied to characterize the solvent and the suspension as well as to study the causes for the rapid current decay recorded during constant voltage deposition. Specific conductivity and dielectric constants of solvent and suspension were extracted as well as the resistance of the deposit. Results indicate that mainly mass transport processes through the deposited layer are responsible for the current decay, and to a much lesser extent the resistance of the deposit.