Abstract: Shaping of structures is of growing importance so that innovative processes of fabrication are needed. In this sense, electrophoretic deposition (EPD) of local structures from aqueous suspensions on a membrane has proved to be a suitable process. In this work, the electrical field between two point electrodes was simulated employing the finite element method. Different electrode configurations were studied, seeking to attain a strong focusing of the electric field in order to achieve a local deposition. Aqueous suspensions are preferred for industrial application due to the high polarity of water enabling high solid loadings and also for environmental reasons. Nevertheless, the bubbles generating at the point electrodes surface (due to water electrolysis) disturb the electric field. It is therefore very important to minimize the bubbles size. In this respect, we applied a measuring technique to detect and monitor the bubbles formation and first results are presented.
Abstract: Titanate aqueous solution (TTIP-Lac) prepared by direct reaction of titanium tetraisopropoxide (TTIP) with lactic acid (Lac) in water shows characteristics of a polyanion and acts as a dispersant for preparing titanate suspension. Electrophoretic deposition (EPD) of aqueous titania suspensions was investigated with TTIP-Lac as a dispersant and hydroquinone (HQ) as an effective additive for bubble-free EPD of the aqueous system. The oxygen produced electrolytically by the EPD process at basic pH would be consumed by the chemical oxidation of HQ to quinone (Q). Bubble-free titania depositions were fabricated on anodes by EPD. A fired density with 99% theoretical density was obtained.