Electrophoretic Method for Fabricating Porous Ceramics – Application to Different Oxide Materials

Abstract

Electrophoretic deposition (EPD) with controlled gas evolution by electrolysis was used for producing ceramic green bodies with unidirectional pore channels. The method was applied to alumina, alumina-toughened zirconia, and mullite. It requires stable aqueous suspensions with sufficiently high particle charge for the electrophoresis and appropriate amounts of electrolyte for the gas bubble formation. An anionic polyelectrolyte and ammonia were shown to be a suitable additive combination for all three oxide powders. The amount of polyelectrolyte was chosen for each of the powders on the basis of electroacoustic measurements of the zeta potential. The addition of ammonia solution was necessary in order to obtain the desired porous structures.