Electrophoretic slip casting

The slip is cast into an electrophoretic mold set-up including a depository 25 and non-depository 28 electrode, wherein the depository electrode makes up less than the entire surface area of the shape- defining element 26 of the mold set- up. Gas formation at the depository electrode is thereby reduced so that porous surfaces in the casting are eliminated or localized. In addition the deleterious interaction of slip hydrolysis and electrode corrosion products is reduced or confined, particularly if the voltage is initially low and later increased. In the fabrication of a U-shaped channel piece 27, the non-depository electrode 28 may be moved from one end of the mold set-up to the other incrementally during casting (fig. 5). In the fabrication of a tube (fig. 6, not shown) a series of electrodes 35 to 42 are contained within the wall of the mold and adjacent pairs of electrodes (forming the anode and cathode respectively) are activated sequentially so that the casting is formed first at the bottom and finally at the top. The casting slip comprises a liquid vehicle, on inorganic powder and, optionally, a deflocculant and has a viscosity of 0.5 to 100,000 centipoises.