Application of alginate gelation to aqueous tape casting technology

This work deals with a novel forming process for manufacturing ceramic tapes in an aqueous medium, that combines tape casting and gel-casting technologies. Aqueous tape casting suspensions of Al2O3 are prepared to a solid loading of 57 vol.% (84 wt.%) by adding 15 wt.% of a binder system consisting of acrylic emulsions and a small concentration (≤0.5 wt.%) of alginate. The as-cast tape is immersed in a CaCl2 solution and the alginate undergoes gelation. This allows releasing of the tape from the carrier film so that no sticking occurs and crack formation is avoided. Sintered densities are ∼97% of theoretical, similar to those obtained by conventional aqueous tape casting.