Dispersion and tape casting of silicon carbide through aqueous route

Dispersion behaviour of SiC in aqueous media was studied using four different dispersants and as a function of pH. The slurry was characterized in each case by sedimentation, viscosity and rheological studies. The best dispersant was selected and its optimum amount was determined. For this system, the pH was varied over a range of 2–11. The slurry displayed the minimum viscosity as well as near-Newtonian behavior at pH range 8–11. SiC tapes were obtained by Double doctor blade tape-casting process, with polyvinyl alcohol as binder and PEG and BBP as plastisizers. The stability of the tape casting slurry was determined by rheological characteristics. As-cast tapes were dried in air at room temperature. The results show that it is possible to obtain homogenous defect-free green tapes of 57.7% solid loading and 53% green density with smooth surface using the optimized tape casting slurry. C 2005 Springer Science + Business Media, Inc.