Rapid coagulation of silicon carbide slurry via direct coagulation casting

Direct coagulation casting via urease-catalyzed hydrolysis of urea in SiC suspension was studied at room temperature. The results demonstrate that high-solids-loaded SiC slurries with low viscosity can be prepared Lit pH 9.5-10.5. The urease-catalyzed decomposition of urea can be used to shift the pH and to increase the ionic strength of the SiC slurry. The pH value decreased with the increase of coagulation time. The optimal coagulation temperature is 50 degreesC for 62 vol.% SiC slurry. The strength of wet green body after I h of coagulation at room temperature is high enough for demolding and handling without damage in the wet green stage. (C) 2003 Published by Elsevier Ltd and Techna S.r.l.