SLIP CASTING OF SIC-SIALON COMPOSITES

SiC-SiAlON composites were prepared by the reaction sintering of SiC, kaolin and silicon mixtures in a nitrogen atmosphere. To form complex shapes, slip casting was used, with water preferred as an economic dis persion medium. The methodology to obtain a highly concentrated, well- dispersed, slurry (73% by weight of dry matter) is described. Zeta pot ential and complementary redox potential measurements revealed the nat ure of the surface species as a function of pH and indicated compatibl e conditions for the three constituents (kaolin, SiC, Si). Sodium meta -silicate was used as deflocculant and CMC as organic binder. (C) 1997 Elsevier Science Limited.