ELECTROPHORETIC DEPOSITION OF AL2O3-SIC COMPOSITE

A ceramic composite with Al2O3 particles/SiC whiskers has been prepared by electrophoretic deposition in an isopropanol suspension. In the absence of a small amount of nitric acid (0.06-0.32 M), no deposition is observed. The amount of deposition increases with increasing applied voltage and solid loading, but decreases significantly with the amount of water present. The latter result is attributed to the fact that the colloidal stability of the suspension is degraded by water. Microstructural and compositional analyses show that the SiC whiskers are uniformly distributed in the green compact when the colloidally stable suspension is used during electrophoretic forming.