Electrophoretic deposition infiltration of metallic fabrics with a boehmite sol for the preparation of ductile-phase-toughened ceramic composites

The infiltration of commercially available metallic fibre mats by a boehmite sol using the electrophoretic deposition (EPD) technique was investigated. The nanosized boehmite particles were positively charged in a colloidal suspension at pH 4 and migrated upon application of an electric field to the metallic fabric acting as the negative electrode. Three different type 316L stainless steel fabrics were considered and it was found that the quality of the infiltration depended on the fibre architecture. The EPD parameters, i.e., the applied voltage and deposition time, were optimized for obtaining a high solids loading in between the fibre tows and a firm adherent deposit. The infiltrated fibre mats, being of high quality, i.e., low macroporosity and absence of significant microcracking, serve as prepregs for the manufacture of alumina matrix composites reinforced with a two-or three-dimensional metallic phase. (C) 1998 Chapman & Hall.