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 bo ehmite sol using the electrophoretic deposition (EPD) technique was in vestigated. The nanosized boehmite particles were positively charged i n a colloidal suspension at pH 4 and migrated upon application of an e lectric 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 fib re architecture. The EPD parameters, i.e., the applied voltage and dep osition time, were optimized for obtaining a high solids loading in be tween the fibre tows and a firm adherent deposit. The infiltrated fibr e mats, being of high quality, i.e., low macroporosity and absence of significant microcracking, serve as prepregs for the manufacture of al umina matrix composites reinforced with a two-or three-dimensional met allic phase. (C) 1998 Chapman & Hall.