THE SYNTHESIS OF METAL HYDROUS OXIDE PARTICLES BY MULTIPHASE ELECTRODISPERSION

A multiphase electrodispersion precipitation reactor called the electr ic dispersion reactor (EDR) was developed to synthesize ultrafine part icles for the production of precursor powders of advanced ceramic mate rials. A pulsed electric field is employed to create dispersions of mi crometer- and submicrometer-scale conducting (aqueous-based) drops in non-conducting (organic) liquids. Species initially dissolved in the o rganic phase diffuse into the aqueous droplets containing the other re agents. Reaction ensues, leading immediately to precipitation and gela tion in the aqueous droplets. The EDR has produced 0.1-5 mum particles of silica, alumina, zirconia, yttria, and composite hydrous oxide par ticles from metal alkoxide and metal salt precursors. Also considered is the application of the EDR to the control and modification of the m orphological characteristics of these particles, with illustrative exa mples.