This paper describes a novel colloidal route for the preparation of hollow
mullite ceramic microspheres with sizes in the range of 10 μm. An emulsion
technique was combined with a water extraction sol-gel process, to form an
aqueous droplet dispersion and gel the resulting droplets by extracting
water with a dehydrating liquid. The liquid-filled gelled microcapsules were
then dried and fired to form hollow ceramic microspheres. Important
processing variables controlling the microspherc morphology were determined
and a formation mechanism was proposed. Due to its potential applications in
microelectronic packaging, mullite was selected as the model material for
the present work, but the synthesis technique may be used for making other
single or multiphase ceramic compositions