Sol-gel synthesis of yttria stabilized zirconia membranes through controlled hydrolysis of zirconium alkoxide

Yttria stabilized zirconia (YSZ) polymeric sols were synthesized by control led hydrolysis and condensation of zirconium tetra-n-propoxide. Yttrium nit rate was added before hydrolysis as the source of yttria. Acetylacetone was used as chelating ligand to modify the reaction rate of zirconium alkoxide . The dependence of YSZ sol formation as well as gelation time was investig ated experimentally on the contents of acetylacetone, n-propanol (solvent) and water for hydrolysis. With a stable sol, YSZ membranes were prepared on porous alpha-alumina supports by a dip-coating process. The membranes were characterized by scanning electron microscopy and gas permeability testing . Unsupported YSZ membranes were also prepared with the same sol, and were investigated with isothermal nitrogen adsorption/desorption porosimetry and X-ray diffraction. The results show that YSZ membranes with nanosize pores were successfully prepared by the sol-gel technique with the polymeric sol s. (C) 1999 Elsevier Science B.V. All rights reserved.