PREPARATION OF YTTRIUM STABILIZED ALUMINA -ZIRCONIA DISPERSIONS, BY REACTION IN MOLTEN NITRATE MEDIUM

Preparation of yttrium stabilized alumina-zirconia dispersions, by rea ction in molten nitrate medium. Alumina-zirconia dispersions containin g yttrium are prepared by reaction at 450-degrees-C of zirconium oxych loride, yttrium chloride and a source of aluminium, chloride or nitrat e, with a molten mixture NaNO3 - KNO3. Reactions with aluminium chlori de lead to dispersions containing metal proportions very close to thos e introduced in the molten salt. Yttrium is present both in alumina an d zirconia particles. The latter are stabilized under the tetragonal v ariety. Reactions with aluminium nitrate give solids containing only v ery little proportions of alumina; they are constituted mainly of yttr ium-stabilized zirconia.