Preparation of Spherical Yttria‐Stabilized Zirconia Powders by Reactive‐Spray Atomization

Abstract

A new inorganic sol–gel process of zirconia (yttri‐stabilized) spherical powders production has been developed. The process is based on spraying zirconia sol into an ammoniawater solution, followed by drying of the gel precipitate and calcination. The gel particles preserve the spherical shape of sprayed droplets, because of a thin solid film that forms on the drop surface via its contact with gaseous ammonia before the impact with the ammonia solution. Being dried and calcined, the gel spheres transform to free–flowing powders composed of the solid, not hollow smooth spheres of zirconia–yttria solid solutions. The particle composition, morphology, and microstructure have been investigated in detail versus the process conditions.