Preparation and Stabilization of Monoclinic Zirconia by Yttria through Mechanical Alloying

Yttria-stabilized zirconia is a vital material for a variety of high-tech industrial applications. Fully stabilized zirconia is an excellent material for manufacturing of solid electrolyte for solid oxide fuel cell. In the present study, high purity zirconia was successfully synthesized from Egyptian zircon. The produced zirconia was subsequently fully stabilized by 10 mol% yttria via mechanical alloying. Mechanical alloying was conducted in a planetary ball mill with; stainless steel milling assembly, at a rotation speed of 350 rpm, and ball to powder weight ratio of 10. The effect of milling time (up to 32 h) on phase transformation was studied. Characterization of the as prepared zirconia and milled samples was conducted by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray analysis. The obtained results revealed that, the crystal structure of the prepared zirconia is monoclinic. The degree of stabilization and the level of contamination increase gradually with the course of milling. Under the described conditions, the required time for full stabilization was 32 h. The produced powder is nanocrystalline (13.7 nm) with a submicron particle size.