Preparation of Ultrafine Zirconia Particles

Ultrafine ZrO 2 particles have been prepared via a new sol‐gel process. This process involves the addition of excess C 2 H 4 O into the aqueous ZrOCl 2 solution and reacting the mixture at room temperature; a glassy ZrO(OH) 2 gel is formed moments later. An ultrafine ZrO 2 powder is obtained after the gel is dried and calcined; the powder is monoclinic. The average particle size is ∼12 nm, and its specific surface area is 55.1 m 2 /g. In addition, partially stabilized ZrO 2 can be prepared in the same manner, yielding a good result.