Hydrothermal Preparation of Ultrafme Monoclinic ZrO 2 Powder

Ultrafine powder of single‐phase manoclinic ZrO 2 was prepared by hydrothermal treatments of amorphous hydrated zirconia with 8 wt% KF solution under 100 MPa at 200° to 500°C for 24 h. The process yielded well‐crystallized particles 16 nm and 22 nm in size at 200° and 500°C, respectively .