Nanometer‐Sized ZrO ₂ Particles Prepared by a Sol–Emulsion–Gel Method

Abstract

ZrO 2 powder was prepared by a sol–emulsion–gel method at temperatures below 140°C from ZrO(NO 3 ) 2 · n H 2 O. The asprepared powder was amorphous, but crystallized into the tetragonal structure by 600°C. The metastable tetragonal powder (600°C) was comprised of ultrafine 4‐ to 6‐nm size particles. On heat treatment, the tetragonal form completely transformed into the monoclinic state at 1100°C. Preliminary studies indicate good sinterability with densities greater than 94% at 1100°C and with a grain size of 0.25 μ.