Nanostructured Dense ZrO2 Thin Films from Nanoparticles Obtained by Emulsion Precipitation

Nonagglomerated spherical ZrO2 particles of 5–8 nm size were made by emulsion precipitation. Their crystallization and film‐forming characteristics were investigated and compared with nanosized ZrO2 powders obtained by sol–gel precipitation. High‐temperature X‐ray diffraction indicated that the emulsion‐derived particles are amorphous and crystallize at 500°C into tetragonal zirconia, which is stable up to 1000°C. Crystallite growth from 5–20 nm occurred between 500°–900°C. Films of 6–75 nm thickness were made by spreading, spin coating, and controlled deposition techniques and annealed at 500°–600°C. The occurrence of t‐ZrO2 in the emulsion‐precipitated powder is explained by the low degree of agglomeration and the corresponding low coarsening on heating to 500°–800°C, whereas the agglomerated state of the sol–gel precipitate powder favors the occurrence of the monoclinic form of zirconia under similar conditions.