Microstructure and stress-induced phase transformation of sol-gel derived zirconia thin films

Zirconium oxide thin films were fabricated using a sol-gel method. The sols were prepared using zirconium alkoxide and acetate. An alcoholic solution of the alkoxide and an aqueous solution of the acetate were dip-coated on a glass substrate and fired at 600 degrees C. Both films were crystallized as the tetragonal phase, which was detected by an XRD and an electron beam diffraction of an ion-thinned section. On the other hand, the electron beam diffraction of the thin section of the film prepared by crushing in a mortar, exhibited the monoclinic phase, which was transformed by stresses applied during sample preparation for TEM. The SEM observation showed a grain size of 30-50 nm. The TEM micrographs exhibited contrasts of less than 10 urn size in a single grain of about 30 nm.