Investigation of sol-gel derived ZrO2 thin films by nanoindentation

The near surface mechanical response of multi-layer sol-gel derived ZrO2 thin films has been investigated by nanoindentation. Five layer sol-gel coatings deposited on AISI 304 stainless steel were prepared by dip coating and subsequently heat treated at temperatures ranging from 400-700 degreesC. Elastic modulus and hardness were measured at depths corresponding to 7-10 percent of the film thickness. Heat treatment temperature was found to have a significant effect on the resulting near surface hardness and elastic modulus. Film structure was also investigated by cross-sectional transmission electron microscopy and electron diffraction, and was found to transition from an amorphous ZrO2 phase to a combination of cubic and monoclinic phases as heat treatment temperature was increased.