MOCVD of thick YSZ coatings using acetylacetonates

Thick (up to 20 μm) coatings of yttria-stabilized zirconia with columnar structure have been grown by thermal MOCVD at 630-820 °C using acetylacetonates of Zr and Y as precursors. The samples have been characterized by Scanning Electron Microscopy (SEM), Wave Dispersion X-ray Analysis (WDX) and X-ray Diffraction (XRD) to find out the interplay of deposition conditions with coating microstructure, yttria content and phase composition. In particular, it has been found that homogenous nucleation reactions in gas phase at high temperature lead to the decrease of total growth rate and enrichment of resulting coating with yttrium. It has also been found that heterovalent substitution in ZrO2 leads to remarkable increase of a column width and a coating integrity. A simple model for the quantitative description of the process is presented.