Zirconia Coating on Stainless Steel Sheets from Organozirconium Compounds

The stability and the coating characteristics of a variety of organozirconium compounds have been investigated to coat ZrO₂ films on stainless steets for the improvement of heat resistance against oxidation. Zirconium tetraoctylate and zirconium tetrakis(acetylacetonate) were found to be more stable than zirconium alkoxides in an ambient atmosphere. The ZrO₂ films from zirconium alkoxides became white and discontinuous when the thickness of the films exceeded about 200 Å (20 nm). On the other hand, transparent ZrO₂ films were obtained from zirconium tetraoctylate and zirconium tetrakis(acetylacetonate). The IR spectra of the films showed that the heat treatment at 400°C for 5 min produced organic-free ZrO₂ films. The heat resistance of stainless steel sheets against oxidation was improved by the ZrO₂ coating, depending on the film thickness.