Effect of Al Content on the Structure of Thin Oxide Films on the Hot-Dipped Zn-Al Coated Steel Sheets
Katsuhiro NISHIHARA, Masanari KIMOTO, Takeo KUDO, Hitoshi UCHIDA, Yuichi HARUYAMA, Kazuhiro KANDA and Shinji MATSUI
Abstract:Electronic structures of oxide films on hot-dipped Zn-0.2%Al, Zn-5%Al, and Zn-55%Al coated steel sheets have been investigated by means of the synchrotron radiation photoemission spectroscopy and compared with those of Zn and Al pure metal sheets. The oxide films were prepared by 85 hour exposure in air saturated with water vapor at 323K. The oxide film on Zn-0.2%Al had the same photoemission spectrum as the pure Zn metal, while Zn-5%Al and Zn-55%Al were similar to the pure Al in the form of photoemission spectrum. It was found that the electronic structure of the oxide films and the depth profile of the ratio of zinc oxide to aluminum oxide are varied with the ratio of Zn to Al in the alloys. The corrosion resistance of Zn-Al alloys is discussed being related to the electronic structure of the oxide films. Key Words:Zn-Al, Hot-dipped, Oxide, Corrosion, Electronic structure, Photoemission, Synchrotron