Influence of Organic Composite Coating Components on Various Properties of 55 percent Al-Zn Alloy Coated Steel Sheet

摘要

The influence of the organic composite coating components on various properties of 55 percent Al-Zn alloy coated steel sheet have been investigated by salt spray test, draw bead test and the measurement of Cr fixation ratio. In addition, the relationship between these properties and the film structure was studied by SAM analysis. The coating, which was composed of newly developed Acrylic resin, phosphate and Cr compound was found to provide good corrosion resistance, formability, good appearance and film insolubility. Further, the results from the film structure analysis show that this coating was characterized by its gradient composition. The layer material in contact with the 55 percent Al-Zn alloy coated steel sheet is an insoluble passivation layer, rich in chromic compounds and phosphate, which provides superior corrosion resistance and film insolubility. The layer material on the outer surface consists primarily of organic resin and is sufficiently flexible to ensure good formability. This new organic composite coating on 55 percent Al-Zn alloy coated steel sheet is commercially produced for building materials applications.