Evaluation of Corrosion Prevention of Zinc-Iron Compound Phases and Iron-Zinc Solid Solution on Galvannealed Steel Sheets

Abstract

The corrosion resistance of the δ₁ phase （Zn-Fe compound） coated on galvannealed steel sheets （GA） and the Γ phase （Zn-Fe compound）, α solid solution （Fe-Zn solid solution）, which were formed by heating GA, was investigated using combined cyclic corrosion test, polarization measurements and structure analyses. The results suggest that the α solid solution, Γ and δ₁ phases have relatively good corrosion resistance in order, and these coating phases have sacrificial corrosion protection against base steel. It was also considered that the corrosion prevention of α solid solution will decrease when the exposed area of the base steel becomes large.