Effect of Aluminum in Zinc on Alloying of Zinc Coating of Galvanized Steel

Abstract

By means of high temperature X-ray diffraction apparatus, was studied the effect of aluminum on the formation of alloy layers during heating of the galvanized steel sheet.
(1) Aluminum additions result in the formation of Fe₂Al₄Zn on the Zn/Fe boundary and shift the formation temperature of the δ₁ phase and Γ phase and the disappearance temperature of the η phase toward the higher side.
(2) Aluminum additions necessary and sufficient for this are 0.12 per cent; greater addition would little affect the phase change.
(3) Fe₂Al₄Zn expands the existence region of the single phase of δ₁ and inhibits the formation of the Γ phase because it interferes with the interdiffusion of iron and zinc.