Reaction between Iron and Solid Zinc through Thin Fe-Al Alloy Layer

Abstract

Fe/FeAl/Zn diffusion couples having a thin Fe-Al alloy layer composed of Fe₂Al₅, FeAl₂ and α phases between Fe and Zn specimens were annealed at 673K for various time. Formation and growth kinetics of Fe-Zn alloy layer were investigated. ζ(FeZn₁₃) phase formed between Zn specimen and the Fe-Al alloy layer after a certain incubation period, the length of which increased with increasing thickness of the Fe-Al alloy layer. The Fe-Al alloy layer was consumed and penetrated by ζ phase and then δ₁(FeZn₇) phase appeared between ζ phase and Fe specimen after disappearance of the Fe-Al alloy layer. It appears that Fe-Zn alloy layer is formed by reaction of Zn atoms with Fe atoms supplied through the Fe-Al alloy layer from Fe specimen.