A Quantitative Analysis of Iron Supersaturation: Iron Distribution in the Zinc Coating and in the Zinc Bath

摘要

In the galvanizing process, dissolution of iron into the iron-saturated zinc bath is a key reaction for quality control and bath management. We analyzed the distribution of iron by the laboratory and the bench scale experiments using the zinc bath with 0.13mass% aluminum at 723-738K, and the reaction time of 1.3-1.5s. It was found that the iron content of Al-Fe inhibition layer formed on the substrate was about 0.03g/m~2, that of Fe-Zn intermetallic layer was 0.17-0.21g/m~2, and the amount of iron released into the bath was 0.11-0.14g/m~2, which made the total amount of iron dissolved to be 0.31 - 0.38g/m~2. We suggest that the Al-Fe inhibition layer may not stop or decrease the iron dissolution, considering the overall distribution of iron.