An Experimental Study of the Liquid Domain of the Zn-Fe-Al-Mn Quaternary System at 460 ℃

摘要

The liquid domain of the Zn-Fe-Al-Mn quaternary system at 460 ℃ was experimentally investigated. The nature of relevant intermetallic compounds was studied using scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS). A total of 12 Fe-oversaturated baths with various Mn additions was prepared for the study. When the Al addition was fixed at 0.14 wt.%, δ-FeZn_(10) and δ-MnZn_9 were found to co-exist with the liquid phase at low Mn additions. Increasing Mn additions above 1.3 wt.% greatly stabilized δ-MnZn_9 so that it became the sole compound existing in the liquid phase. When the Al addition was fixed at either 0.16 or 0.27 wt.%, η-Fe_2Al_5 was found at low Mn additions but ceased to exist as Mn additions increased above 0.8 wt.%. The current study indicates that the addition of Mn to the bath promotes the formation of δ phases, thus shifting the invariant point of δ/η in the Zn-Fe-Al ternary system to a higher Al level. Based on experimental results, the liquidus surfaces in the Zn-rich corner of the quaternary system at 460 ℃ were schematically constructed, and implications for practical galvanizing operations were suggested.