The effects of different cooling conditions

such as furnace cooling

air cooling

water cooling in Fe mould

copper plate cooling

on solidification of Zn-4Sb alloy used for hot dip galvanizing spangle have been observed. The results reveal that with the decrease of cooling rate

first eutectic Zn-Sb intermetallic compound particles are converted from laminar into bulk

in which the relationship between size of the particle and cooling rate is approximately accordant to empirical formula:d∝c-12. Meanwhile

the eutectic structure is coarsened and the Zn-Sb intermetallic compound in the eutectic structure is transformed from regular rod into irregular bulky. XRD analysis shows that in the condition of furnace cooling

the Zn-Sb intermetallic compound is β-Sb3Zn4 phase

which is the product of the ζ-Sb2Zn3 eutectoid decomposition

while the decomposition of metastable ζ phase can be restricted in the condition of water and air cooling

and it even totally be restricted in copper plate cooling.