Solidification structure of Zn-3.5Mg alloy for hot-dipping galvanizing under different cooling conditions

such as furnace cooling

air cooling and water cooling

were observed by SEM （scanning electron microscope）

EDS（energy dispersive spectrum） and XRD （X-ray diffraction）. The results indicate that with the increase of cooling rate

（1） the peritectic reaction of γ-MgZn2 +L→β-Mg2Zn11 of intermetallic compound particles precipitated from the primary eutectic reaction is restrained gradually

resulting in the creation of β-Mg2Zn11 intermetalic compound phase in furnace cooling

γ-MgZn2 phase enwrapped by β-Mg2Zn11 phase in air cooling and γ-MgZn2 phase in water cooling. （2） amount of the equilibrium eutectic phase α-Zn +β-Mg2Zn11 is reduced

while amount of the non-equilibrium eutectic Zn+γ-MgZn2 phase is increased. （3） both the primary eutectic intermetallic compound particles and eutectic structure can be refined. Meanwhile

the width of the particles and eutectic spacing have a certain relation with cooling rate.