Effects of zinc bath temperature on the coatings of hot-dip galvanizing

The purpose of this work is to identify the influence of zinc bath temperature on the morphology and the thickness of hot-dip galvanizing coating. Hot-dip galvanizing samples were prepared at temperatures in the range of 450–530 °C in steps of 10 °C and at different immersing time. The samples were characterized by using scanning electron microscopy/energy dispersive X-ray analysis. When the galvanizing temperature ranges from 450 to 470 °C, the coating has a coherent and compact ζ layer on the top of a δ layer. ζ phase coexists with liquid zinc pocket around 480 °C. It was found that the coating thickness reaches maximum at 480 °C. When the temperature is above 500 °C, the coating changes to be primarily δ phase.