CORROSION BEHAVIORS OF HOT-DIP GALVANIZING COATING IN SEWAGE

The corrosion behaviors of hot-dip galvanizing coating were studied by using polarization curve technique,electrochemical impedance spectroscopy(EIS),scanning electron microscopy(SEM) and X-ray diffraction(XRD).The corrosion medium was the sewage collected from the city of Zunyi.The corrosion rate of hot-dip galvanizing coating in the flowing sewage was faster than that in the static sewage.The corrosion rate of hot-dip galvanizing coating with a hole was faster than that without a hole.When the time was prolonged,the polarization resistance increased and the corrosion current decreased.There were some white oxides of zinc and some corrosion pits in the surface corrosion products.