| Zinc has been widely used in steel industry. However, With theprogress of modern science technology, the requirement for corrosionresistance of steel increased significantly. Thin and strong anticorrosion arethe future development orientation. Obviously, Zinc deposit can’t meet therequirements for modern market. Zn-Mg alloy coating has thecharacteristics of high corrosion resistance. So it is the ideal replacementof zinc coating.Pulse current deposition was used to produce Zn-Mg alloy coatingfrom sulfate solution. Polyethylene glycol(PEG) and octadecyldimethylbenzyl (OC) ammonium chloride were used as additives. XRDwas used to analyze the composition and structure. SEM was used toanalyze the morphology. XRF was used to analyze the element content.Electrochemical workstation was used to analyze the corrosion behavior in3.5wt%NaCl solution.The magnesium content of coating reached5.22wt%with pulsecurrent plating, which is7times higher than that with direct current plating.Reverse current could improve the morphology of coating with fewerstomata so that it was more smooth and compact. However, it reduced themagnesium content of coating. Plating solution was more stable withreduction of PEG from3g/L to2g/L. With this condition, smooth andcompact coating was produced without reverse current. Optimalparameters of pulse plating was selected by a orthogonal experiment,which was used to explore the influence of current density, power-on time and power-off time on corrosion resistance. Zn-Mg coating with bestcorrosion resistance was produced with certain condition—I2+=1.2A/cm,ton=5ms and toff=7ms. The corrosion current density equaled to2.8μA/cm2,which was10times smaller than that of zinc plating. |
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