Effect of Surface Textures of Steel Sheets on the Crystal Orientation of Electrodeposited Zinc

Abstract

Prior to electrodeposition, the steel sheets were polished with each method such as emery paper, buff and electrolytic polishing, and Zn deposition was performed galvanostatically at 1500 A/m 2 in an agitated sulfate solution at 40 °C to investigate the effect of surface textures of steel sheets on the crystal orientation of Zn. The strain of steel surface and the degree of decrease in grain size of Fe by the strain were largest with emery paper polishing, and were larger in the order with buff polishing, polishing-free, and were smallest with electrolytic polishing. The preferred orientation of the {0001} Zn basal plane of the hcp structure was largest with electrolytic polishing, and was larger in the order with polishing-free, buff polishing, and was smallest with emery paper polishing. That is, the preferred orientation of the {0001} Zn increased with decreasing the strain of steel sheets and increasing the grain size of Fe. With electrolytic polishing, since the strain of steel sheets decreased and the grain size of Fe increased, the epitaxial growth of deposited Zn was easy to occur. The initial Zn deposits seems to grow epitaxially according to the orientation relationship of {111}Fe//{0001}Zn because the preferred orientation of the steel substrate used in this study is {111} Fe. The preferred orientation of the {0001} Zn seems to increase under the conditions where the epitaxial growth of deposited Zn is easy to occur.

Influence of surface roughness on the morphology of interfacial layer and on out-burst formation during hot-dip galvanizing

“…In this study, the surface grains of the matrix were smashed into many small and randomly-oriented crystals upon polishing and the volume of the smashed domain largely decreased when the finer polishing treatment was used. The orientation of the epitaxial Fe 2 Al 5 interfacial layer became random when the surface roughness of the substrate increased [9,13,21]. Besides, the interfacial layers generated on the substrates with the different surface roughness had different sizes, orientation, morphology, thickness, and packing density.…”