Effect of Surface Textures of Steel Sheets on the Crystal Orientation Relationship between Zinc and Iron of Electrogalvanized Steel Sheets

To investigate the effect of the surface texture of steel on the crystal orientation relation between Fe and Zn, we deposited Zn at 1500 A・m−2 and 1.48 × 104 C・m−2 onto both Al-killed and IF steel sheets in an agitated sulfate solution at 313 K. Chemically polishing the steel simplifies the deposition of Zn epitaxially because of the decreased strain in the steel surface. For Zn deposited on Al-killed steel, the Burgers' orientation relation of {110}Fe//{0001}Zn was completed after the chemical polishing of the steel. In this case, because the orientation of {111}Fe increased and Zn was deposited according to the orientation relation of {110}Fe//{0001}Zn, the orientation of {0001}Zn decreased. In contrast, for Zn deposited on IF steel, the preferred relation was {111}Fe//{0001}Zn. The crystal-grain size of IF steel is larger than that of Al-killed steel, which makes the epitaxial growth of Zn easier on IF steel than on Al-killed steel. The orientation of {111}Fe was more prominent in IF steel than in Al-killed steel. Because the proportion of {0001}Zn increases under conditions where the epitaxial growth of Zn occurs easily and the orientation {111}Fe was more prominent in IF steel, this appears to be the cause of the relation of {111}Fe//{0001}Zn. The orientation relation between the deposited Zn and steel changes based on the strain, crystal orientation, and grain size of the steel. Therefore, the crystal orientation of the deposited Zn changes as well.