Effect of crystal orientation of steel substrate on the morphology of zinc electrodeposit

The effect of crystal orientation of steel substrate on the morphology of zinc electrodeposit was investigated by using the polycrystal commercial low carbon A1-killed steel sheet and the sulfate bath under the current density of 50-150 A/dm². The morphology of zinc deposit changes according to the crystal orientation of steel sheet,and the morphology can be classified into 3 types by the angle α between the sheet surface plane and the {110} Fe plane. When α is less than about 20°, zinc electrodeposit s grow heteroepitaxially with Burgers' orientation relationship, i.e. (0001) Zn// (110) Fe up to the coating weight of 20g/m²(Type I). When α is between about 20°and 30°,secondary random zinc electrodeposits begin to grow on the initial heteroepitaxial Zn basal plane that follows the Burgers' relationship (Type II). When α is larger than about 30°, Burgers' relationship doesn't meet the case. Flat (0001) Zn plane initially grows parallel to the sheet surface plane, then separate Zn basal planes grow randomly on the initial plane on the slant (Type III).