Crystallographically-Oriented Macropores in Multi-Crystalline Zn

This paper presents the self-organized growth of crystallographically-oriented macropores in multicrystalline Zn sheets by pulsed-potential electrochemical etching in an environmentally friendly aqueous KCl electrolyte. The resulting pores show very high similarity to crystallographically-oriented pores found in III-V semiconductors with respect to branching and intersection of pores. In contrast to pores in other metals like Ti with amorphous TiO2 pore walls, the pore walls in Zn entirely consist of metallic Zn. These pores in multicrystalline Zn are perfectly suitable for mechanical interlocking with polymers since the pores grow under various angles to the sheet surface. All pores grow in directions with side branching pores in [-12-10] and in [1-210] direction allowing for a good mechanical interlocking to polymers, i.e. they act perfectly as hooks forming a rigid connection between the Zn sheet and the polymer solving the well-known problem of poor adhesion of polymers and paint on Zn surfaces.