Influence of laser surface structuring of steel sheets on the mechanical properties of electrodeposited ZnNi coatings

The influence of laser surface structuring on the formation and the internal strength of electrodeposited ZnNi coatings on steel sheets was investigated. Surface structuring by extended direct laser interference patterning (xDLIP) was used to modify the cohesive strength in the ZnNi layer. An SEM analysis of the crystal structures shows perpendicular nucleation during ZnNi layer formation and areas of crosslinked crystalline structures, which results in an interlocking of crystal structures within the layer. The interlocked crystalline structure leads to an increase of the cohesive strength in the ZnNi layer, which was observed in roller peel tests according to DIN 1464 for adhesively bonded joints.