Plasma electroplating Ni coating on pure copper sheet—the effects of H2SO4 concentration on the microstructure and mechanical properties

Nanocrystalline Ni coatings were fabricated by plasma electroplating on pure copper sheets. The influence of H2SO4 concentration of the plating solution on the arc starting voltage and current value was studied. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-Ray diffractometry (XRD) were used to investigate the coating microstructures. The results indicated that the Ni coating prepared in 40–80 g/L H2SO4 solutions had the grain sizes of 50–70 nm. In addition, the maximum values of microharness and coating adhesion were ~ 280 HV and 80 N, respectively. The formation mechanism of Ni coating prepared using different H2SO4 concentration was discussed.