Determination of the Morphological Properties of Electroplated Nickel Coatings Obtained Using Impinging Jet Electrode

Ni coatings were produced on copper substrates by using impinging electrolyte jet in Watt Bath at constant temperate. In this study, it was studied the determination of the effects of hydrodynamic parameters of unsubmerged impinging jets on morphological properties of Ni coatings. The electroplating experiments were carried out at constant voltage conditions in order to investigate the effects of jet hydrodynamic parameters which are electrolyte jet velocity (Vj) and dimensionless nozul-to-cathode surface distance (H/d), where H is the distance between the nozul (anode) and the cathode, and d is the nozul inner diameter. It is determined that as these parameters were changed, the current density passed through cathode changed. It was recorded that the change of the current density at cathode changed the morphological properties of produced Ni coatings such as the grain size of Ni coatings, thickness and surface roughness. According to the experimental results, the thickness of Ni coatings increased with increasing Vj and reduced with increasing (H/d) at the jet stagnation point on cathode surface. The grain size of Ni coatings grew with increasing Vj up to 4 m/s. However, it shrinked with increasing Vj up to 8 m/s and with increasing (H/d) values. The surface roughness of Ni coatings reduced with increasing Vj up to 8 m/s and increased with changing (H/d) values from 0.5 to 2.0. (author)