Microstructure and corrosion resistance for the electrodeposited nickel from watts-type baths

摘要

Electrodeposition processes using direct current (DC) require the use of additives to control deposit structure and properties as well as current distribution. This work presents a study on the influence of electrodeposited nickel prepared from a Watts bath at different current density ranging from 1 Adm~(-2) to 10 Adm~(-2) at pH = 4. The structure of the nickel layers was investigated by scanning electron microscopy (SEM). Vickers hardness of deposited layers was also investigated. The electrochemical behaviour of the nickel layers was investigated by polarization potentiodynamic and electrochemical impedance spectroscopy methods. Protection level against corrosion was evaluated by polarization curves and Electrochemical Impedance Spectroscopy (EIS). Important results include the formation of uniform deposits showing fine grain and excellent protection against corrosion.