Evolution of Electrochemical Behavior, Electrical Conductivity, and Microhardness of Electrodeposited W Coatings Enhanced by Ni During Long Immersion in 3% NaCl Media

This paper deals with detailed physical and electrochemical properties of electroplated W enhanced by massive Ni coatings. Corrosion behavior of elaborated deposits in 3% NaCl solution is examined, as well as the influence of immersion time in corrosive media on the morphology, electrical conductivity, and microhardness of all coatings. Characterizations are carried out using atomic force microscopy, scanning electronic microscopy, energy dispersive spectroscopy, and X-ray diffraction analysis. The linear polarization curve and EIS during long-term immersion tests were used to identify and quantify corrosion compounds on surfaces. All obtained coatings corrode in the 3% NaCl solution, leading to uniform corrosion for the enhanced W coating, while this is not the case for the pure Ni film. The main corrosion products for the enhanced W coatings are NiO, Ni(OH)(2) and WO3.