Effect of salicylaldehyde on microstructure and corrosion resistance of electrodeposited nanocrystalline Ni–W alloy coatings

• Effect of salicylaldehyde (0–500 ppm) on Ni–W alloy coatings has been studied.
• Deposits obtained from optimized bath (100 ppm) showed good corrosion resistance.
• Inclusion of additive resulted in low surface roughness and reduced grain size.

In this paper, nanocrystalline Ni–W alloy coatings were deposited from citrate bath containing salicylaldehyde (0–500 ppm). The structure, microstructure and surface roughness of coatings were separately analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscopy (AFM). The corrosion resistance of the Ni–W alloy coated specimens was evaluated using potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy (EIS) studies. Results indicated that electrodeposits obtained in the presence of additive (100 ppm) in the bath were, nanocrystalline, uniform and smooth in their texture. A low value (7.02 μA/cm2) of corrosion current and high value (1666.90 Ω cm2) of charge transfer resistance supports for its superior corrosion resistance property. The inclusion of additive in the deposit was evidenced by FT-IR spectra.