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COMPARISON OF ELECTRODEPOSITION ASPECTS AND CHARACTERISTICS OFNi-WAND Co-WALLOYNANOCRYSTALLINE COATINGS
Z. Ghaferi, K. Raeissi, M. A. Golozar,, A. Saatchi, S. Kabi,
Volume 7, Issue 4 (10-2010)
Abstract

Abstract:

current densities. Electrochemical impedance spectroscopy (EIS) results showed that the codeposition mechanism of

tungsten in Ni-W deposition is the reduction of tungsten oxide which changed to the reduction of tungsten-containing

ion complexes at higher current densities. In Co-W electrodeposition, the tungsten codeposition takes place via

reduction of tungsten oxide, although, the role of tungsten-containing complexes at higher current densities cannot be

ruled out. The surface morphology of Ni-W coatings was crack-free and was strongly dependent on deposition current

density. In addition, higher grain size and lower tungsten content were obtained by increasing the current density. In

Co-W coatings, no obvious variation in surface morphology was observed except for the fine cracks appeared at

higher current densities. In this system the grain size remained almost constant with increasing current density. The

microhardness values of Ni-W and Co-W coatings decreased due to the increase in the grain size and/or decrease in

tungsten content.

Ni-W and Co-W alloy nanocrystalline coatings were electrodeposited on copper substrate at different
Synthesis and Characterizations of Ni-W alloy
Dipali Potdar, Sushant Patil, Yugen Kulkarni, Niketa Pawar, Shivaji Sadale, Prashant Chikode,
Volume 21, Issue 1 (3-2024)
Abstract
The Nickel tungsten (Ni-W) alloy was electrodeposited on stainless steel (SS) substrate using potentiostatic mode at room temperature. Potentiostatic electrodeposition was carried out by varying the deposition time. The physicochemical properties of Ni-W alloys were studied using X-Ray diffraction (XRD), Electron Microscopy and micro-Raman spectroscopy. Recorded XRD spectra was compared with standard JCPDS card and the presence of Ni was confirmed, no such peaks for W were observed. Further study was extended for micro-Raman analysis. From Raman spectroscopy study the appearance of Ni-O and W6+=O bonds confirms that the Ni-W present in amorphous phase. Several cracks were observed in SEM images along with nanoparticles distributed over the electrode surface. The appearance of cracks may be correlated with the in-plane tensile stresses, lattice strains and stacking faults and may be related to the substrate confinements.
 
Investigating the Effect of Current Density on Electrodeposited Ni-TiC-WC Composite Coating and Evaluating the Corrosion Resistance of the Coating and Substrate in NaCl Solution
Ali Keramatian, Mohammad Hossein Enayati, Fatemehsadat Sayyedan, Sima Torkian,
Volume 22, Issue 2 (6-2025)
Abstract
The aim of this study was to investigate the effect of current density on the microstructure of electrodeposited Ni–WC–TiC composite coatings on 304 stainless steel and compare the corrosion resistance of the coating and substrate in a 3.5 wt.% sodium chloride solution. A Watts nickel bath was employed under direct current (DC) conditions. Microstructure, elemental composition, and phase composition analyses were conducted using scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results revealed that the coating formed at a current density of 40 mA/cm² exhibited a denser microstructure with higher cohesion and uniformity compared to coatings produced at other current densities. The corrosion resistance of the coating and substrate was evaluated using Tafel and electrochemical impedance spectroscopy (EIS) analyses. The corrosion test results indicated that the substrate exhibited superior corrosion resistance compared to the coating. Based on the dynamic polarization test plots, the corrosion mechanism of the substrate is active-quasi passive, with a pseudo-passive layer forming on the sample which remains stable within the potential range of -0.17 to 0.17 V. Beyond this potential range, the sample becomes susceptible to pitting. In the coated sample, the corrosion behavior is similar to that of the substrate, with the exception that the pseudo-passive layer remains stable within a narrower potential range of -0.19 to 0.08 V.
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