Structure and Electrochemical Characterization of Ni+W+Si Composite Coatings in an Alkaline Solution

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Ni+W+Si composite coatings were prepared by nickel deposition from a bath containing suspension of tungsten and silicon powders. These coatings were obtained under galvanostatic conditions, at the current density of jdep. = 0.100 A cm-2 and at the temperature of 338 K. A scanning electron microscope was used for surface morphology characterization of the coatings. Chemical composition of the coatings was determined by EDS method and phase composition investigations were conducted by X-ray diffraction. Thermal treatment of obtained coatings was conducted in the air and nitrogen atmosphere. Electrochemical corrosion resistance investigations were carried out in the 5 M KOH, using potentiodynamic method. It was found that Ni+W+Si coatings after thermal treatment in the air are more corrosion resistant in alkaline solution than Ni+W+Si coatings after thermal treatment in the nitrogen atmosphere and as-deposited coatings. The main reason of this is presence of new phases, in particular NiWO4 and SiO2.

Info:

Periodical:

Materials Science Forum (Volumes 587-588)

Edited by:

António Torres Marques, António Fernando Silva, António Paulo Monteiro Baptista, Carlos Sá, Fernando Jorge Lino Alves, Luís Filipe Malheiros and Manuel Vieira

Pages:

815-819

DOI:

10.4028/www.scientific.net/MSF.587-588.815

Citation:

M. Popczyk et al., "Structure and Electrochemical Characterization of Ni+W+Si Composite Coatings in an Alkaline Solution", Materials Science Forum, Vols. 587-588, pp. 815-819, 2008

Online since:

June 2008

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$35.00

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