Production of NiW-ANC as Anticorrosion and Erosion Coatings in Petrochemical Industries

Ni-W nanocomposites electrodeposited from tartrate solution consist of three different phases, which are all present in high W-content nanocomposites: a solid solution of W in a Ni matrix; an intermetallic compound Ni4W, as well as another solid solution of W in Ni with a W content higher than 20 mol. %. RAMAN and XRD analysis revealed that the nanocomposites were covered with a surface layer of complex structure containing the pure metals Ni and W. Corrosion of Ni-W nanocomposites in sulfuric acid solution at OCP, occurs by the preferential dissolution of nickel from the surface layer. The longer the corrosion process lasts, the more the surface behaves like pure W. The lowest initial corrosion rates were recorded with nanocomposites rich in W, but after aging at OCP the lowest corrosion c.d. was found for the nanocomposite with the most homogenous phase structure, consisting of the solid solutiononly.

Keywords:

nickel-tungsten , induced codeposition , phase structure , corrosion