Corrosion resistance of Ni-based coatings deposited by spray and fuse technique varying oxygen flow

In this work, Ni-based coatings were deposited, at four oxygen flow conditions, on grey cast iron substrates by the spray and fuse technique. The corroded coatings surfaces were studied by scanning electron microscopy (SEM) and their chemical composition was determined by proton induced X-ray emission (PIXE) and Rutherford back scattering spectrometry (RBS) analysis. Using powder X-ray diffraction (XRD) spectrometry the crystallographic structure and properties of the coatings were characterized. The corrosion behavior of the Ni-based coatings and substrate were evaluated by potentiodynamic polarization using a NaCl3.5% solution. The chemical composition in the corrosion areas of the coatings showed that corroded zones are Cl structures. Finally, the study established a relationship between the crystallographic parameters and the corrosion resistance. (C) 2017 Elsevier B.V. All rights reserved.