Effects of Ce4+ on the structure and corrosion resistance of electroless deposited Ni-Cu-P coating

In this paper, the effects of Ce4+ concentration on the structure and corrosion resistance of electroless deposited Ni-Cu-P coatings were investigated using microscopy, energy dispersive X-ray spectroscopy (EDX), inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction spectrometer (XRD), polarization curve (PC) and electrochemical impedance spectroscopy (EIS). The results show that the proper addition of Ce4+ can apparently refine the grain size and make the coating surface denser and more uniform, resulting in the enhancement of corrosion resistance of Ni-Cu-P coatings in the flue gas condensate. When the Ce4+ concentration is 8 mg/L, the corrosion current density of Ni-Cu-P coating was reduced by nearly 60% as compared to that prepared without Ce4+ in the bath. However, the excessive addition of Ce4+ can degrade the homogeneity, resulting in the decrease of the corrosion resistance of Ni-Cu-P coatings. (c) 2013 Elsevier B.V. All rights reserved.