THE CORROSION BEHAVIOR OF ELECTROLESS Ni-P-SiC NANO-COMPOSITE COATING

Abstract

Composite coatings constitute a new class of materials which are mostly used for mechanical and tribological applications. The corrosion resistance of these composite coatings, however, has not been systematically studied and compared. In this study, electroless Ni – P composite coatings are formed on St 37 steel through the addition of nano-scale SiC particles to the plating bath. This work aimed to investigate the corrosion characteristics of electroless nickel composite coatings using electrochemical measurements which include polarization and electrochemical impedance spectroscopy tests. The morphology and structure of the composite coatings were studied by scanning electron microscopy (SEM), energy dispersive spectrum (EDS) and X-ray diffraction (XRD). The results showed that both electroless nickel and electroless nickel composite coatings demonstrated significant improvement of corrosion resistance in salty atmosphere.