Corrosion resistance of nickel-coated SiCp/Al composites in 0.05 M NaCl solution

The SiC_p/Al composites was modified by electroless nickel plating, the corrosion behavior of Ni-coated SiC_p/Al composites in 0.05 M NaCl solution was investigated by situ electrochemical techniques. The surface properties of the Ni-coated SiC_p/Al composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectrometer (EDS). The results showed that: The Ni-P layer is the most uniform with a thickness of 15 μm after electroless nickel plating for 60 min; Soak in 0.05 M NaCl solution, Ni-coated SiC_p/Al composites exhibits higher corrosion potential and impedance values than non-coated SiC_p/Al composite, showed that a greater corrosion resistance of Ni-coated SiC_p/Al composite, and the corrosion resistance of SiC_p/Al composite is the best after 60 min nickel plating. The Scanning Electrochemical Microscopy (SECM) measurements showed that the formation of the corrosion-resistant passive film in the Ni-coated SiC_p/Al composites are easier, and the main corrosion mechanism of composites is local corrosion. The nickel phosphorus compound is easily produced on the surface of Ni-coated SiCp/Al composites after polarizing 1 h, which inhibits the corrosion of the composite. Thus, the Ni-coated SiC_p/Al composite has greater corrosion resistance in a chloride-containing environment than the SiC_p/Al composite.