Investigation of Corrosion Resistance of Ni-P-SiC Composite Coatings After Vacuum Heat Treatment

In this paper, the electroless Ni-P-SiC composite coatings were prepared and the morphology was studied by scanning electron microscopy (SEM). Large number of particles incorporation and uniform distribution were found in Ni-P-SiC composite coatings. Potentiodynamic polarization measurements were made on these composite coatings in 3.5% sodium chloride solution. Though the corrosion resistance of as-deposited composite coatings was better than that of Ni-P coatings, it became inferior in quenched specimens. As a result, the corrosion rate of Ni-P-SiC increased to 0.07013 mmy(-1) (still lower than 0.08367 mmy(-1) of Ni-P coating) after heat treatment at 400 circle C.