Pulse electrodeposition of nano Fe-Ni-Cr/SiC composite coatings from trivalent chromium baths in ultrasonic fields

Nano Fe-Ni-Cr/SiC composite coatings were prepared by using a pulse electrodeposition method from trivalent chromium baths containing a compound carboxylate-urea system and SiC nanoparticles in ultrasonic fields. The influence of pulse electrodeposition and ultrasonic parameters on the SiC and Cr contents in the composite coatings and the coating thickness was investigated, and the effect of ultrasonicwaves on the electrochemical behavior of the composite coatings was analyzed by steady-state polarization curves and cyclic voltammetry (CV) curves. It is indicated that the SiC and Cr contents in the composite coatings and the coating thickness are significantly increased since both ultrasonic waves and pulse electrodeposition are favorable to the deposition of the matrix metals Fe, Ni and Cr. The surface morphology, phase composition and chemical composition of the composite coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The composite coating with a 23.56μm thickness, 4.1% SiC and 25.1% Cr was obtained by this technique. According to the measurements of weight loss and typical potentiodynamic polarization curves, the properties such as anti-wear and corrosion resistance could be improved by increasing the SiC content in the composite coatings.