Characterization and corrosion resistance of electrodeposited Ni–Mo–silicate platelet nanocomposite coatings

Nickel–molybdenum–montmorillonite (Ni–Mo–MMT) nanocomposite coatings were prepared by electrodeposition from an alkaline citrate bath containing different concentrations of exfoliated montmorillonite. X-ray diffraction results revealed that the embedding of silicate platelets modified the texture of the Ni–Mo matrix and increased the grain size. Nanoindentation measurements showed increasing microhardness and Youngʹs modulus for the nanocomposite coatings deposited from 1.0 g/L solutions of silicate platelets compared to pure Ni–Mo films. The potentiodynamic polarization and electrochemical impedance measurements showed that the Ni–Mo–MMT nanocomposite layers have higher corrosion resistance in 3.5% NaCl compared to pure Ni–Mo. SEM and AFM micrographs showed a slight increase in the particle size and the surface roughness of the electrodeposited film, respectively as a result of incorporation of MMT particles into the Ni–Mo alloy matrix.