Preparation and characterization of Nano Ni–TiN coatings deposited by ultrasonic electrodeposition

Nano Ni–TiN coatings were successfully prepared by ultrasonic electrodeposition on the surface of mild steel. The coating microstructure was investigated by scanning electron microscopy, atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The AFM results indicate that moderate ultrasonication led to homogeneous dispersion of TiN particles in the coatings. HRTEM and XRD results demonstrate that the average diameter of Ni grains and TiN particles were approximately 60 nm and 40 nm, respectively. The Ni–TiN nanocoatings greatly improved the microhardness of the substrate. In corrosion tests, Ni–TiN nanocoatings showed better corrosion resistance than Ni coatings, since the presence of TiN particles diminished the interspaces and improved the compactness of the coatings.