Preparation and Corrosion Resistance Study of Electrodeposited Ni-TiN Coatings Obtained at Different Magnetic Intensities

In this article, the Ni-TiN coatings deposited on the surface of Q235 steel substrate via a magnetic-assisted electrodeposition approach. The surface morphology, Ti content, phase structure, and corrosion resistance of Ni-TiN coatings were investigated using a scanning electron microscope (SEM), a transmission electron microscopy (TEM), an energy disperse spectroscopy (EDS), an X-ray diffraction (XRD) instrument, and electrochemical workstation facility, respectively. SEM images showed that the surface morphology and thickness value of Ni-TiN coatings prepared at 0.7 T were superior to those obtained at 0.3 T and 1.1 T. EDS and adhesion strength results presented that the Ti content and adhesion strength of Ni-TiN coatings was lower than those produced at 0.7 T and 1.1 T. Meanwhile, Ni-TiN coatings prepared at 0.7 T possessed the highest hardness of 817.3 Hv. XRD patterns exhibited the nickel diffraction peaks of the Ni-TiN coatings fabricated at 0.7 T were broad and low, demonstrating that the size of nickel grain was fine. In comparison to other two Ni-TiN coatings, the one manufactured at 0.7 T possessed a high corrosion potential and a low corrosion current density, illustrating its outstanding corrosion resistance. Corrosion surface morphology revealed that the obvious corrosion pits emerged on the surface of Ni-TiN coatings deposited at 0.3 T, while the obvious corrosion pits were not appeared on the surface of Ni-TiN coatings manufactured at 0.7 T. In addition, the average corrosive weight loss of Ni-TiN coatings prepared at 0.7 T possessed the lowest of 7.2 mg, indicating the excellent corrosion resistance.