Microstructure and performance of magnetic field assisted, pulse-electrodeposited Ni–TiN thin coatings with various TiN grain sizes

Abstract In this manuscript, Ni–TiN thin coatings were deposited on 45 steel substrate surfaces using a magnetically assisted pulse electrodeposition (MAPE) technique. The surface topographies, chemical compositions, microstructures, microhardnesses, and corrosion properties of the Ni-TiN thin coatings were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), scanning probe microscopy (SPM), triboindenter in-situ nanomechanical testing, as well as corrosion and wear testing. Results indicated that the Ni grain size in the Ni-TiN thin coatings gradually decreased as the grain size of TiN decreased from 180 nm to 32 nm. The mean sizes of TiN nanoparticles and Ni grains in the NT32 thin coating were 41.5 nm and 379.2 nm, respectively. The microhardness of NT180 was the lowest among all three coatings with a mean value of 597.2 HV. Conversely, the mean microhardness of the NT32 thin coating was the highest at 902.9 HV. The size of the TiN particles had a significant effect on the corrosion properties of the Ni-TiN thin coatings, and the corrosion curve of the thin coating of NT32 slowly grew throughout the experiment. Under the same wear test conditions, the NT180 coating showed higher wear mass loss, while the wear mass loss of the NT32 thin coating was the lowest at 36.4 mg.