Performance of Pulse Electrodeposited Nanocrystalline Ni-W-Cr-Nd Alloy Coating

Four kinds of nanocrystalline Ni-W-Cr-Nd alloy coatings with different tungsten contents,as substitutes for chromium coating,were successfully obtained by pulse electrodeposition.The surface morphology,composition and phase structure of as-deposited alloy coatings were analyzed by means of scanning electron microscopy,energy dispersive spectrometry and X-ray diffraction.The corrosion resistance of the alloy coatings was evaluated using potentiodynamic scan technique and electrochemical impedance spectroscopy.It was found that as-deposited Ni-W-Cr-Nd alloy coatings were dense and uniform,and had no cracks.Grain sizes of the alloy coatings with 22%,26%,31%,36% W were 14,17,21,26 nm respectively.Particularly,the alloy coating with 22% W possessed better high-temperature oxidation resistance and corrosion resistance than Cr coating,and the alloy coating heat-treated at 400 ℃ had a high hardness of 1 132 HV and good wear resistance,showing a small wear rate of 0.018 3 mg/(cm2·h).