Microstructure and corrosion behavior of electrodeposited Ni-based nanocomposite coatings reinforced with Ni60Cr10Ta10P16B4 metallic glass particles

Ni-based nanocomposite coatings reinforced with Ni60Cr10Ta10P16B4 metallic glass powders have been successfully deposited by a direct current electrodeposition method in a typical Watt's bath. The effect of the glassy particles content on the microstructure, micro-hardness and corrosion behavior of the coatings have been evaluated. The structural investigations have been conducted by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion behavior of the coatings has been investigated in a 3.5 wt % NaCl solution by a potentiostat-galvanostat device in the potentiodynamic polarization mode. The composite coatings with the negligible amounts of porosity and crack, homogeneous distribution of the glassy particles, and appropriate bonding at the matrix/reinforcement interface are obtained. The results demonstrate that the crystallographic texture and surface morphology of the coatings are significantly changed by the addition of the glassy particles into the bath. A minimum matrix crystallite size of 31 nm and maximum glassy particles incorporation of about 6.4 vol% are obtained for the particles concentration of 10 g/L in the deposition bath. The microhardness of the coating is enhanced with increasing the content of the reinforcing particles in the bath and reaches a maximum value of 475 HV for the particles concentration of 10 g/L. Moreover, the corrosion current density and corrosion rate are significantly reduced from 2.25 mA/cm(2) and 0.958 MPY for the pure Ni coating to 0.05 mA/cm(2) and 0.021 MPY for the nanocomposite coating. (C) 2017 Elsevier B.V. All rights reserved.