Characterisation, hardness and corrosion behaviour of electrodeposited ZnFe and ZnFe/BN composite coatings

Abstract

ABSTRACT ZnFe and ZnFe/BN composite coatings were successfully electrodeposited on 304 stainless steel substrates by pulse electrodeposition technique. The effect of various concentrations of BN particles in the plating solution on the structural, hardness and corrosion properties of electrodeposited ZnFe alloy and ZnFe/BN composites were investigated. The deposition process and electrochemical behaviour of alloy and composite coatings were analysed by the Cyclic Voltammetry (CV) method. X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used for the structural, and morphological characterisation of the coatings. Vickers micro hardness indentation was used to determine the hardness of the deposits. The corrosion behaviour of ZnFe alloy and ZnFe/BN composites was investigated by open circuit potential (OCP), Tafel plots, and electrochemical impedance spectroscopy (EIS) methods. As the BN particle content in ZnFe/BN composite coatings rose, the microhardness, and corrosion resistance of coatings increased, which was due to the function of grain refinement and changing dispersion strengthening. Meanwhile, grain sizes were strongly affected from the presence of BN particles and their content. The ZnFe/BN composite coatings with the BN particle concentration of 20 g L−1 had the highest corrosion resistance, and microhardness.