Corrosion and hardness studies of electrodeposited Ni–Ag–hBN composite coatings: Effect of hBN content

Abstract Ni–5 wt%Ag–hBN composite coatings are deposited on a copper (Cu) substrate using a conventional electrodeposition technique. The deposition is carried out in an electrolyte bath containing different hBN concentrations. The effect of the hBN content on the surface morphology, hardness, roughness, and wettability are investigated by scanning electron microscopy, Vickers hardness tester, profilometer, and contact angle measurements. This work analyzes and correlates the roughness and wettability with the corrosion characteristics of composite coatings with different hBN content. The corrosion behavior of the composite coatings is examined at room temperature in 3.5 wt%NaCl aqueous solution using potentiodynamic polarization test and electrochemical impedance spectroscopy. The result shows that the composite coatings exhibit smooth and compact morphologies and better corrosion resistance and hardness than the copper substrate. The Ni–5 wt%Ag–hBN coating prepared with 0.2 g/L hBN shows hydrophobic behavior with the highest water contact angle of ∼102°. Depending on the hBN concentrations, the corrosion resistance of the coatings is found to be between 1.80 and 5.46 µA/cm 2 , indicating enhanced resistance to corrosion against pure copper 10.4 µA/cm 2 .