Aluminum nitride (AlN) reinforced electrodeposited Ni-B nanocomposite coatings

Ni-B nanocomposite coatings containing various concentration aluminum nitride (AlN) nanoparticles (NPs) were developed through a scalable and conventional electrodeposition process. The influence of addition of AlN nanoparticles (0.6 and 1.2 g L-1) on the morphological, mechanical and corrosion protection efficiency of Ni-B nanocomposite coatings was explored using SEM, XPS, XRD, AFM and electrochemical techniques. The incorporation of AlN nanospecies into the Ni-B matrix coating decreased the porosity of the cauliflower-like structure and improved the mechanical properties including hardness and wear. The mechanism of electrochemical co-deposition was proposed. The potentiodynamic analysis exhibited that the protection efficiency (PE%) of Ni-B coating is similar to 20%, which increased to similar to 53% and similar to 73% by addition of AlN nanoparticles of 0.6 and 1.2 g L-1, respectively. The corrosion resistance could be credited to the presence of inactive and insulating AlN nanoparticles that filled the existing defects in Ni-B matrix and subsequently decreased the active area exposed to the corrosive electrolyte (3.5 wt.% NaCl).