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

Abstract

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 ~20%, which increased to ~53% and ~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).