Al2O3/Si3N4 nanocomposite coating on aluminum alloy by the anodizing route: Fabrication, characterization, mechanical properties and electrochemical behavior

Abstract An Al 2 O 3 /Si 3 N 4 nanocomposite coating was successfully fabricated on commercial aluminum alloy. Hardness measurements, polarization and electrochemical impedance spectroscopy (EIS) were employed to study the mechanical and corrosion behaviors of the coatings. Field-Emission Scanning Electron Microscopy (FE-SEM) equipped with Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) were utilized to characterize the surface morphology and phase composition of the coatings. Also, coatings abrasive wear properties were evaluated with a modified ASTM G105 standard. FE-SEM image, EDS and XRD analysis revealed the presence of Si 3 N 4 in the coating. Furthermore, the results showed hardness of the coatings to increase from 380±50 HV for the anodized layer to 712±36 HV for the composite coatings that were formed in an electrolyte containing 6 gr/lit Si 3 N 4 nanoparticles. Electrochemical measurements indicated that corrosion resistance of the nanocomposite coating significantly increased compared to the anodized coating. In addition, the effect of Si 3 N 4 nanoparticles into the nanocomposite coatings on abrasive wear mechanism and mass loss rate of the coatings was investigated.