Evaluation of wear and corrosion behavior of nanostructure Ni-P-Al2O3 composite coatings

In this research, alumina particles within Ni-P electroless coating were co-deposited on mild carbon steel substrate. The structure of the coatings was investigated by X-Ray Diffraction (XRD) analysis and the particles content in Ni-P-Al2O3 coating was determined by image analysis software and using the micrographs obtained by Scanning Electron Microscopy (SEM). The tribological behavior of the coatings was evaluated by pin-on-disc method and by using 52100 steel pins. Potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) methods were also used to study the corrosion behavior of the coatings in 3.5wt.%NaCl solution. The results showed that the hardness and wear resistance have increased with raising the alumina particles in nanostructure Ni-P-Al2O3 composite coating, whereas the corrosion resistance has decreased due to the activation of pitting corrosion.