Electrochemical exfoliation of graphene nanosheets and development of a novel efficient Ni-CeO2-Gr ternary nanocomposite coatings for dual functional anti-corrosion and wear-resistance

Nickel-based coatings offer excellent corrosion, wear resistance, and mechanical strength, and can be further improved with additives, making them ideal for harsh environments like marine and chemical industries. In the present study, graphene (Gr) nanosheets were synthesized via electrochemical exfoliation and a novel Ni-CeO₂-Gr nanocomposite coating was prepared by an electrochemical co-electrodeposition technique on a Cu substrate in a traditional Watts bath. The coatings (pure Ni, Ni-Gr, Ni-CeO₂ and the ternary Ni-CeO₂-Gr) were characterized using optical microscopy, scanning electron microscopy (SEM) coupled with energy-dispersive spectrometry (EDS), X-ray diffraction (XRD), Raman spectroscopy, Vickers microhardness and micro-scratch tests. The electrochemical properties of the coatings were evaluated by electrochemical impedance (EIS) and DC-polarization measurements in 0.5 M NaCl. SEM-EDS, Raman, and XRD analysis confirmed the successful synthesis of high-quality graphene and the incorporation of CeO₂ nanoparticles and graphene nanosheets into the nickel coating matrix. It was found that the ternary Ni-CeO₂-Gr coating exhibited a high microhardness (915.6 HV), improved cohesive strength and enhanced corrosion resistance (544 KΩ.cm⁻²) compared to pure Ni coatings (30 KΩ.cm⁻²) due to the synergistic effect of the graphene and CeO₂ duplex layer within the Ni matrix, forming a robust anticorrosion barrier. These findings offer valuable insights into the designing highly efficient materials for corrosion protection.