Enhanced protective properties of hydrothermally synthesized Ni(OH)2-YSZ/reduced graphene oxide (rGO) nanocomposite coating

The hydrothermally synthesized Ni(OH)2-YSZ composite reinforced with reduced graphene oxide (rGO), was applied for corrosion protection of 316L stainless steel (SS) by electrophoretic deposition. The effect of rGO introduction on corrosion properties of Ni(OH)2-YSZ coating was investigated. The morphology and structures were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The corrosion properties of specimens were determined by Tafel polarization and electrochemical impedance spectroscopy (EIS) analysis in 3.5 wt% NaCl corrosive solution. The results showed that the corrosion protection properties were remarkably improved by the introduction of rGO into Ni(OH)2-YSZ composite film. The Ni(OH)2-YSZ/rGO coated SS showed a higher charge transfer resistance (1.85 × 105 Ω cm2) compared to Ni(OH)2-YSZ coated SS (6.12 × 104 Ω cm2) and bare 316L SS (4.55 × 104 Ω cm2). The addition of rGO to Ni(OH)2-YSZ composites efficaciously improved the dispersion of nanoparticles and also reduced their size. Consequently, the electrochemical enhancement caused by rGO introduction was attributed to the nano-sized particles, compaction, and uniformity of the coating, which efficiently prevented the steel substrate from corrosion attack.