Effect of TiO2 nanoparticles on anticorrosion property in amorphous Ni-P-Cr composite coating in artificial seawater and microbial environment

To obtain the composite with a function of corrosion resistance in seawater and microbial environment, we apply low toxic electrolyte which contained Cr³⁺ instead of Cr⁶⁺ as a chromium source to produce Ni-P-Cr/TiO₂, Ni-P-Cr/ZrO₂ nanocomposite coatings, and Ni-P-Cr/TiO₂ microcomposite coating using direct current (DC) electrodeposits technique. The surface morphology, texture, and composition of the composite coatings are characterized by SEM, XRD, and EDX measurements, respectively. The corrosion behavior of the composite coatings is evaluated by polarization curves and electrochemical impedance spectroscopy (EIS). The results with more positive-shifting E_corr, lowest i_corr, and relatively high value of polarization resistance (R_p) proved that compared with other composite coatings, Ni-P-Cr/TiO₂ nanocomposite coating with its better passive film and unique antibacterial activity caused by TiO₂ nanoparticles incorporated, displayed excellent antibacterial and corrosion resistance property, consistent to the phenomenon that corrosion of this nanocomposite coating in SRB culture medium is not observed.