Nip/Zno-Doped C3n4 Nanocapsules: A New Highly Corrosion-Resistant Electroless-Plated Coating with Superior Mechanical and Antibacterial Properties

Abstract

Carbon nitride (C3N4) nanomaterials has superior mechanical, thermal and tribological properties, which make them attractive for various applications including corrosion resistant coatings. In this research, newly synthesized C3N4/ZnO nanocapsules with different concentrations (0.50, 1.00 and 2.00 g) of doped ZnO were incorporated in the NiP metallic coating using electroless deposition technique. The nanocomposite coating was heat treated at 400 oC for 1h. The as-plated and heat treated nanocomposite coatings were characterized for their structure, elemental composition, thickness, morphology, roughness, wettability, hardness and corrosion protection properties to evaluate the influence of undoped and doped C3N4 with ZnO on the NiP coating. The results indicated that the microhardness of as-plated and heat treated nanocomposite coatings was significantly improved after the incorporation of undoped C3N4 nanocapsules. About 21% further improvement is done with 0.5g ZnO doped C3N4 nanocapsules, where the NiP-C3N4/0.5g ZnO composite coating showed the maximum microhardness of 680 and 1,330 HV200, before and after heat treatment, respectively. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) outcomes revealed that the corrosion resistance of heat treated undoped and doped NiP- C3N4 coatings are higher than the corresponding as-plated ones. The highest corrosion resistance is achieved on the as-plated and heat treated NiP C3N4 coatings that is doped with 1.00 g ZnO. Although the presence of ZnO in the C3N4 capsules increased its surface area and porosity, the C3N4/ZnO nanocapsules prevent the localized corrosion and enhance the corrosion resistance of the nanocomposite coatings by filling the micro defects and pores of the NiP matrix. Furthermore, the colony counting method used to evaluate the antibacterial behavior of the as-plated and heat-treated coatings demonstrated superior antibacterial properties, namely after heat treatment. Therefore, the novel prospective C3N4/ZnO nanocapsules can be utilized as a reinforcement nanomaterial in improving the mechanical and anticorrosion performance of NiP metallic coatings in chloride media, together with providing superior antibacterial properties.