Recent Trends in the Characterization and Application Progress of Nano-Modified Coatings in Corrosion Mitigation of Metals and Alloys

Abstract

Nanotechnology is a discipline of science and engineering that emphasizes developing, modifying, characterizing, and using nanoscale components in a variety of applications. Owing to their multiple advantages, including adhesion strength, surface hardness, long-term and extra-high-temperature corrosion resistance, improvement of interfacial behavior, etc., nanocoatings are efficiently utilized to minimize the influence of a corrosive environment. Additionally, nanocoatings are often applied in thinner and finer concentrations, allowing for greater versatility in instrumentation and reduced operating and maintenance costs. The exemplary physical coverage of the coated substrate is facilitated by the fine dimensions of nanomaterials and the significant density of their grounded boundaries. For instance, fabricated self-healing eco-sustainable corrosion inhibitors including PAC/CuONPs, PAC/Fe3O4NPs, and PAC/NiONPs, with uniform distributions and particulate sizes of 23, 10, and 43 nm, correspondingly, were effective in producing PAC/MONPs nanocomposites which exhibited IE% of 93.2, 88.1, 96.1, and 98.6% for carbon steel corrosion in 1M HCl at the optimum concentration of 250 ppm. Therefore, in this review, further steps are taken into the exploration of the significant corrosion-mitigation potential and applications of nanomaterial-based corrosion inhibitors and nano-modified coatings, including self-healing nanocoatings, natural source-based nanocoatings, metal/metallic ion-based nanocoatings, and carbon allotrope-based nanocoatings, to generate defensive film and protection against corrosion for several metals and alloys. These have been illuminated through the in-depth discussion on characterization techniques such as scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), etc. After providing a general summary of the various types of nanomaterials and their protective mechanisms in wide corrosive media, we subsequently present a viewpoint on challenges and future directions.