Corrosion protection of cold-rolled steel with alkyd paint coatings composited with submicron-structure types polypyrrole-modified nano-size alumina and carbon nanotubes

Corrosion protection with zinc-rich epoxy paint coatings embedded with various amounts of highly dispersed polypyrrole-deposited alumina monohydrate particles

“…On the other hand, around ~5−8% of the zinc surface area is estimated to interact with PCAIPs within 10 nm distance volume range in the vicinity of the grains. In fact, despite the low concentration of the PCAIPs such particles are able to afford valuable anodic protection to metallic surfaces [54]. On the other hand, the low PPy contents (and the nano-size alumina) provide low density paths across epoxy of the hybrids entailing in hindered permeation of the electrolyte.…”

Measurable and Influential Parameters That Influence Corrosion Performance Differences between Multiwall Carbon Nanotube Coating Material Combinations and Model Parent Material Combinations Derived from Epoxy-Amine Matrix Materials

“…Our results here indicated that the corrosion rate correlated well with the distribution of water hydrogen bonding states. However, we cannot discount that other mechanisms contribute to the overall corrosion performance of applied coating material combinations containing MWCNTs as many critical polymer performance characteristics are improved simultaneously by incorporating MWCNTs (e.g., modulus, adhesion, glass transition temperature). ,,,,,, These coating performance characteristics in a salt fog/full immersion environment may be influenced by the relative concentration of water hydrogen bonding interactions as it is has been noted that the overall water saturation concentration may not be a reliable predictor of the instantaneous polymer properties. , Thus, the mechanistic interplay between the water hydrogen bonding interactions (each at the coating/substrate interface, the polymer/air interface, and within the polymer) and critical properties that affect the cathodic delamination rate (e.g., coating adhesion, ion transport/solvation, and facilitation/management of radical based interface degradation reactions) have the potential to increase a coatings corrosion resistance if tuned to address the both adhesion and water transport capabilities via hydrogen bonding. The mechanistic interdependence between adhesion and water hydrogen bonding states at the coating substrate/interface for the specific function of cathodic delamination control requires further understanding and delineation between the dominate influence of each complex singular event and interaction parameters between events/processes and distinct mechanisms.…”

“…In addition to electroactive materials for corrosion control, e.g., conductive polymers and sparingly water-soluble inorganic pigments, other materials such as carbon nanotubes (CNTs) dispersed into polymer matrix materials have resulted in diminished corrosion rates. − CNTs are quasi-one-dimensional high aspect ratio graphene nanostructures with unique electrical and physical properties. − Often, the improved corrosion performance of CNTs dispersed into polymers were attributed to, singularly or in combination, increased barrier properties (tortuosity), increased adhesion and improved mechanical properties, and/or the formation of electrically conducting networks commonly described and measured as able to facilitate electrochemical reactions at low concentrations. ,,,,, Calculations have also indicated that environmental contaminants and corrosion byproducts (e.g., chlorine, oxygen, hydroxyl ions, and sulfates) adsorb to the CNT sidewall and end-caps which contributes to reducing migration through coatings and the concentration of these species at the coating/metal interface . Thought to be critically important to our work, however, some studies have also shown that the water diffusivity and water absorption at saturation for a given MWCNT concentration remain, within detection limits, constant and yet similar systems also exhibit reduced corrosion rates; , hence, additional parameters and/or mechanisms must also exist which directly contribute to the overall corrosion performance, i.e., additional mechanistic considerations are missing from our understanding of the overall corrosion process of coated substrates.…”

Hybrid Zinc-Rich Paint Coatings

“…Statistically even distribution of spheroids of both the zinc pigments and the nano-size particles are considered at average sizes of 3 μm and 30 nm, respectively. 101 Furthermore, semiconducting particles should affect the sacrificial anodic current output of zinc. The latter is the typical maximum interparticle distance where electrical percolation takes place in polymeric composites by an electron tunneling mechanism.…”