Pretreatment with a β-Cyclodextrin-Corrosion Inhibitor Complex Stops an Initiated Corrosion Process on Zinc

Abstract

Metal pretreatment is typically the first step in a reliable corrosion protection system. This work explores the incorporation of complexes between the cyclic oligosaccharide β-cyclodextrin (β-CD) and the molecular organic corrosion inhibitor 2-mercaptobenzothiazole (MBT) into an oxide-based pretreatment layer on metallic zinc. The layers were produced by a precorrosion step in the presence of β-CD. Resulting films have a morphology dominated by spherical particles. X-ray photoelectron spectroscopy (XPS) investigations of the surfaces show the sulfur atoms of MBT to be partially oxidized but mostly intact. Samples pretreated with such a layer where subsequently coated with a model polymer coating, and the delamination of this model coating from an artificial defect was monitored by a scanning Kelvin probe (SKP). SKP results show a slow down of delamination after several hours of the ongoing corrosion process for surfaces pretreated with the complexes. Finally, a lifting of the electrode potential in the defect was observed, with a subsequent complete stop in delamination and repassivation of the defect after ≈10 h. The repassivation is attributed to the release of MBT after initiation of the corrosion process. Most likely, the increase of pH, combined with the availability of aqueous solution, facilitates the MBT release after initiation of a corrosion process. Consequently, complexes formed from β-CD and corrosion inhibitors can be effectively incorporated into inorganic pretreatments, and the inhibitor component can be released upon start of the corrosion process.

Molybdate and Phosphate Cross-Linked Chitosan Films for Corrosion Protection of Hot-Dip Galvanized Steel

“…A chitosan-silane hybrid film for corrosion protection of zinc with favorable electrochemical properties and low cathodic delamination rates was reported, as it may dampen extreme pH values during delamination . The incorporation of organic corrosion inhibitors into chitosan decreased corrosion rates of zinc. , Similar effects were found for cyclic oligosaccarides; , in this case, corrosion inhibition has been attributed to a decreased amount of point defects in the native oxide layer . Chitosan and other chitin-based compounds are also known for their high affinity to heavy metals, e.g., zinc, chromium, gold, and molybdenum, which has led to a wide range applications for environmental remediation. , Chitosan with phosphate has been used, e.g., to tailor corrosion of magnesium alloys, − titanium alloys, − or stainless steels, − for implants.…”

Performance Evaluation of New Chalcone Oxime Functionalized Graphene Oxide as a Corrosion Inhibitor for Carbon Steel in a Hydrochloric Acid Solution

“…Corrosion causes substantial economic damage and catastrophic harm, as it destroys crops and infrastructure, causing financial, health, and safety issues. The direct cost of metal degradation is projected to be $2.5 trillion a year globally. − Metal corrosion has also resulted in major disasters. For example, in November 2013, the Donghuang II pipeline suddenly detonated in Qingdao, eastern China, due to Sinopec’s corroded underground pipeline, killing 62 people and injuring 136 others.…”

Targeted synthesis of two iron(III) tetradentate dibasic chelating Schiff base complexes toward inhibition of acidic induced steel corrosion: Empirical and DFT insights

“…[6][7][8] Thus far, great consideration has been given to preventing C-steel corrosion in various pickling aggressive media involved in a wide range of applications. [9][10][11] Subsequently, the addition of inhibitors to the corrosive medium is considered one of most effective and the simplest methods to inhibit metals from corrosion. In past decades, large numerals of compounds have been examined for corrosion protection.…”

“…[ 6–8 ] Thus far, great consideration has been given to preventing C‐steel corrosion in various pickling aggressive media involved in a wide range of applications. [ 9–11 ]…”