Volume 36, Issue 2 - Special issue: Advanced materials for corrosion resistant coatings / Issue editor: Lloyd H. Hihara

A set of unique properties can be derived by a proper combination of organic and inorganic segments in a coating composition. The synthesis of such hybrid coatings is a challenging task due to that a number of variable parameters need to be optimized to achieve the desired results. Similar to the copolymerization of macromolecular segments in a common solvent, sol–gel chemistry could provide a viable alternate for the development of single-phase coating composition. The coating derived through sol–gel and wet chemistry displays homogenous physical and chemical characteristics. A large variety of chemical moieties containing labile functional groups are available for the development of new coating compositions. This article briefly reviews such studies that are reported in majority of the academic sector.

Extreme water-repellent (superhydrophobic) coatings with water contact angle higher than 150° have caught the attention of corrosion researchers in the last decade as they can be used to protect metals and alloys against corrosion. The latter is a serious problem, as it can threaten human lives in addition to its deleterious effects on the economy and environment. Superhydrophobic coatings (SHCs) can be achieved by lowering the surface energy of a certain coating through combining some of its surface features at the microscale and nanoscales. Although SHCs can be prepared using many different easy techniques, none, to the best of our knowledge, has been applied, so far, on an industrial scale for protection against corrosion of metals and alloys. The present work explains the different models of superhydrophobic surfaces (SHSs) and reviews their fabrication and processing methods with a focus on the recent advances in the corrosion protection of the SHC.

In this review, most of the works are attempted to cover about corrosion protection of metals with molecular-tight atomic thin carbon layers of all sorts of graphene derivatives from the very beginning to the latest theoretical and experimental research findings, so as engineering achievements in the field up to date. Although high and tuneable electrical conductivity of graphene is the main feature exploited in majority of the applications such as catalysis, photocatalysis, electrocatalysis, low electrical but high chemical resistivity electrodes in batteries, and ultracapacitors, corrosion protection of metals favours the opposite – good physical separation and electrical insulation. Both of the latter ones lead to durable excellent protection, which can only be ensured by special design and implementation. Thus, the milestones of major hardships both on theoretical and practical sides are delineated similarly as utmost developments in circumventing all problems with an aim to ensure timely transfer from the research phase to successful industry utilisations. Relying on numerous works, this paper gives a comprehensive overview in the subjects of preparation, modification, and use of multiple sorts of graphene in the forms of neat, combined layers, and composite coatings on numerous metals. All performance parameters are given in detail. Chronological order of the article serves the purpose to give the reader a clear picture and an important clue on viability of strategies in the aspects of environmental friendliness, attainable maximum durability, and performance of corrosion protection with graphene films, as well as further advancements in the field expected to occur in the near future.