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Epoxy zinc-rich coatings are widely used in harsh environments because of the long-lasting cathodic protection of steel surfaces. The purpose of this paper is to use flake zinc powder instead of the commonly used spherical zinc powder to reduce the zinc powder content.

In this paper, the authors have prepared an anticorrosive zinc-rich coating using a flake zinc powder instead of the conventional spherical zinc powder. The optimal dispersion of scaly zinc powder in zinc-rich coatings has been explored by looking at the surface and cross-sectional morphology and studying the cathodic protection time of the coating.

The final epoxy zinc-rich coating with 35 Wt.% flake zinc powder content was prepared using sand-milling dispersions. It has a similar cathodic protection time and salt spray resistance as the 60 Wt.% spherical zinc-rich coating, with a higher low-frequency impedance modulus value.

This study uses flake zinc powder instead of the traditional spherical zinc powder. This reduces the amount of zinc powder in the coating and improves the corrosion resistance of the coating.

The purpose of this study is to evaluate the effect of graphene, basalt flakes and their synergy on the corrosion resistance of zinc-rich coatings. As the important heavy-duty anticorrosion coatings, zinc-rich coatings provided cathodic protection for the substrate. However, to ensure cathodic protection, a large number of zinc powder made the penetration resistance known as the weakness of zinc-rich coatings. Therefore, graphene and basalt flakes were introduced into zinc-rich coatings to coordinate its cathodic protection and shielding performance.

Three kinds of coatings were prepared; they were graphene modified zinc-rich coatings, basalt flakes modified zinc-rich coatings and graphene-basalt flakes modified zinc-rich coatings. The anticorrosion behavior of painted steel was studied by using the electrochemical impedance spectroscopy (EIS) technique in chloride solutions. The equivalent circuit methods were used for EIS analysis to obtain the electrode process structure of the coated steel system. Simultaneously, the corrosion resistance of the three coatings was evaluated by water resistance test, salt water resistance test and salt spray test.

The study found that the addition of a small amount of graphene and basalt flakes significantly improved the anticorrosion performance of coatings by enhancing their shielding ability against corrosive media and increasing the resistance of the electrochemical reaction. The modified coatings exhibited higher water resistance, salt water resistance and salt spray resistance. The graphene-basalt flakes modified zinc-rich coatings demonstrated the best anticorrosion effect. The presence of basalt scales and graphene oxide in the coatings significantly reduced the water content and slowed down the water penetration rate in the coatings, thus prolonging the coating life and improving anticorrosion effects. The modification of zinc-rich coatings with graphene and basalt flakes improved the utilization rate of zinc powder and the shielding property of coatings against corrosive media, thus strengthening the protective effect on steel structures and prolonging the service life of anticorrosion coatings.

The significance of developing graphene-basalt flakes modified zinc-rich coatings lies in their potential to offer superior performance in corrosive environments, leading to prolonged service life of metallic structures, reduced maintenance costs and a safer working environment. Furthermore, such coatings can be used in various industrial applications, including bridges, pipelines and offshore structures, among others.

In this special feature details are given of those British paints which can be described as corrosion‐resistant primers, both one‐ and two‐pack. The materials are generally classified according to the base or pigment which actively prevents corrosion—e.g. metallic zinc in zinc/epoxy formulations— or by the base which produces a barrier action against corrosion, e.g. bitumen in bituminous paints. Exceptions to this are the etching primers, which are separately classified. About 300 primers are described, the manufacturers' names and addresses being cross‐indexed and listed separately on page 48.

High strength low alloy steels have attained wide acceptance as structural materials. Research and development have led to different corrosion preventive methods. High strength low alloy (HSLA) of composition C(0.4%), Mn(0.7%), Si(0.25%). Cr(0.8%), Ni(1.7%) was selected for this study. Epoxy iron oxide, epoxy micaceous iron oxide (MIO), zinc‐rich epoxy and zinc ethyl silicate were used for painting the HSLA panels (150mm × 100mm × 3mm). Physical properties such as film thickness, specific gravity, viscosity, drying times of paints were evaluated and salt spray test, AC impedance and metallographic examination were carried out. Performance of zinc ethyl silicate coating over HSLA was found to be the best followed by epoxy micaceous iron oxide system.

The purpose of this paper is to explore the application of triglycidyl resin (TGC) prepared from cardanol as partial replacement of conventional bis-phenol A (BPA) based epoxy resin for zinc rich primers (ZRPs).

The synthesis of new platform chemicals that are based on renewable resources has been accepted as a strategy to contribute to sustainable development due to the anticipated depletion of fossil oil reserves and rising oil prices. We prepared a tri-functional epoxy resin from cardanol which can be used as partial replacement of BPA based epoxy. The ZRPs were prepared using 50:50 ratio of TGC:BPA epoxy, and the coatings were evaluated for mechanical, chemical and anticorrosive properties.

The 50 per cent replacement of BPA based epoxy by TGC resulted in at par mechanical, chemical and anticorrosive properties as evaluated by various methods. The successful implementation can thus contribute to sustainable development by “green chemistry” route.

The prepared TGC resin in the current work was studied for application in ZRPs. This can also be explored for high performance coatings, adhesives and other engineering applications.

The TGC binder was prepared by simple two-step reaction. This can successfully be used as binder for coating application without any modifications.

A novel approach of using green and ecofriendly TGC resin as replacement of high cost BPA based epoxy was explored and can be implemented for numerous applications.

This paper aims to study the corrosion performance and physical properties of hybrid paint systems based on zinc-rich primer (ZRP) and to determine the optimum modification approach that guarantees the most overall performance enhancement for the developed coating films that have been fabricated based on the usage of ZRP.

Four different approaches were applied to enhance the corrosion protection performance and the physical properties of ZRP-based paint systems, namely, incorporation with TiO₂ pigment, introducing SiO₂ nanoparticles, usage of polyamide curing agent and application of epoxy base coating as a second layer. The physico-mechanical properties were examined using pull-off test, glossiness test, pencil hardness test and cross-cut adhesion tape test. Moreover, the contact angle measurement was used to study the wettability of the developed coated surfaces and the corrosion protection performances were evaluated by using electrochemical impedance spectroscopy and salt spray test.

The obtained results revealed the ability of a certain approach to enhance the physical and corrosion protection properties of the ZRP paint system. Moreover, developing an intact hydrophobic nanocomposite paint system based on the usage of ZRP as the host matrix and SiO₂ nanoparticles as the reinforcing agent was confirmed without altering the cathodic protection mechanism or the other desired characteristics of ZRP paint system.

The innovation of this work can be clearly observed by the ability to enhance the physical and corrosion protection properties of ZRP with four different approaches.

IN many of the industrial and other aggressive environmental conditions encountered today a synthetic, plastics‐type of paint system must be used, since traditional paints give poor and limited service. However, for these synthetic paints to be fully effective, they must be applied to more scrupulously prepared surfaces. The finer tolerances and more exacting application requirements of synthetic plastics‐type coatings, such as the epoxies, must be appreciated. Once these are understood it is not difficult to put the materials into use, where they give outstanding long‐term protection. Some of the physical, chemical and solvent‐resistance characteristics of the epoxy resin coatings can, of course, be attained with other synthetic paints, and all these materials have their place in the paint manufacturer's armoury. There are resins showing better flexibility and chemical or heat resistance than the epoxies, but the latter are outstanding in combining these and other characteristics to a marked degree—hence their fairly rapid user acceptance. There is inevitably over‐lapping in characteristics with other coatings, particularly the polyurethanes, and it is not claimed here that epoxy coatings can confer protection against all corrosive environments.

Microbes that are able to grow on different surfaces can cause the deterioration of the underlying layers because of their metabolic activity. The purpose of this study is report the ability of fungi-bacteria consortium (FBC) in anaerobic media, and marine strain bacteria, to attach onto UNS 1008 carbon steel and zinc epoxy coats.

Impedance analysis, scanning electronic microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to evaluate the adherence, biofilm formation and corrosion effect of FBC and marine bacteria onto UNS1008 carbon steel in anaerobic and aired conditions, respectively. In a similar way, the anticorrosive performance of hybrid coats on UNS 1008 carbon steel against marine bacteria.

In aerobic conditions, the outer layer shows a micro-crack appearance and several semi-sphere products that could be because of spore formation. In anaerobic conditions, evidence of iron sulfide surrounded by a mixture of sulfur-containing extracellular polymer substance was observed by SEM images and EDS analysis. The presence of hybrid coats (zinc epoxy with carbon nanotubes CNT content) affected the level of microbial adherence and the concentration of corrosion products (Fe₂O₃, Fe(OH)₂ and FeS); the cell attachment was lower when the steel surface was coated with Zn/CNTs.

This study opens a window for further evaluations of CNTs associated with metals as active materials to assess the corrosion on extreme corrosive environments, like in oil and gas industries the microorganisms play an important role either to increase or reduce the corrosion processes.

Coating concrete pipes Metallic Coatings Ltd, of Manchester Airport South Site Works, Wilmslow, Cheshire, report that they are currently developing in two areas:

The purpose of this study was to investigate the polyacrylic polymer/Al₂O₃ as a new nanocomposite coating to protect brass and Al-bronze in 3.5% NaCl and the role of alumina formulation on their protection efficiency

The corrosion efficiency of the nanocomposite coating (NCC) was evaluated by open circuit potential and electrochemical impedance spectroscopy (EIS).

The protection efficiency was more in the case of Al-bronze even for the same formulation of alumina NCC indicated the Cu substrate contribution. The Cu oxides in alloys and Al₂O₃ from the NCC and Al-bronze were responsible for this protection.

All the techniques supported each other, the presence of alumina was responsible for the corrosion protection efficiency.