To improve the protective and technological properties of magnetite coatings (MC) formed on mild steel in solutions of ammonium nitrate, they were modified with a nitrogen-containing additive MD-3. The influence of the concentration of reagents and the temperature of the process on the thickness and stability of the magnetic field is analyzed. It is shown that both at high (100 ° C) and low (≤ 70 ° C) temperatures, the MC is loose. In the presence of the MD-3 additive, the optimal values of the concentration of ammonium nitrate and the temperature range are determined, which makes it possible to obtain the most stable MC. The analysis of the main lines of magnetite, obtained by the method of X-ray diffraction on steel with a conventional or modified MC, is carried out. It is shown that in the presence of MD-3 in the solution, in addition to the formation of magnetite, the formation of an amorphous phase of iron hydroxide occurs, and the size of magnetite crystallites decreases by a factor of 1.5 - 2.0 compared to the unmodified coating. It is shown that in presence of MD-3 the MC becomes more homogeneous and thinner than that formed in a pure solution. Various corrosion tests showed a linear increase of the protective properties of modified MCs with respect to the time of oxidizing.

Magnesium alloys are widely applied as structural materials in aerospace and automotive industries due to their light weight, excellent formability, high specific strength, and damping characteristics. Lithium has been added to magnesium alloys to improve ductility and reduce weight. On the other hand, the addition of lithium decreases their strength and, often, corrosion resistance. The present work aims to study the effect of Na₂MoO₄ on the corrosion inhibition of magnesium-lithium-aluminum alloys Mg–xLi–3Al (x = 4–15%) in 0.05 M NaCl solutions. The mechanism of corrosion inhibition using aqueous molybdate was characterized by the electrochemical measurements, hydrogen evolution, Raman spectroscopy, and SEM-EDX. Electrochemical measurements showed that the addition of 10 to 150 mM of molybdate inhibitor in 0.05 NaCl solutions results in the inhibition efficiency from 64 to 80 %, respectively. Raman results showed that the addition of Na₂MoO₄ inhibitor leads to the formation of a passive layer on the surface. In turn, the α+β MgLi phases present in the alloys are the centers of the surface passivation through the formation of a passive layer on the surface. The passive layer consists of Mg(OH)₂, crystalline molybdates, and mixed-valence molybdenum oxides. Concluding, molybdate is a highly-effective corrosion inhibitor of magnesium-lithium-aluminum alloys.

Corrosion is a severe issue in the effective utilization of metallic components and structures in industrial and coastal zones. Worldwide, substantial efforts have been dedicated to developing corrosion mitigation approaches. Among the different corrosion prevention methods, protective coatings are proven to be more effective in aggressive environments. Epoxy is a thermosetting polymer with unique chemical resistance, thermal stability, and mechanical integrity. The incorporation of different polymers in the epoxy matrix has motivated extensive research progress in the field of corrosion protective coatings. Epoxy matrix reinforced with polymer and nanofiller has resulted in improved adhesion, wear, barrier, and anti-corrosion properties of the nanocomposite coatings. Corrosion protection performance of a nanocomposite depends on nanofiller dispersion, physical and covalent interaction between matrix/nanofiller, and nanofiller adhesion to the substrate. Design and formulations of epoxy blend-based nanomaterials may enable appropriate tailoring of the overall performance of the resulting anti-corrosion coatings for advance technical applications, including aerospace, automotive, construction, and electronic devices. New formulation techniques can overcome challenges toward high-performance future epoxy-based coatings. This presentation is keen on updating the development, processing, and formulations of epoxy-based anti-corrosion coatings.

Abstract: Hot-dip galvanization is the most widely used method for the protection of steel against corrosion. The strategy of introducing hydrophobic nature to the hot-dip zinc coatings along with the corrosion resistance characteristics can enhance the protective efficacy and life time of the coatings. The effective enhancement in corrosion resistance and hydrophobic characteristics of hot-dip zinc coating can be achieved by incorporating metal oxide based composite into the coating matrix. In this contest, the present work explores the effect of introducing TiO₂–Al₂O₃ composite into hot-dip zinc coating for improving the hydrophobic and corrosion resistant characteristics of the coatings. The structural modification of the inner alloy layers of the hot-dip coating by using 0.2 wt.% of TiO₂-Al₂O₃ composite improves the hydrophobicity and corrosion resistance of the coating. Surface morphology, surface topography, chemical composition, hydrophobicity and electrochemical performance of the composite coatings studied by using various instrumental analyses confirm the enhancement in coating characteristics due to the incorporation of TiO₂-Al₂O₃ composite into the zinc matrix. The composite zinc coating incorporated with optimized TiO₂-Al₂O₃ exhibits enhanced hydrophobicity with a water contact angle of 101.32° than the pure zinc coatings. The high E_corr (-1267.17 mV) and low i_corr (475.57 μA/cm²) values of the composite coating as compared to the conventional zinc coating implies the improvement in corrosion resistance.

Lotus leaf based superhydrophobic surfaces exhibit water contact angle greater than 150° and sliding angle of less than 10°. Currently such superhydrophobic coatings are interests of common people due to its extra-ordinary self-cleaning performance. Since last two decades, tremendous developments have been done in design, fabrication and application of self-cleaning superhydrophobic coatings. Both sophisticated and easy ways in attaining self-cleaning superhydrophobic coatings are found in literature. In this review article, we are trying to summarize an easy and cheaper ways to fabricate self-cleaning superhydrophobic coatings. Various chemicals, methodologies and deposition methods adopted will be briefly discussed. This review article may found beneficial for the early career researchers working in the superhydrophobic research field.

Corrosion of metals leads to high maintenance costs as well as potential threats to structural health and safety. Here we demonstrate the coating of cobalt tungstate (CoWO₄) nanoparticles (NPS) / 5-mercapto-1-phenyl-1 H-tetrazole derivative (MPT) as a nanocomposite film on Cu surface for the blocking of micropores to hinder the propagation of metastable pits in an aggressive NaCl medium. The mechanism of interaction between the nanoparticles and tetrazole derivative, in addition to the mode of anchoring and blocking of penetration are all investigated. In this experiment, CoWO₄ was synthesized via a wet chemical route and thereafter, was combined with MPT at an optimized ratio thus formulating a nanocomposite corrosion inhibitor. Atomic force and Scanning electron microscopic images of the bare Cu reveal dip pits which by the coating of the nanocomposite were suppressed at the nucleation stage during exposure to the aggressive 3.5% NaCl electrolyte under flow condition. Electrochemical analysis shows high protection of Cu up to 97% efficiency in the presence of the newly formulated nanocomposite inhibitor film.

The corrosion of steel bars in concrete is a dangerous and extremely costly problem, that causes losses of serviceability and structural capacity in buildings and bridges. Once that the depassivation occurs, as a result of concrete carbonation or chlorides attack, at the steel-concrete interface the iron oxides expand approximately 2–6 times in volume, causing cracks and bond-slip degradation. In particular, the reinforcement - concrete bond degradation, influences the deformability of the element and consequently its service behaviour. The present study is a part of an extensive research project, CONSTIN, between Oslo Metropolitan University and Niccolò Cusano University aiming to evaluate the steel-to-concrete interaction in the presence of corrosion and to establish a variation law for the bond strength as a function of the corrosion level. The research aims to assess the influence of different level of corrosion on the interface between the concrete and the most typical steel reinforcement typologies (the steel strands, and the smooth and the ribbed bars), characterized by the same diameter (equivalent to 12 mm) and bonded length. The different level of corrosion is reached with a specific duration of exposition of the embedded reinforcements to the accelerated electrolytic corrosion process. Some details about the laboratory procedure, the duration of exposition and the current density will be provided. The preliminary results of the experimental campaign will be presented.

Stainless steel is a material manufactured for its high corrosive resistance and is the first choice of material in a range of applications. Microbial induced corrosion can cause significant damage to metals and is responsible for approximately 20% of corrosive damage. The corrosive resistance of stainless steel is reduced during manufacturing processes including welding or joining methods as the connection points prevent the metal from reforming its passivation layer. Additive manufacturing processes allow for intricate designs to be produced without the need for welding or bolts. However, it is unknown how the layering method of additive manufacturing (AM) will affect the passivation layer of stainless steel, and in turn its corrosive resistance. This research compares the corrosive resistance of 316L stainless steel produced using laser metal deposition and traditionally manufactured AISI 316 stainless steel to determine how the layering manufacturing method affects the corrosive resistance of the material. Samples are incubated over a 21 day period with Acidithiobacillus ferrooxidans (A.f) and Leptospirillum ferooxidans (L.f) in a modified HH medium with an approximate pH of 1.8 and kept at a constant temperature of 30°C. Scanning electron microscopy and Auger electron spectroscopy surface analysis techniques are used to identify any corrosive processes on the surface of the samples. This research is an introductory analysis into the corrosive resistance of AM 316 stainless steel using the laser metal deposition technique. Results show how stainless steel produced using laser metal deposition will react in acidic environments and are used determine if it could be a used in conjunction with other materials in underground pipes for acidic soils.

Prestressed reinforced concrete beams are widely used in industrial and commercial buildings, which are commonly exposed to aggressive environments and damaged by corrosion. This precast construction technique has been also used for the last 50 years in the majority of viaducts and bridges built in many countries like Italy. According to previous literature results, corrosion of prestressed concrete structures causes size reduction of strands, degradation of mechanical properties of steel, cracking of the surrounding concrete and bond decay at steel‐to‐concrete interface. The mixing of these effects strongly reduces the bearing-capacity of prestressed reinforced concrete members, changing the failure mechanism as well. In the framework of the OPTION research project between Niccolò Cusano University and Oslo Metropolitan University, an experimental campaign investigates the behaviour of corroded prestressed beams. Four prestressed beams (cross section size 200 × 300; total length 3000 mm; clear span 2700 mm) were first subjected to artificial corrosion, to obtain different damage levels, and then were tested in four-point bending. The goal is to estimate the corrosion level making a deteriorated prestressed reinforced concrete beam less ductile keeping the strength unchanged. In the present study, the first experimental results and some details about the laboratory procedure are presented.

Thermally sprayed aluminium (TSA) coatings are increasingly used to mitigate corrosion of offshore pipelines and structures. With the increase in the use, the knowledge related to their performance is growing. However, it would appear that the increased engineering applications is not supported by extensive research and in many cases due to improper application or lack of quality control, some issues are beginning to emerge. The data available in literature on the low and high temperature performance of these coatings is limited. To address the issues highlighted above, TWI carried out several research projects, including JIPs, collaborative projects and PhD projects, to quantify the effect of coatings damage in simulated service conditions at various temperatures. The research thus far indicate that TSA is capable of protecting steel at various temperatures in seawater even when a small through-thickness defect in the coating is present. The presentation will disseminate the results of various projects carried out at TWI and summarize the requirements that needs to be considered while selecting these coatings for offshore service.