Microbial corrosion is a universal phenomenon in salt water media such as seawater and wastewater environments. As a kind of efficient protective metal coating for steel, the damage of the Zn–Ni alloy coating was found to be accelerated under microbial corrosive conditions. To solve this problem, chitosan, which is considered a natural product with high antibacterial efficiency, was added to Zn–Ni electrolytes as a functional ingredient of electrodeposited Zn–Ni–chitosan coatings. It was found that the addition of chitosan significantly and negatively shifted the electrodeposition potentials and influenced the Ni contents, the phase composition, and the surface morphologies. By exposing the coatings in a sulfate-reducing bacteria medium, the microbial corrosion resistance was investigated. The results showed that compared to the Zn–Ni alloy coating, Zn–Ni–chitosan coatings showed obvious inhibiting effects on sulfate-reducing bacteria (SRB) and the corrosion rates of these coatings were mitigated to some degree. Further research on the coatings immersed in an Escherichia coli-suspended phosphate buffer saline medium showed that the bacteria attachment on the coating surface was effectively reduced, which indicated enhanced antibacterial properties. As a result, the Zn–Ni–chitosan coatings showed remarkably enhanced anticorrosive and antibacterial properties.

In this work, the photo-catalytic activity of TiO₂ is considerably enhanced via sensitization with CdIn₂S₄, and its application for protecting Q235 from corrosion in splash zones is examined. TiO₂ nanotube arrays (NTAs) are prepared on a flat Ti substrate via two-step anodization. CdIn2S4 is deposited on the surface of TiO₂ NTAs by hydrothermal reaction. TiO₂ NTAs with enormous specific surface areas and large-diameter hollow nanostructures are found to benefit the immobilization of CdIn₂S₄. As a narrow band gap semiconductor, CdIn₂S₄ is able to extend the light absorption range of TiO₂, and the construction of an n–n type hetero-junction accelerates the separation of carriers. Strong solar light, which accelerates the corrosion of Q235 in the splash zone area, is converted into the necessary condition for protecting Q235 from corrosion. In this work, TiO₂ is sensitized with MoS₂ microspheres (MoS₂/TiO₂ nanocomposites), which were prepared on a flat Ti substrate via a two-step anodization and hydrothermal method, sequentially.

The study is based on the study of the effect of an organic compound (OC) - hydrocinnamic (3-phenylpropanoic) acid on the bacterial cells of SRB (sulfate-reducing bacteria), which are stimulants of corrosion processes. Selection of conditions of use and a quantitative assessment of the effectiveness of the inhibitory (biocidal) action of the studied OC, which can be used to protect steel from corrosion in environments containing SRB. In the course of the study, the effect of OC on the development of SRB was studied and such parameters as the change in the pH value and the redox potential of the samples in the medium, the number of bacteria and the content of biogenic hydrogen sulfide depending on the concentration of the used OC were determined. The main conclusions are drawn about the inhibitory corrosion and biocidal actions of the test OC by assessing the corrosion rate of steel samples and the protective effect depending on the selected concentrations of the OC by gravimetry. An additional assessment of the inhibitory effect was carried out by the method of electrochemical impedance spectroscopy and by the method of taking the polarization curves of the test samples.

The article investigated the creation of a composite electrochemical coating (CEC) zinc-inhibitor with the inclusion of an organic compound (OC) with biocidal and inhibitory effects, which can be used to protect steel from corrosion in environments containing sulfate-reducing bacteria (SRB). The coating was applied to steel by electrochemical deposition. The OC was turned on by modifying the zinc sulfate electrolyte. The evaluation of the protective effect of CEC against microbiological corrosion was carried out during a laboratory study of samples with coatings placed in a Postgate "B" inoculated SRB medium for 7 days. In the course of the study, such parameters as changes in the electrode potential of samples in the medium, hydrogen index and redox potential of the medium, concentrations of bacterial cells and biogenic hydrogen sulfide were determined. At the end of the tests, the corrosion rate and the protective effect of the coating by the gravimetric method were determined. Evaluation of the inhibitory effect was carried out by electrochemical impedance spectroscopy and polarization curves of samples with CEC, exposed for 7 days in inoculated SRB nutrient medium Postgate "B". The study found: improvement of the coating structure due to the introduction of OC, the biocidal and inhibitory effects of CEC, a decrease in the corrosion rate of CEC by about 2 times with respect to the zinc coating.