During exploitation, the properties of the epoxy coating deteriorate and therefore, it is necessary to modify it with metal particles. In this paper, spherical aluminium nanoparticles (Al NP) of 100 nm with 99.9% purity were used to modify the epoxy coating for the better corrosion protection of grey cast iron. Pure Al has a high corrosion resistance and can form a thin protective film that prevents its further oxidation, thus, becoming inert and environmentally friendly. To examine these facts, different concentrations (0.5, 0.75, 1.0, 3.0, and 6.0 wt.%) of Al nanoparticles were dispersed in the epoxy coating. The surface of the modified nanocomposite coating was analysed using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Furthermore, the physical properties such as colour, thickness, hardness, and adhesion to the cast iron surface were tested as well. The same properties were tested by exposing the sample plates to corrosive conditions in the climate chamber. Their anticorrosion properties were investigated using electrochemical impedance spectroscopy (EIS) by their immersion in 3.5 wt.% NaCl solution as a corrosive medium. The coating with 0.75% Al NP showed the best corrosion resistance after 10 days of exposure in salt water, while the sample with 1.0% Al NP showed the best corrosion resistance after exposure to the icing/deicing process.

This paper presents the conformity assessment process of the epoxy coating thickness applied on water pipes made of gray cast iron with the specifications given for this kind of coating appliance. An epoxy coating was applied to prevent a special form of corrosion called the graphitization of cast iron. In order for the pipe to withstand its designed service life, it is necessary to ensure the required thickness of the applied coating. In accordance with the EN 877 norm, the thickness of the epoxy coating on the pipes for the projected corrosiveness of the environment C4 and the durability of 20 years is at least 70 μm and this indicates the required accuracy of the product. To achieve the desired product quality, statistical control of the coating application process was carried out and the impact of uncertainty associated with the measurement result was analyzed. Considering the quality of the coating application process and the quality of the measuring system, and to ensure the quality of products and to reduce consumer risk, the optimal thickness of the coating was determined.

The purpose of this research is to investigate the influence of the phosphatizing process with Ni2+, Ce3+, and Ti2+ ions on the properties of the coating to obtain better corrosion protection of the metal. Steel corrosion occurs through physicochemical interaction between the metal and its surrounding environment. This leads to a change in the metal’s physical, mechanical, and optical properties that can cause damage to the functionality of the metal, which in turn may result in accidents or other malfunctions. Carbon steel grade has limited resistance to corrosion, depending on the carbon content and alloying element, the microstructure, and the surrounding environment of the material. This paper present tests that have been carried out on some of the physicochemical properties of protective epoxy and polyurethane coating on carbon steel grade. Coatings represent one of the methods available to protect metal surfaces from corrosion. Coating properties such as thickness, hardness, and adhesion were investigated. The same properties were tested by exposing the sample plates to corrosive conditions of the humid chamber and seawater. Their anticorrosion properties were explored by electrochemical impedance spectroscopy (EIS) techniques under immersion in 3.5 wt.% NaCl solutions as a corrosive medium. Part of the samples prior to application of the coatingwere modified with a phosphate solution containing metal ions: Ni2+, Ce3+, and Ti2+ to further investigate the effects of phosphatization on the properties of the coating. After exposure of the plates to the salt and moist chamber conditions, no traces of corrosion products, cracking or peeling of the coating were found on the surfaces. The adhesion properties were tested by the pull-off adhesion test. It was found that metal/polymer adhesion was satisfied according to EN ISO 4624:2016 and had the same value for all samples. However, a detailed EIS analysis showed a higher resistance of phosphate samples with Ce3+ ions than samples that were phosphated with Ni2+ and Ti2+ ions and those that did not have a sparingly soluble phosphate salt layer.

Organic coatings are used as one of the key surface protection methods to protect cast iron pipelines against corrosion due to their cost efficiency and a variety of applications. In most metallic systems that are protected by organic coatings, the performance depends on the response of the coating to corrosion stresses to which they are exposed during operation. One of the most dangerous factors causing chemical damage to coatings are the acidic and chloride aggressive media. Such damage reduces the protection effectiveness thus leading to blistering, cracking, increase in pore volume and number, as well as loss of adhesion. Moreover, the influence of aggressive media impairs also aesthetic characteristics. In the experimental part of the paper, analyses of the physical and chemical properties of epoxy coatings applied on the metal substrate in phosphoric acid, acetic acid and 3.5 wt% NaCl solutions were carried out. The test results showed that the physical properties of epoxy coatings were satisfactory in the acidic medium, but electrochemical tests in 3.5 wt% NaCl solution showed reduced corrosion protection.

Nanoparticles are capable of making more durable and stronger materials with better chemical resistance. They are used for a wide range of applications. Likewise, the potential of metal nanoparticles as antimicrobial agents has been widely studied. In this work, we investigate various nanoparticles (Al, Ni, Ag) incorporated into epoxy coating. The anticorrosion and antibacterial properties of the unmodified and modified coatings were evaluated. According to the SEM and EDS analyses, the coating did not contain agglomerates, which confirms the quality of the dispersion of inorganic nanoparticles in the coating. After 24 h and 10days immersions in a 3.5 wt.% NaCl solution, the corrosion behaviour for all nanocomposite was studied by means of EIS investigations. The study included the evaluation of the inhibition zone of the nanoparticles and the antimicrobial properties of the nanocomposite. It was found that the nanoparticles of Al and Ag provide excellent antibacterial properties. The epoxy nanocomposite with Al NP showed the migration of ions in the range from 0.75 to 1 mg/L in a wastewater solution for 30 days, indicating a potential for antimicrobe activity. The 1% Al NP epoxy nanocomposite showed good anticorrosion and antibacterial properties and demonstrated great potential for applications in pipelines.