Sergey M. Gaidar

In order to improve biostability while maintaining the protective efficiency of St3 steel in a 3.5% NaCl solution, the efficiency of zinc undecylenate as a biocidal additive to a preservative oil (PO) containing a non-ionic surfactant was studied. The resistance of the oils to mold fungi was evaluated according to GOST 9.052-88 (method 3) using a mixed suspension of spores of five fungal species: Aspergillus niger, Scopulariopsis brevicaulis, Penicillium chrysogenum, Penicillium cyclopium, and Paecilomyces varioti, under conditions simulating mineral contamination. The corrosion behavior was evaluated by gravimetric mass-loss measurements (GOST 9.054-75) and potentiodynamic polarization in a 3.5% NaCl solution. The initial preservative oil without the biocidal additive was shown to promote the growth of mold fungi, whereas the addition of zinc undecylenate at the concentrations of 1.0–3.0% to the preservative oil suppressed visible mycelial growth without reducing the protective properties. All the formulations under study retained a high level of protective efficiency (Z ≥ 98.4%), while the maximum protective effect reached 99.6–99.7% according to the gravimetric tests and up to 99.4% according to the electrochemical measurements at 3.0% content of zinc undecylenate. Analysis of the polarization curves showed that the protective mechanism corresponded to anodic-type inhibition. The addition of zinc undecylenate did not alter the inhibition mechanism but improved the biostability of the preservative oil, while maintaining a high level of protection of St3 steel against electrochemical corrosion.

Due to increasing consumer demands for the quality of ferrous metal products obtained by drawing, ongoing work is underway to optimize technological processes and select lubricants for the production of metal rods, wire, pipes, and other articles. One of the main factors affecting drawing quality is the quality of the final semifinished product drawn in the coarse-medium drawing section. Furthermore, the lubricant used for drawing is an important parameter determining the quality of the final semifinished product in the coarse-medium drawing section. The lubricant must effectively and continuously separate the rubbing surfaces and adhere firmly to them, withstand high pressures, ensure minimal wear of the die channel, have no harmful effects on maintenance personnel, and be inexpensive. It should not sinter, decompose, or delaminate. To increase drawing speed, various additives and supplements are added to fatty acid salts to enhance the lubricants’ antifriction, extreme-pressure, antiwear, and anticorrosion properties. In this study, by modifying layered materials with fluorinated surfactants, a dry drawing lubricant was produced that improves product quality and increases drawing speed by enhancing tribological properties and hydrophobicity. A layered material such as molybdenum disulfide modified with organofluorine surfactants proved to be the most effective.This work was prepared based on the results of research funded by the federal budget under a state assignment (research topic title: “Development of scientific and methodological foundations and methods for production and implementation of polymer, composite materials, and lubricant compositions for the benefit of the agro-industrial complex of the Russian Federation”; research topic code assigned by the founder: FSFM-2024-0018).

The work presents the results of a comprehensive study of the corrosion properties of cooling liquids for engines VN-RU-30 (ready-to-use) and VN-RU-C (concentrate). The tests were carried out in accordance with GOST (State Standart) 28084-89 in order to assess the corrosion effect on a multi-element metallic cooling system under static conditions. It is shown that cooling liquids VN-RU-30 and VN-RU-C provide high corrosion resistance of copper, brass, solder, steel, cast iron and aluminum alloys, while the corrosion rates are significantly lower than the standard values. Additionally, model tests simulating a cooling system previously subjected to corrosion destruction were performed. It was established that the use of VN-RU-30 stabilizes the state of damaged metallic surfaces and effectively suppresses the further development of corrosion. Full-scale tests lasting 46 months showed that the use of tap water leads to intensive corrosion and formation of deposits, whereas the use of VN-RU-30 ensures the preservation of metallic elements during long-term storage. The obtained results confirm the high efficiency of cooling liquids of the VN-RU series and substantiate the expediency of their use both in the operational mode and for long-term preservation of engine cooling systems.

The first title compound, C ₁₀ H ₇ FN ₂ OS, crystallizes in space group P 1 with two independent molecules in the asymmetric unit, which form a dimer with an R ² ₂ (8) motif through pairwise N—H...N hydrogen bonds. In the crystal of (I), N—H...O hydrogen bonds bind the dimers into zigzag ribbons running along the [100] direction, generating R ⁴ ₄ (14) motifs. The second title compound, C ₁₀ H ₇ ClN ₂ OS (space group I 2/ a ), contains one molecule in the asymmetric unit, which forms a dimer with an R ² ₂ (8) motif via inversion symmetry. In the extended structure, the molecules form zigzag ribbons in the [100] direction by N—H...N and N—H...O hydrogen bonds, resulting in consecutive R ⁴ ₁ (8) R ² ₁ (5) R ² ₂ (8) R ² ₁ (5) R ⁴ ₁ (8) motifs. The Hirshfeld surface analyses of the compounds (I) and (II) indicates that the most important factors influencing the crystal packing are H...H interactions [21.1% for molecule A of (I), 20.3% for molecule B of (I) and 21.0% for (II)].

Introduction. A promising class of corrosion inhibitors is volatile or vapor-phase ones. They evaporate at ambient temperatures adsorbing on metal surfaces and providing reliable corrosion protection. Volatile corrosion inhibitors penetrate crevices and gaps inaccessible to contact inhibitors, inhibiting corrosion processes along layers of corrosion products. Their use is justified by sealing the protected space, preventing inhibitor evaporation. Currently, there are no low-volatile corrosion inhibitors resistant to temperatures above 80°C, so various packaging materials with low moisture and gas permeability are used. The use of such materials for preserving metal products has revealed several disadvantages: the hygroscopic nature of paper, the degradation of volatile corrosion inhibitors at polymer extrusion temperatures, and the high degree of manual labor required during preservation. Aim of the Study. The study is aimed at developing an effective technology for protecting ferrous and non-ferrous metals using nitrogen-containing organic compounds – volatile corrosion inhibitors. Materials and Methods. Based on the results of electrochemical and accelerated tests, the corrosion rate, protection level, and inhibition coefficient were calculated. St3 steel plates were selected as the samples on which the anticorrosive effect of volatile corrosion inhibitors was tested. Laboratory tests were conducted to determine the protective effectiveness of the resulting inhibitors. The reagents included ethnalolamine, boric acid,mono(aminoethyl)borate, di(aminoethyl)borate, and tri(aminoethyl)borate. The reagent ratio and reaction temperature were varied during the study. Results. A series of volatile corrosion inhibitors were obtained in this study. It was determined that, in electrochemical testing in a 0.1 mol/l sodium chloride solution, the best results were obtained with a composition based on ethanolamine and boric acid ina three-to-one ratio, namely, tri(aminoethyl)borate. The optimal inhibitor concentration on steel surfaces during accelerated testing in an environment with 100% relative humidity is 200 g/m³. Discussion and Conclusion. The results obtained have potential for practical application in atmospheric corrosion protection of ferrous and non-ferrous metals. A promising area of application is the protection of steel equipment and electrical protection systems containing non-ferrous metals (copper, brass) using volatile inhibitors in agricultural production, mechanical engineering, and other fields.

In this study, we consider the synthesis of a surfactant from an oleochemical raw material. Physicochemical properties of the resulting substance are investigated to determine the optimal targeted application in industry. Using IR spectroscopy, the reaction mixture is tested during the synthesis for different reagent ratios to determine more exactly the structural formula of the obtained chemical compound.

Ethanolamine with boric acid can form various products, but there have not been any comprehensive studies on their properties as volatile corrosion inhibitors. The aim of thisstudy wasto synthesize products of interaction between ethanolamine and boric acid and to analyze anticorrosion properties of the obtained substances on ferrous and non-ferrous metals. To determine the composition and conditionsfor obtaining an inhibitor with high anticorrosion properties, the authors conducted experiments with a variable ratio of reagents and reaction temperature. As a result, they developed methodsfor obtaining volatile corrosion inhibitors. Four products were synthesized: ethanolamine and boric acid adduct, aminoethylborate, di(aminoethyl)borate and tri(aminoethyl) borate. The anticorrosion properties of the inhibitors were checked in accelerated tests. The evaluation of the protective ability was determined by gravimetric method, after which the corrosion rate, corrosion inhibition coefficient and degree of protection were calculated. Anticorrosive effect of volatile corrosion inhibitors wastested on specimen plates made of steel St3, copper M1 and alloys D16, L63. As a result of tests of the obtained inhibitors, di(aminoethyl)borate showed the best protective properties. Its maximum protective effect of 89.9% was observed on steel, the minimum one of 30.3% - on copper. The obtained results willsignificantly increase the degree of protection of ferrous and non-ferrous metal productsfrom corrosion during operation, transportation and storage while reducing the cost of their maintenance.

The analyzes of domestic and foreign steels used for the manufacture of agricultural machinery parts has been carried out. It is shown that the reliability

Created for the first time a novel corrosion inhibitor, which is amides of higher carboxylic acids (AHCA), is presented. To determine the composition and conditions of its production the experiments were conducted in which the ratio of the reagents was varied, as well as the reaction time at a temperature of 180-200 °C. It was proven that when donor and acceptor inhibitors are mixed at a mass ratio of 1:1 then synergistic effect is achieved. Such a mixture inhibiting both the cathodic and anodic processes allows us to classify this composition as a mixed corrosion inhibitor of the homosorption type.

The study’s main aim was to evaluate the effects of complex mineral fertilizers on the complex properties of heavy loam soils in the grey forests of Russia in terms of applying individual soil nutrition components from experiments with fodder beets. This study employed a rigorous and systematic approach to accomplish the defined goal. Specifically, the research was conducted within a seven-field crop rotation system, with fodder beets serving as the primary experimental crop. In addition, a model experiment resembling a vegetation trial was undertaken, incorporating seven distinct schemes involving various types of fertilizers. This design facilitated the evaluation of the effectiveness of each fertilizer type. The study results demonstrate that complex fertilizers impact the soil’s chemical and biophysical parameters. Soil acidity decreases through the use of complex, high-nitrogen fertilizers. Major chemical nutrients (nitrogen, phosphorus, and potassium) in plant biomass and soil also have a high degree of transition. It is explained by the effects of combining elements on the destruction intensity of the crystalline lattice in the basic structures of potassium, phosphorus, and nitrogen. There is also evidence that complex fertilizers can improve humus quality and replenish its reserves. All the aforementioned impacts of complex fertilizers on the crop contribute to the high productivity and yield of forage beet. The results of the study may help optimize the fertilization process, improve the quality and quantity of agricultural products, as well as increase soil fertility, and reduce the negative impact of agrochemicals on the environment.