A very small magnetic field of corrosion current, of the order of 10⁻⁴ Oe, generated by isolated zinc inclusion in a copper platelet placed in electrolyte has been measured for the first time with a highly sensitive giant magneto-impedance magnetometer. The total corrosion current of the inclusion is estimated comparing the measured magnetic field distribution with corresponding theoretical calculation. The estimated value of the total corrosion current turns out to be in reasonable agreement with that one obtained in the standard gravimetric measurement.

The method of microarc oxidation of materials is described and its advantages over the anodization conventionally used to obtain protective coatings on the surface of light aluminum and constructional alloys are shown; the main notions of the mechanism of this process in the understanding of the authors of this article are presented.

Graphene oxide (GO) is an advanced additive improving the properties of various types of coatings and intensifying the deposition process. In this work, GO is used as an additive to the traditional phosphating solution of the widely used Russian low-carbon steel 08YU (DC04). The anticorrosion properties of the obtained phosphate coatings were investigated in neutral (0.5 M NaCl) and acidified (0.1 M Na₂SO₄ + 0.02 M H₂SO₄) aqueous solutions. Increasing the GO concentration in the phosphating solution to 0.3 g/L was found to improve the anticorrosion properties of the phosphate coatings in neutral NaCl solutions. At the same time, in acidified Na₂SO₄ solutions, the corrosion rate of 08YU steel with phosphate coatings increased as a function of the GO concentration. It is assumed that a possible reason for various corrosive behavior is the influence of the GO plates distributed in the coating on the rate of the oxygen or hydrogen reduction reactions.

The article investigates the structure of sheets made from the Al – Ca – Mn aluminum alloy system, coated using the micro-arc oxidation (MAO) method. The alloy sheets with a composition of Al – 2.5%Ca – 1.5%Mn – 0.4%Fe –0.2%Si – 0.2%Cu – 0.8%Zn were produced through hot rolling and subsequently treated in a low-alkaline alkalinesilicate electrolyte. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) methods were employed to assess the microstructure and phase composition during the study. The results revealed a high dispersion of the alloy structure with various phases present, such as Al4Ca and Al6(Mn, Fe). The sizes of the dispersed eutectic precipitates ranged from 1.5 to 5 micrometers. The thickness of the obtained MAO coatings was between 20 and 30 micrometers. The coating structure in the middle of the samples was uniform, without through porosity, although some isolated pores and cracks were observed. X-ray phase analysis indicated the presence of aluminum oxides in the coating, such as α-Al2O3 and η-Al2O3. Additionally, other alloying elements like calcium, potassium, and sodium were noted. An important aspect was that the structure of the alloy near the coating remained stable, indicating good adhesion between the aluminum matrix and the coating. The authors emphasize the need for further research to optimize processes for producing strong and wear-resistant coatings, especially for applications in Arctic conditions. This work lays the groundwork for developing new structural materials with multifunctional coatings that could be beneficial in various industries, including automotive and shipbuilding. The work was carried out within the framework of the RNF project 23-79-00055 “Creation of scientific bases for the development of new structural materials of reduced density with protective multifunctional ceramic-like coatings for use in transport systems of the Arctic region” (coating, SEM, XRD) and at the expense of the grant named after P. L. Kapitsa of Moscow Polytechnic University, implemented within the framework of the program “Priority 2030” (melting, casting, deformation processing). The structure study was performed using the scientific equipment of the Research Chemical and Analytical Center of SIC Kurchatov Institute.

Based on the experimental data, the mechanism of the influence of the cathodic component of the ac current on the growth kinetics and the limiting thickness of the microarc coatings formed on the surface of aluminum and magnesium alloys is suggested. It is shown that, during microarc oxidation (MAO), the cathode component of the ac current either increases (in the case of the Al alloy) or decreases (in the case of the Mg alloy) the number of effective microcharge discharges due to an increase in the electrolyte pH in the through pores of the coating and the elevation of the temperature of the MAO process.