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When using cathodic protection of steel in sea water, hydrogen can be accumulated on the cathode surface and penetrate deep into the metal. This rather dangerous phenomenon of hydrogen corrosion can lead to hydrogen embrittlement, i.e., to destruction of the metal. We present the results of studying the impact of the temperature and external tensile stresses on the hydrogenation of cathodically protected steel in calm and mobile Baltic sea water. Dependence of the inhibitory hydrogenation on the temperature and applied load under the action of benzenesulfapyridine chloride as an inhibitor was analyzed. An MIP-102 machine (wire samples) and special equipment (half-ring and plate lamellar samples) were used to provide smooth control of the applied load set by the deflection and controlled by dynamometers (lamellar samples were tested under constant deformation). When studying the effect of temperature on steel hydrogenation, the working cell was thermostatically controlled. The wire and plate samples were polarized for 96 h, and half-ring samples for 1 h. The potential was measured with respect to the silver chloride reference electrode. The layered distribution of absorbed hydrogen in the metal was determined using anodic dissolution. It is shown that external tensile stresses increase the hydrogen content in the surface layers of steel. Hydrogen absorbed by a metal changes the potential of the steel surface (the more absorbed hydrogen, the stronger change). It is also shown that hydrogen is absorbed by the metal more actively in moving seawater than in calm water, and an increase in the load contributes to an increase in hydrogen content in the metal both in calm and mobile seawater. However, the load did not affect the hydrogen absorption with the inhibitor present, thus providing reduction of the hydrogen content in the metal under loading.

The aim of this study was to assess the possibility of using wastes from pulp and paper industry as metal corrosion inhibitors. We studied protective properties of various systems, including the primers with rust modifiers developed on the basis of sulfite spent liquors and an upper coating layer of PF-115 enamel applied to a rusty surface. Using the gravimetric method and the method of polarization curves, we found that sulfite spent liquors inhibit steel corrosion in an acidic environment. We found that the P-2 rust modifier with an addition of lye + piperidine is the most effective inhibitor of steel rusting.

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An increase in the strength of steels is associated with a decrease in the content of impurities, which have a negative effect on the mechanical properties of steels. One of those impurities is hydrogen. It is known that at ultrahigh frequencies, due to the peculiarities of the distribution of alternating current over the cross section of a metal conductor, the conductivity is carried out by a thin surface layer (skin-effect). We present the results of using high-frequency currents for determination of the hydrogen content in a metal. The absorption of hydrogen by thin subsurface layers of steel is determined proceeding from a change in the voltage drop across the samples which depends on the resistance of the layers. The voltage drop as a function of the alternating current frequency is measured using a high-frequency generator, an HF-voltmeter, and an HF-galvanometer. Wire samples made of high-quality U8A carbon steel were used during testing procedure. At the same time, the amount of hydrogen absorbed by the steel was determined by the method of anodic dissolution. It is shown that the cathode-introduced hydrogen is unevenly distributed over the cross section of the sample. During the aging of cathodic hydrogenated steels of a U8A type, hydrogen diffusion from steels into the air takes place with an insignificant penetration of hydrogen into the deeper metal layers. Moreover, the hydrogen content and the resistance of the subsurface layers of the material increase with an increase in the current density during cathodic polarization. The results obtained can be used in nondestructive testing of the degree of hydrogenation of ferromagnetic products.